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 PRELIMINARY
C8051F018 C8051F019
Mixed-Signal 16KB ISP FLASH MCU Family
ANALOG PERIPHERALS
SAR ADC
10-bit 1LSB INL; No Missing Codes Programmable Throughput up to 100ksps Up to 8 External Inputs; Programmable as SingleEnded or Differential Data Dependent Windowed Interrupt Generator Built-in Temperature Sensor ( 3 C) Programmable Hysteresis Values Configurable to Generate Interrupts or Reset 2.4V; 15 ppm/ C Available on External Pin
HIGH SPEED 8051 C CORE
-
Pipelined Instruction Architecture; Executes 70% of Instruction Set in 1 or 2 System Clocks Up to 25MIPS Throughput with 25MHz Clock Expanded Interrupt Handler 1280 (256 + 1k) Bytes Internal Data RAM 16k Bytes FLASH; In-System Programmable in 512 byte Sectors 4 Byte-Wide Port I/O; All are 5V tolerant Hardware SMBusTM (I2CTM Compatible), SPITM, and UART Serial Ports Available Concurrently Programmable 16-bit Counter/Timer Array with Five Capture/Compare Modules Four General Purpose 16-bit Counter/Timers Dedicated Watch-Dog Timer Bi-directional Reset Internal Programmable Oscillator: 2-to-16MHz External Oscillator: Crystal, RC,C, or Clock Can Switch Between Clock Sources on-the-fly; Useful in Power Saving Modes Typical Operating Current: 12.5mA @ 25MHz Multiple Power Saving Sleep and Shutdown Modes
MEMORY
-
Two Analog Comparators

DIGITAL PERIPHERALS
-
Voltage Reference Precision VDD Monitor/Brown-out Detector
On-Chip Debug Circuitry Facilitates Full Speed, NonIntrusive In-System Debug (No Emulator Required!) Provides Breakpoints, Single Stepping, Watchpoints, Stack Monitor Inspect/Modify Memory and Registers Superior Performance to Emulation Systems Using ICEChips, Target Pods, and Sockets IEEE1149.1 Compliant Boundary Scan Low Cost Development Kit
ON-CHIP JTAG DEBUG & BOUNDRY SCAN
CLOCK SOURCES
SUPPLY VOLTAGE ........................ 2.8V to 3.6V
-
64-Pin TQFP, 48-Pin TQFP Temperature Range: -40 C to +85 C
ANALOG PERIPHERALS
TEMP SENSOR
DIGITAL I/O
SMBus SPI Bus UART Timer 0 CROSSBAR
AMUX
ADC
VREF
+ + -
Timer 1 Timer 2 Timer 3
VOLTAGE COMPARATORS
HIGH-SPEED CONTROLLER CORE
8051 CPU (25MIPS) 16KB ISP FLASH CLOCK DEBUG JTAG CIRCUIT CIRCUITRY 1280 B 21 SANITY SRAM INTERRUPTS CONTROL
Page 1
CYGNAL Integrated Products, Inc. 2002
Port 3
Port 2
Port 1
10-Bit SAR
Port 0
PCA
1.2002; Rev. 1.0
PRELIMINARY
TABLE OF CONTENTS
1.
C8051F018 C8051F019
SYSTEM OVERVIEW ....................................................................................................... 7
Table 1.1. Product Selection Guide....................................................................................................................7 Figure 1.1. C8051F018 Block Diagram .............................................................................................................8 Figure 1.2. C8051F019 Block Diagram .............................................................................................................9 1.1. CIP-51TM CPU ...........................................................................................................................................10 Figure 1.3. Comparison of Peak MCU Execution Speeds................................................................................10 Figure 1.4. On-Board Clock and Reset ............................................................................................................11 1.2. On-Board Memory .....................................................................................................................................12 Figure 1.5. On-Board Memory Map ................................................................................................................12 1.3. JTAG Debug and Boundary Scan ..............................................................................................................13 Figure 1.6. Debug Environment Diagram ........................................................................................................13 1.4. Programmable Digital I/O and Crossbar ....................................................................................................14 Figure 1.7. Digital Crossbar Diagram ..............................................................................................................14 1.5. Programmable Counter Array ....................................................................................................................15 Figure 1.8. PCA Block Diagram ......................................................................................................................15 1.6. Serial Ports .................................................................................................................................................15 1.7. Analog to Digital Converter .......................................................................................................................16 Figure 1.9. ADC Diagram ................................................................................................................................16 1.8. Comparators ...............................................................................................................................................17 Figure 1.10. Comparator Diagram ...................................................................................................................17
2. 3. 4.
ABSOLUTE MAXIMUM RATINGS*............................................................................ 18 GLOBAL DC ELECTRICAL CHARACTERISTICS .................................................. 18 PINOUT AND PACKAGE DEFINITIONS.................................................................... 19
Table 4.1. Pin Definitions ................................................................................................................................19 Figure 4.1. TQFP-64 Pinout Diagram..............................................................................................................21 Figure 4.2. TQFP-64 Package Drawing ...........................................................................................................22 Figure 4.3. TQFP-48 Pinout Diagram..............................................................................................................23 Figure 4.4. TQFP-48 Package Drawing ...........................................................................................................24
5.
ADC..................................................................................................................................... 25
Figure 5.1. 10-Bit ADC Functional Block Diagram.........................................................................................25 5.1. Analog Multiplexer ....................................................................................................................................25 5.2. ADC Modes of Operation ..........................................................................................................................26 Figure 5.2. 10-Bit ADC Track and Conversion Example Timing....................................................................26 Figure 5.3. Temperature Sensor Transfer Function..........................................................................................27 Figure 5.4. AMX0CF: AMUX Configuration Register....................................................................................27 Figure 5.5. AMX0SL: AMUX Channel Select Register (C8051F01x)............................................................28 Figure 5.6. ADC0CF: ADC Configuration Register (C8051F01x) ..................................................................29 Figure 5.7. ADC0CN: ADC Control Register..................................................................................................30 Figure 5.8. ADC0H: ADC Data Word MSB Register ....................................................................................31 Figure 5.9. ADC0L: ADC Data Word LSB Register ......................................................................................31 5.3. ADC Programmable Window Detector......................................................................................................32 Figure 5.10. ADC0GTH: ADC Greater-Than Data High Byte Register ..........................................................32 Figure 5.11. ADC0GTL: ADC Greater-Than Data Low Byte Register ...........................................................32 Figure 5.12. ADC0LTH: ADC Less-Than Data High Byte Register ...............................................................32 Figure 5.13. ADC0LTL: ADC Less-Than Data Low Byte Register ................................................................32 Figure 5.14. 10-Bit ADC Window Interrupt Examples, Right Justified Data ..................................................33 Figure 5.15. 10-Bit ADC Window Interrupt Examples, Left Justified Data ....................................................34 Table 5.1. 10-Bit ADC Electrical Characteristics ............................................................................................35
6.
COMPARATORS.............................................................................................................. 36
Figure 6.1. Comparator Functional Block Diagram .........................................................................................36 Figure 6.2. Comparator Hysteresis Plot ...........................................................................................................37
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
PRELIMINARY
Figure 6.3. CPT0CN: Comparator 0 Control Register .....................................................................................38 Figure 6.4. CPT1CN: Comparator 1 Control Register .....................................................................................39 Table 6.1. Comparator Electrical Characteristics.............................................................................................40
7.
VOLTAGE REFERENCE................................................................................................ 41
Figure 7.1. Voltage Reference Functional Block Diagram ..............................................................................41 Figure 7.2. REF0CN: Reference Control Register ...........................................................................................42 Table 7.1. Reference Electrical Characteristics................................................................................................42
8.
CIP-51 CPU ........................................................................................................................ 43
Figure 8.1. CIP-51 Block Diagram ..................................................................................................................43 8.1. INSTRUCTION SET .................................................................................................................................44 Table 8.1. CIP-51 Instruction Set Summary.....................................................................................................45 8.2. MEMORY ORGANIZATION...................................................................................................................48 Figure 8.2. Memory Map .................................................................................................................................49 8.3. SPECIAL FUNCTION REGISTERS ........................................................................................................50 Table 8.2. Special Function Register Memory Map.........................................................................................50 Table 8.3. Special Function Registers ..............................................................................................................50 Figure 8.3. SP: Stack Pointer ...........................................................................................................................54 Figure 8.4. DPL: Data Pointer Low Byte .........................................................................................................54 Figure 8.5. DPH: Data Pointer High Byte........................................................................................................54 Figure 8.6. PSW: Program Status Word ..........................................................................................................55 Figure 8.7. ACC: Accumulator ........................................................................................................................56 Figure 8.8. B: B Register..................................................................................................................................56 8.4. INTERRUPT HANDLER..........................................................................................................................57 Table 8.4. Interrupt Summary ..........................................................................................................................58 Figure 8.9. IE: Interrupt Enable .......................................................................................................................59 Figure 8.10. IP: Interrupt Priority ....................................................................................................................60 Figure 8.11. EIE1: Extended Interrupt Enable 1 ..............................................................................................61 Figure 8.12. EIE2: Extended Interrupt Enable 2 ..............................................................................................62 Figure 8.13. EIP1: Extended Interrupt Priority 1 .............................................................................................63 Figure 8.14. EIP2: Extended Interrupt Priority 2 .............................................................................................64 8.5. Power Management Modes ........................................................................................................................65 Figure 8.15. PCON: Power Control Register ...................................................................................................66
9.
FLASH MEMORY............................................................................................................ 67
9.1. Programming The Flash Memory...............................................................................................................67 Table 9.1. FLASH Memory Electrical Characteristics.....................................................................................67 9.2. Non-volatile Data Storage ..........................................................................................................................68 9.3. Security Options.........................................................................................................................................68 Figure 9.1. PSCTL: Program Store RW Control..............................................................................................68 Figure 9.2. Flash Program Memory Security Bytes ..........................................................................................69 Figure 9.3. FLACL: Flash Access Limit ..........................................................................................................70 Figure 9.4. FLSCL: Flash Memory Timing Prescaler ......................................................................................71
10. EXTERNAL RAM............................................................................................................. 72
Figure 10.1. EMI0CN: External Memory Interface Control ............................................................................72
11. RESET SOURCES ............................................................................................................ 73
Figure 11.1. Reset Sources Diagram ................................................................................................................73 11.1. Power-on Reset ......................................................................................................................................74 11.2. Software Forced Reset ...........................................................................................................................74 Figure 11.2. VDD Monitor Timing Diagram ...................................................................................................74 11.3. Power-fail Reset .....................................................................................................................................74 11.4. External Reset ........................................................................................................................................75 11.5. Missing Clock Detector Reset ................................................................................................................75 11.6. Comparator 0 Reset................................................................................................................................75 11.7. External CNVSTR Pin Reset .................................................................................................................75 11.8. Watchdog Timer Reset...........................................................................................................................75 CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
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PRELIMINARY
C8051F018 C8051F019
Figure 11.3. WDTCN: Watchdog Timer Control Register ..............................................................................76 Figure 11.4. RSTSRC: Reset Source Register .................................................................................................77 Table 11.1. Reset Electrical Characteristics.....................................................................................................78
12. OSCILLATOR................................................................................................................... 79
Figure 12.1. Oscillator Diagram.......................................................................................................................79 Figure 12.2. OSCICN: Internal Oscillator Control Register ............................................................................80 Table 12.1. Internal Oscillator Electrical Characteristics.................................................................................80 Figure 12.3. OSCXCN: External Oscillator Control Register..........................................................................81 12.1. External Crystal Example.......................................................................................................................82 12.2. External RC Example.............................................................................................................................82 12.3. External Capacitor Example...................................................................................................................82
13. PORT INPUT/OUTPUT ................................................................................................... 83
13.1. Priority Cross Bar Decoder ....................................................................................................................83 13.2. Port I/O Initialization .............................................................................................................................83 Figure 13.1. Port I/O Functional Block Diagram .............................................................................................84 Figure 13.2. Port I/O Cell Block Diagram .......................................................................................................84 Table 13.1. Crossbar Priority Decode ..............................................................................................................85 Figure 13.3. XBR0: Port I/O CrossBar Register 0 ...........................................................................................86 Figure 13.4. XBR1: Port I/O CrossBar Register 1 ...........................................................................................87 Figure 13.5. XBR2: Port I/O CrossBar Register 2 ...........................................................................................88 13.3. General Purpose Port I/O .......................................................................................................................89 13.4. Configuring Ports Which are not Pinned Out.........................................................................................89 Figure 13.6. P0: Port0 Register ........................................................................................................................89 Figure 13.7. PRT0CF: Port0 Configuration Register .......................................................................................89 Figure 13.8. P1: Port1 Register ........................................................................................................................90 Figure 13.9. PRT1CF: Port1 Configuration Register .......................................................................................90 Figure 13.10. PRT1IF: Port1 Interrupt Flag Register ......................................................................................90 Figure 13.11. P2: Port2 Register ......................................................................................................................91 Figure 13.12. PRT2CF: Port2 Configuration Register .....................................................................................91 Figure 13.13. P3: Port3 Register ......................................................................................................................92 Figure 13.14. PRT3CF: Port3 Configuration Register .....................................................................................92 Table 13.2. Port I/O DC Electrical Characteristics ..........................................................................................92
14. SMBus / I2C Bus................................................................................................................ 93
Figure 14.1. SMBus Block Diagram ................................................................................................................93 Figure 14.2. Typical SMBus Configuration .....................................................................................................94 14.1. Supporting Documents ...........................................................................................................................94 14.2. Operation................................................................................................................................................95 Figure 14.3. SMBus Transaction......................................................................................................................95 14.3. Arbitration..............................................................................................................................................96 14.4. Clock Low Extension .............................................................................................................................96 14.5. Timeouts.................................................................................................................................................96 14.6. SMBus Special Function Registers ........................................................................................................96 Figure 14.4. SMB0CN: SMBus Control Register .............................................................................................98 Figure 14.5. SMB0CR: SMBus Clock Rate Register.......................................................................................99 Figure 14.6. SMB0DAT: SMBus Data Register ............................................................................................100 Figure 14.7. SMB0ADR: SMBus Address Register ......................................................................................100 Figure 14.8. SMB0STA: SMBus Status Register...........................................................................................101 Table 14.1. SMBus Status Codes...................................................................................................................102
15. SERIAL PERIPHERAL INTERFACE BUS ................................................................ 103
Figure 15.1. SPI Block Diagram ....................................................................................................................103 Figure 15.2. Typical SPI Interconnection ......................................................................................................104 15.1. Signal Descriptions ..............................................................................................................................104 15.2. Operation..............................................................................................................................................105 Figure 15.3. Full Duplex Operation ...............................................................................................................105
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
PRELIMINARY
15.3. Serial Clock Timing .............................................................................................................................106 Figure 15.4. Data/Clock Timing Diagram......................................................................................................106 15.4. SPI Special Function Registers ............................................................................................................107 Figure 15.5. SPI0CFG: SPI Configuration Register.......................................................................................107 Figure 15.6. SPI0CN: SPI Control Register...................................................................................................108 Figure 15.7. SPI0CKR: SPI Clock Rate Register...........................................................................................109 Figure 15.8. SPI0DAT: SPI Data Register.....................................................................................................109
16. UART ................................................................................................................................ 110
Figure 16.1. UART Block Diagram ...............................................................................................................110 16.1. UART Operational Modes ...................................................................................................................111 Table 16.1. UART Modes..............................................................................................................................111 Figure 16.2. UART Mode 0 Interconnect ......................................................................................................111 Figure 16.3. UART Mode 0 Timing Diagram................................................................................................111 Figure 16.4. UART Mode 1 Timing Diagram................................................................................................112 Figure 16.5. UART Modes 1, 2, and 3 Interconnect Diagram .......................................................................113 Figure 16.6. UART Modes 2 and 3 Timing Diagram ....................................................................................113 16.2. Multiprocessor Communications..........................................................................................................114 Figure 16.7. UART Multi-Processor Mode Interconnect Diagram ................................................................114 Table 16.2. Oscillator Frequencies for Standard Baud Rates.........................................................................115 Figure 16.8. SBUF: Serial (UART) Data Buffer Register..............................................................................115 Figure 16.9. SCON: Serial Port Control Register ..........................................................................................116
17. TIMERS............................................................................................................................ 117
17.1. Timer 0 and Timer 1 ............................................................................................................................117 Figure 17.1. T0 Mode 0 Block Diagram ........................................................................................................118 Figure 17.2. T0 Mode 2 Block Diagram ........................................................................................................119 Figure 17.3. T0 Mode 3 Block Diagram ........................................................................................................120 Figure 17.4. TCON: Timer Control Register .................................................................................................121 Figure 17.5. TMOD: Timer Mode Register ...................................................................................................122 Figure 17.6. CKCON: Clock Control Register...............................................................................................123 Figure 17.7. TL0: Timer 0 Low Byte.............................................................................................................124 Figure 17.8. TL1: Timer 1 Low Byte.............................................................................................................124 Figure 17.9. TH0: Timer 0 High Byte............................................................................................................124 Figure 17.10. TH1: Timer 1 High Byte..........................................................................................................124 17.2. Timer 2.................................................................................................................................................125 Figure 17.11. T2 Mode 0 Block Diagram ......................................................................................................126 Figure 17.12. T2 Mode 1 Block Diagram ......................................................................................................127 Figure 17.13. T2 Mode 2 Block Diagram ......................................................................................................128 Figure 17.14. T2CON: Timer 2 Control Register ..........................................................................................129 Figure 17.15. RCAP2L: Timer 2 Capture Register Low Byte .......................................................................130 Figure 17.16. RCAP2H: Timer 2 Capture Register High Byte ......................................................................130 Figure 17.17. TL2: Timer 2 Low Byte...........................................................................................................130 Figure 17.18. TH2: Timer 2 High Byte..........................................................................................................130 17.3. Timer 3.................................................................................................................................................131 Figure 17.19. Timer 3 Block Diagram ...........................................................................................................131 Figure 17.20. TMR3CN: Timer 3 Control Register .......................................................................................131 Figure 17.21. TMR3RLL: Timer 3 Reload Register Low Byte .....................................................................132 Figure 17.22. TMR3RLH: Timer 3 Reload Register High Byte ....................................................................132 Figure 17.23. TMR3L: Timer 3 Low Byte.....................................................................................................132 Figure 17.24. TMR3H: Timer 3 High Byte....................................................................................................132
18. PROGRAMMABLE COUNTER ARRAY ................................................................... 133
Figure 18.1. PCA Block Diagram ..................................................................................................................133 18.1. Capture/Compare Modules...................................................................................................................134 Table 18.1. PCA0CPM Register Settings for PCA Capture/Compare Modules ............................................134 Figure 18.2. PCA Interrupt Block Diagram ...................................................................................................134
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
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PRELIMINARY
C8051F018 C8051F019
Figure 18.3. PCA Capture Mode Diagram.....................................................................................................135 Figure 18.4. PCA Software Timer Mode Diagram.........................................................................................136 Figure 18.5. PCA High Speed Output Mode Diagram...................................................................................136 Figure 18.6. PCA PWM Mode Diagram........................................................................................................137 18.2. PCA Counter/Timer .............................................................................................................................138 Table 18.2. PCA Timebase Input Options .....................................................................................................138 Figure 18.7. PCA Counter/Timer Block Diagram..........................................................................................138 18.3. Register Descriptions for PCA .............................................................................................................139 Figure 18.8. PCA0CN: PCA Control Register ................................................................................................139 Figure 18.9. PCA0MD: PCA Mode Register.................................................................................................140 Figure 18.10. PCA0CPMn: PCA Capture/Compare Registers.......................................................................141 Figure 18.11. PCA0L: PCA Counter/Timer Low Byte ..................................................................................142 Figure 18.12. PCA0H: PCA Counter/Timer High Byte .................................................................................142 Figure 18.13. PCA0CPLn: PCA Capture Module Low Byte .........................................................................142 Figure 18.14. PCA0CPHn: PCA Capture Module High Byte........................................................................142
19. JTAG (IEEE 1149.1) ....................................................................................................... 143
Figure 19.1. IR: JTAG Instruction Register ...................................................................................................143 19.1. Boundary Scan .....................................................................................................................................144 Table 19.1. Boundary Data Register Bit Definitions......................................................................................144 Figure 19.2. DEVICEID: JTAG Device ID Register .....................................................................................145 19.2. Flash Programming Commands ...........................................................................................................146 Figure 19.3. FLASHCON: JTAG Flash Control Register..............................................................................147 Figure 19.4. FLASHADR: JTAG Flash Address Register .............................................................................147 Figure 19.5. FLASHDAT: JTAG Flash Data Register...................................................................................148 Figure 19.6. FLASHSCL: JTAG Flash Scale Register ..................................................................................148 19.3. Debug Support .....................................................................................................................................149
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
1. SYSTEM OVERVIEW
PRELIMINARY
The C8051F018/9 are fully integrated mixed-signal System on a Chip MCUs with a true 10-bit multi-channel ADC. See the Product Selection Guide in Table 1.1 for a quick reference of each MCUs' feature set. Each has two voltage comparators, a voltage reference, and an 8051-compatible microcontroller core with 16kbytes of FLASH memory and 1.25kbytes of RAM. There are also I2C/SMBus, UART, and SPI serial interfaces implemented in hardware (not "bit-banged" in user software) as well as a Programmable Counter/Timer Array (PCA) with five capture/compare modules. There are also 4 general-purpose 16-bit timers and 4 byte-wide general-purpose digital Port I/O. With an on-board VDD monitor, WDT, and clock oscillator, the MCUs are truly stand-alone System-on-a-Chip solutions. Each MCU effectively configures and manages the analog and digital peripherals. The FLASH memory can be reprogrammed even in-circuit, providing non-volatile data storage, and also allowing field upgrades of the 8051 firmware. Each MCU can also individually shut down any or all of the peripherals to conserve power. On-board JTAG debug support allows non-intrusive (uses no on-chip resources), full speed, in-circuit debug using the production MCU installed in the final application. This debug system supports inspection and modification of memory and registers, setting breakpoints, watchpoints, single stepping, and run and halt commands. All analog and digital peripherals are fully functional when using JTAG debug. Each MCU is specified for 2.8V-to-3.6V operation over the industrial temperature range (-45C to +85C). The Port I/Os, /RST, and JTAG pins are tolerant for input signals up to 5V. The C8051F018 is available in the 64-pin TQFP (see block diagram in Figure 1.1). The C8051F019 is available in the 48-pin TQFP (see block diagram in Figure 1.2).
Table 1.1. Product Selection Guide
Programmable Counter Array
ADC Max Speed (ksps)
ADC Resolution (bits)
Voltage Comparators
Temperature Sensor
Voltage Reference
Digital Port I/O's
FLASH Memory
Timers (16-bit)
MIPS (Peak)
ADC Inputs
SMBus/I2C
C8051F018 C8051F019
25 25
16k 16k
1280 1280



4 4

32 16
10 10
100 100
8 8


2 2
64TQFP 48TQFP
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
Package
UART
RAM
SPI
Page 7
PRELIMINARY
Figure 1.1. C8051F018 Block Diagram
VDD VDD VDD DGND DGND DGND AV+ AV+ AGND AGND
C8051F018 C8051F019
Digital Power
UART SMBus
Analog Power
SPI Bus PCA 16kbyte FLASH 256 byte RAM 1024 byte XRAM Timers 0,1,2 Timer 3 Port 0 Latch Port 1 Latch Port 2 Latch
TCK TMS TDI TDO
JTAG Logic
Boundary Scan Debug HW
Reset
/RST
VDD Monitor External Oscillator Circuit Internal Oscillator
VREF
8 0 5 1 C o r e
C R O S S B A R S W I T C H
P 0 D r v P 1 D r v P 2 D r v P 3
P0.0 P0.1 P0.2 P0.3 P0.4 P0.5 P0.6 P0.7 P1.0 P1.1 P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 P2.0 P2.1 P2.2 P2.3 P2.4 P2.5 P2.6 P2.7 P3.0 P3.1 P3.2 P3.3 P3.4 P3.5 P3.6 P3.7 NC NC
WDT
XTAL1 XTAL2
System Clock
SFR Bus
Port 3 Latch
D r v
VREF
AIN0 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7
A M U X
Prog Gain
ADC 100ksps
TEMP
CP0+ CP0CP1+ CP1-
CP0
CP1
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
PRELIMINARY
Figure 1.2. C8051F019 Block Diagram
VDD VDD DGND DGND DGND DGND AV+ AV+ AGND AGND
Digital Power
UART SMBus
Analog Power
SPI Bus PCA 16kbyte FLASH 256 byte RAM 1024 byte XRAM Timers 0,1,2 Timer 3 Port 0 Latch Port 1 Latch Port 2 Latch
TCK TMS TDI TDO
JTAG Logic
Boundary Scan Debug HW
Reset
/RST
VDD Monitor External Oscillator Circuit Internal Oscillator
VREF
8 0 5 1 C o r e
C R O S S B A R S W I T C H
P 0 D r v P 1 D r v P 2 D r v P 3
P0.0 P0.1 P0.2 P0.3 P0.4 P0.5 P0.6 P0.7 P1.0 P1.1 P1.2 P1.3 P1.4 P1.5 P1.6 P1.7
WDT
XTAL1 XTAL2
System Clock
SFR Bus
Port 3 Latch
D r v
VREF
NC
AIN0 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7
NC
A M U X
Prog Gain
ADC 100ksps
TEMP
CP0+ CP0CP1+ CP1-
CP0
CP1
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
Page 9
PRELIMINARY
1.1.
1.1.1.
C8051F018 C8051F019
CIP-51TM CPU
Fully 8051 Compatible
The C8051F018/9 utilizes Cygnal's proprietary CIP-51 microcontroller core. The CIP-51 is fully compatible with the MCS-51TM instruction set. Standard 803x/805x assemblers and compilers can be used to develop software. The core has all the peripherals included with a standard 8052, including four 16-bit counter/timers, a full-duplex UART, 256 bytes of internal RAM space, 128 byte Special Function Register (SFR) address space, and four byte-wide I/O Ports.
1.1.2.
Improved Throughput
The CIP-51 employs a pipelined architecture that greatly increases its instruction throughput over the standard 8051 architecture. In a standard 8051, all instructions except for MUL and DIV take 12 or 24 system clock cycles to execute with a maximum system clock of 12-to-24MHz. By contrast, the CIP-51 core executes 70% of its instructions in one or two system clock cycles, with only four instructions taking more than four system clock cycles. The CIP-51 has a total of 109 instructions. The number of instructions versus the system clock cycles to execute them is as follows: Instructions Clocks to Execute 26 1 50 2 5 2/3 14 3 7 3/4 3 4 1 4/5 2 5 1 8
With the CIP-51's maximum system clock at 25MHz, it has a peak throughput of 25MIPS. Figure 1.3 shows a comparison of peak throughputs of various 8-bit microcontroller cores with their maximum system clocks.
Figure 1.3. Comparison of Peak MCU Execution Speeds
25
20
MIPS
15
10
5
Cygnal Microchip Philips ADuC812 CIP-51 PIC17C75x 80C51 8051 (25MHz clk) (33MHz clk) (33MHz clk) (16MHz clk)
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
1.1.3. Additional Features
PRELIMINARY
The C8051F018/9 has several key enhancements both inside and outside the CIP-51 core to improve its overall performance and ease of use in the end applications. The extended interrupt handler provides 21 interrupt sources into the CIP-51 (as opposed to 7 for the standard 8051), allowing the numerous analog and digital peripherals to interrupt the controller. An interrupt driven system requires less intervention by the MCU, giving it more effective throughput. The extra interrupt sources are very useful when building multi-tasking, real-time systems. There are up to seven reset sources for the MCU: an on-board VDD monitor, a Watchdog Timer, a missing clock detector, a voltage level detection from Comparator 0, a forced software reset, the CNVSTR pin, and the /RST pin. The /RST pin is bi-directional, accommodating an external reset, or allowing the internally generated POR to be output on the /RST pin. Each reset source except for the VDD monitor and Reset Input Pin may be disabled by the user in software. The WDT may be permanently enabled in software after a power-on reset during MCU initialization. The MCU has an internal, stand alone clock generator which is used by default as the system clock after any reset. If desired, the clock source may be switched on the fly to the external oscillator, which can use a crystal, ceramic resonator, capacitor, RC, or external clock source to generate the system clock. This can be extremely useful in low power applications, allowing the MCU to run from a slow (power saving) external crystal source, while periodically switching to the fast (up to 16MHz) internal oscillator as needed.
Figure 1.4. On-Board Clock and Reset
VDD
(Port I/O)
Crossbar
CNVSTR
(CNVSTR reset enable)
Supply Monitor
+ -
Comparator 0 CP0+ CP0+ (CP0 reset enable)
Supply Reset Timeout
(wired-OR)
/RST
Missing Clock Detector (oneshot)
EN
WDT
Reset Funnel
EN
PRE
MCD Enable
WDT Enable
Internal Clock Generator
System Clock Clock Select
XTAL1 XTAL2
OSC
CIP-51 Microcontroller Core
Extended Interrupt Handler
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
WDT Strobe Software Reset System Reset
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PRELIMINARY
1.2. On-Board Memory
C8051F018 C8051F019
The CIP-51 has a standard 8051 program and data address configuration. It includes 256 bytes of data RAM, with the upper 128 bytes dual-mapped. Indirect addressing accesses the upper 128 bytes of general purpose RAM, and direct addressing accesses the 128 byte SFR address space. The lower 128 bytes of RAM are accessible via direct and indirect addressing. The first 32 bytes are addressable as four banks of general-purpose registers, and the next 16 bytes can be byte addressable or bit addressable. The CIP-51 additionally has a 1024 byte RAM block in the external data memory address space. This 1024 byte block can be addressed over the entire 64k external data memory address range (see Figure 1.5). The MCU's program memory consists of 16k + 128 bytes of FLASH. This memory may be reprogrammed insystem in 512 byte sectors, and requires no special off-chip programming voltage. The 512 bytes from addresses 0x3E00 to 0x3FFF are reserved for factory use. The additional 128 byte block is located at address 0x8000. See Figure 1.5 for the MCU system memory map.
Figure 1.5. On-Board Memory Map
PROGRAM MEMORY
0x807F 0x8000 0x7FFF 0x3E00 0x3DFF FLASH (In-System Programmable in 512 Byte Sectors) 0x0000 0x30 0x2F 0x20 0x1F 0x00 FLASH (In-System Programmable) RESERVED 0xFF 0x80 0x7F
DATA MEMORY INTERNAL DATA ADDRESS SPACE
Upper 128 RAM (Indirect Addressing Only) (Direct and Indirect Addressing) Bit Addressable General Purpose Registers Special Function Register's (Direct Addressing Only)
Lower 128 RAM (Direct and Indirect Addressing)
EXTERNAL DATA ADDRESS SPACE
0xFFFF 0xFC00
(same 1024 byte RAM block )
0x0BFF 0x0800
(same 1024 byte RAM block )
0x07FF (same 1024 byte RAM block ) 0x0400 0x03FF 0x0000
The same 1024 byte RAM block can be addressed on 1k boundaries throughout the 64k External Data Memory space.
RAM - 1024 Bytes
(accessable using MOVX instruction)
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
1.3.
PRELIMINARY
JTAG Debug and Boundary Scan
The C8051F018/9 has on-chip JTAG and debug circuitry that provide non-intrusive, full speed, in-circuit debug using the production part installed in the end application using the four-pin JTAG I/F. The JTAG port is fully compliant to IEEE 1149.1, providing full boundary scan for test and manufacturing purposes. Cygnal's debug system supports inspection and modification of memory and registers, breakpoints, watchpoints, a stack monitor, and single stepping. No additional target RAM, program memory, timers, or communications channels are required. All the digital and analog peripherals are functional and work correctly while debugging. All the peripherals (except for the ADC) are stalled when the MCU is halted, during single stepping, or at a breakpoint in order to keep them in sync. The C8051F015DK is a development kit with all the hardware and software necessary to develop application code and perform in-circuit debug with the C8051F018/9 MCUs. The kit includes software with a developer's studio and debugger, an integrated 8051 assembler, and an RS-232 to JTAG protocol translator module referred to as the EC. It also has a target application board with a C8051F015 MCU installed and a large prototyping area, plus the RS-232 and JTAG cables, and wall-mount power supply. The Development Kit requires a Windows 95/98/NT/2000/XP computer with one available RS-232 serial port. As shown in Figure 1.6, the PC is connected via RS-232 to the EC. A six-inch ribbon cable connects the EC to the user's application board, picking up the four JTAG pins and VDD and GND. The EC takes its power from the application board. It requires roughly 20mA at 2.8-3.6V. For applications where there is not sufficient power available from the target board, the provided power supply can be connected directly to the EC. This is a vastly superior configuration for developing and debugging embedded applications compared to standard MCU Emulators, which use on-board "ICE Chips" and target cables and require the MCU in the application board to be socketed. Cygnal's debug environment both increases ease of use and preserves the performance of the precision analog peripherals.
Figure 1.6. Debug Environment Diagram
CYGNAL Integrated Development Environment WINDOWS 95/98/NT/2000/XP
RS-232
EC
JTAG (x4), VDD, GND
VDD
GND
TARGET PCB
C8051 F015
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CYGNAL Integrated Products, Inc. 2002
Page 13
PRELIMINARY
1.4. Programmable Digital I/O and Crossbar
C8051F018 C8051F019
The standard 8051 Ports (0, 1, 2, and 3) are available on the MCUs. All four ports are pinned out on the F018. Ports 0 and 1 are pinned out on the F019. The Ports not pinned out are still available for software use as general purpose registers. The Port I/O behave like the standard 8051 with a few enhancements. Each Port I/O pin can be configured as either a push-pull or open-drain output. Also, the "weak pull-ups" which are normally fixed on an 8051 can be globally disabled, providing additional power saving capabilities for low power applications. Perhaps the most unique enhancement is the Digital Crossbar. This is essentially a large digital switching network that allows mapping of internal digital system resources to Port I/O pins on P0, P1, and P2. (See Figure 1.7.) Unlike microcontrollers with standard multiplexed digital I/O, all combinations of functions are supported. The on-board counter/timers, serial buses, HW interrupts, ADC Start of Conversion input, comparator outputs, and other digital signals in the controller can be configured to appear on the Port I/O pins specified in the Crossbar Control registers. This allows the user to select the exact mix of general purpose Port I/O and digital resources needed for his particular application.
Figure 1.7. Digital Crossbar Diagram
Highest Priority SMBus SPI (Internal Digital Signals) UART PCA Comptr. Outputs T0, T1, T2 SYSCLK CNVSTR 8 P0 (P0.0-P0.7) 8 P1 Port Latches P2 (P1.0-P1.7) 8 (P2.0-P2.7) 8 P3 (P3.0-P3.7) P3 I/O Cells P3.0 P3.7 2 4 2 6 2 External Pins XBR0, XBR1, XBR2 Registers PRT0CF, PRT1CF, PRT2CF Registers
Priority Decoder
8 P0 I/O Cells P0.0 P0.7 Highest Priority
6
Digital Crossbar
8
Lowest Priority
P1 I/O Cells
P1.0 P1.7
8
P2 I/O Cells
P2.0 P2.7 Lowest Priority
PRT3CF Register
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
1.5.
PRELIMINARY
Programmable Counter Array
The C8051F018/9 have an on-board Programmable Counter/Timer Array (PCA) in addition to the four 16-bit general-purpose counter/timers. The PCA consists of a dedicated 16-bit counter/timer timebase with 5 programmable capture/compare modules. The timebase gets its clock from one of four sources: the system clock divided by 12, the system clock divided by 4, Timer 0 overflow, or an External Clock Input (ECI). Each capture/compare module can be configured to operate in one of four modes: Edge-Triggered Capture, Software Timer, High Speed Output, or Pulse Width Modulator. The PCA Capture/Compare Module I/O and External Clock Input are routed to the MCU Port I/O via the Digital Crossbar.
Figure 1.8. PCA Block Diagram
System Clock /4 /12 16-Bit Counter/Timer T0 Overflow
Capture/Compare Module 0
Capture/Compare Module 1
Capture/Compare Module 2
Capture/Compare Module 3
Capture/Compare Module 4
CEX0
CEX1
CEX2
CEX3
CEX4
ECI
Crossbar
Port I/O
1.6.
Serial Ports
The C8051F0018/9 include a Full-Duplex UART, SPI Bus, and I2C/SMBus. Each of the serial buses is fully implemented in hardware and makes extensive use of the CIP-51's interrupts, thus requiring very little intervention by the CPU. The serial buses do not "share" resources such as timers, interrupts, or Port I/O, so any or all of the serial buses may be used together.
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CYGNAL Integrated Products, Inc. 2002
Page 15
PRELIMINARY
1.7. Analog to Digital Converter
C8051F018 C8051F019
The C8051F018/9 have an on-chip 10-bit SAR ADC with a 9-channel input multiplexer. With a maximum throughput of 100ksps, the ADC offers true 10-bit accuracy with an INL of 1LSB. The ADC has a maximum throughput of 100ksps. There is also an on-board 15ppm voltage reference, or an external reference may be used via the VREF pin. The ADC is under full control of the CIP-51 microcontroller via the Special Function Registers. One input channel is tied to an internal temperature sensor, while the other eight channels are available externally. Each pair of the eight external input channels can be configured as either two single-ended inputs or a single differential input. The system controller can also put the ADC into shutdown to save power. Conversions can be started in four ways; a software command, an overflow on Timer 2, an overflow on Timer 3, or an external signal input. This flexibility allows the start of conversion to be triggered by software events, external HW signals, or convert continuously. A completed conversion causes an interrupt, or a status bit can be polled in software to determine the end of conversion. The resulting 10-bit data word is latched into two SFRs upon completion of a conversion. The data can be right or left justified in these registers under software control. Compare registers for the ADC data can be configured to interrupt the controller when ADC data is within a specified window. The ADC can monitor a key voltage continuously in background mode, but not interrupt the controller unless the converted data is within the specified window.
Figure 1.9. ADC Diagram
VREF
+ +
AIN0 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7
REF
9-to-1 AMUX + (SE or - DIFF)
+ -
100ksps SAR
ADC
TEMP SENSOR
Control & Data SFR's
SFR Bus
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
1.8. Comparators
PRELIMINARY
The C8051F018/9 have two comparators on chip. The MCU data and control interface to each comparator is via the Special Function Registers. The MCU can individually place each comparator in low power shutdown mode. The comparators have software programmable hysteresis. Each comparator can generate an interrupt on its rising edge, falling edge, or both. The comparators' output state can also be polled in software. These interrupts are capable of waking up the MCU from idle mode. The comparator outputs can be programmed to appear on the Port I/O pins via the Crossbar.
Figure 1.10. Comparator Diagram
CP0
(Port I/O)
CP1 CROSSBAR
(Port I/O)
CP0+ CP0-
+ -
CP0
CP1+ CP1-
+ -
CP0 CP1 SFR's (Data and Cntrl)
CP1
CIP-51 and Interrupt Handler
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
Page 17
PRELIMINARY
2. ABSOLUTE MAXIMUM RATINGS*
C8051F018 C8051F019
Ambient temperature under bias ................................................................................................................ -55 to 125 C Storage Temperature .................................................................................................................................. -65 to 150 C Voltage on any Pin (except VDD and Port I/O) with respect to DGND ....................................-0.3V to (VDD + 0.3V) Voltage on any Port I/O Pin or /RST with respect to DGND.................................................................... -0.3V to 5.8V Voltage on VDD with respect to DGND................................................................................................... -0.3V to 4.2V Maximum Total current through VDD, AV+, DGND and AGND ......................................................................800mA Maximum output current sunk by any Port pin ....................................................................................................100mA Maximum output current sunk by any other I/O pin ..............................................................................................25mA Maximum output current sourced by any Port pin ...............................................................................................100mA Maximum output current sourced by any other I/O pin .........................................................................................25mA *Note: Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the devices at those or any other conditions above those indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability.
3.
GLOBAL DC ELECTRICAL CHARACTERISTICS
MIN 2.8 TYP 3.0 1 5 MAX 3.6 2 20 0.5 2.8 3.0 12.5 0.5 10 5 1.5 -40 +85 3.6 UNITS V mA
A
-40 C to +85 C unless otherwise specified. PARAMETER CONDITIONS Analog Supply Voltage (Note 1) Analog Supply Current Internal REF, ADC, Comparators all active Analog Supply Current with Internal REF, ADC, Comparators all analog sub-systems inactive disabled, oscillator disabled Analog-to-Digital Supply Delta ( | VDD - AV+ | ) Digital Supply Voltage Digital Supply Current with VDD = 2.8V, Clock=25MHz CPU active VDD = 2.8V, Clock=1MHz VDD = 2.8V, Clock=32kHz Digital Supply Current Oscillator not running (shutdown) Digital Supply RAM Data Retention Voltage Specified Operating Temperature Range
V V mA mA A A V
C
Note 1: Analog Supply AV+ must be greater than 1V for VDD monitor to operate.
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
4.
PRELIMINARY
PINOUT AND PACKAGE DEFINITIONS
Table 4.1. Pin Definitions
Type
F018 F019
Name VDD
Description
Digital Voltage Supply.
DGND
31, 40, 62 30, 41, 61 16, 17 5, 15 22 21 28 29 18
23, 32 22, 33, 27, 19 13, 43 44, 12 18 17 20 21 14
Digital Ground.
AV+ AGND TCK TMS TDI TDO XTAL1
Positive Analog Voltage Supply. Analog Ground.
D In D In D In D Out A In
XTAL2 /RST VREF CP0+ CP0CP1+ CP1NC NC AIN0 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7
19 20 6 4 3 2 1 64 63 7 8 9 10 11 12 13 14
15 16 3 2 1 45 46 48 47 4 5 6 7 8 9 10 11
A Out D I/O A I/O A A A A In In In In
A In A In A In A In A In A In A In A In
JTAG Test Clock with internal pull-up. JTAG Test-Mode Select with internal pull-up. JTAG Test Data Input with internal pull-up. TDI is latched on a rising edge of TCK. JTAG Test Data Output with internal pull-up. Data is shifted out on TDO on the falling edge of TCK. TDO output is a tri-state driver. Crystal Input. This pin is the return for the internal oscillator circuit for a crystal or ceramic resonator. For a precision internal clock, connect a crystal or ceramic resonator from XTAL1 to XTAL2. If overdriven by an external CMOS clock, this becomes the system clock. Crystal Output. This pin is the excitation driver for a crystal or ceramic resonator. Chip Reset. Open-drain output of internal Voltage Supply monitor. Is driven low when VDD is < 2.8V. An external source can force a system reset by driving this pin low. Voltage Reference. When configured as an input, this pin is the voltage reference for the MCU. Otherwise, the internal reference drives this pin. Comparator 0 Non-Inverting Input. Comparator 0 Inverting Input. Comparator 1 Non-Inverting Input. Comparator 1 Inverting Input. No Connect Pin. This pin should be left open. No Connect Pin. This pin should be left open. Analog Mux Channel Input 0. (See ADC Specification for complete description). Analog Mux Channel Input 1. (See ADC Specification for complete description). Analog Mux Channel Input 2. (See ADC Specification for complete description). Analog Mux Channel Input 3. (See ADC Specification for complete description). Analog Mux Channel Input 4. (See ADC Specification for complete description). Analog Mux Channel Input 5. (See ADC Specification for complete description). Analog Mux Channel Input 6. (See ADC Specification for complete description). Analog Mux Channel Input 7. (See ADC Specification for complete description).
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PRELIMINARY
Name P0.0 P0.1 P0.2 P0.3 P0.4 P0.5 P0.6 P0.7 P1.0 P1.1 P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 P2.0 P2.1 P2.2 P2.3 P2.4 P2.5 P2.6 P2.7 P3.0 P3.1 P3.2 P3.3 P3.4 P3.5 P3.6 P3.7 Type
F018 F019
C8051F018 C8051F019
Description D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O
Port0 Bit0. Port0 Bit1. Port0 Bit2. Port0 Bit3. Port0 Bit4. Port0 Bit5. Port0 Bit6. Port0 Bit7. Port1 Bit0. Port1 Bit1. Port1 Bit2. Port1 Bit3. Port1 Bit4. Port1 Bit5. Port1 Bit6. Port1 Bit7. Port2 Bit0. Port2 Bit1. Port2 Bit2. Port2 Bit3. Port2 Bit4. Port2 Bit5. Port2 Bit6. Port2 Bit7. Port3 Bit0. Port3 Bit1. Port3 Bit2. Port3 Bit3. Port3 Bit4. Port3 Bit5. Port3 Bit6. Port3 Bit7. (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description). (See the Port I/O Sub-System section for complete description).
39 42 47 48 49 50 55 56 38 37 36 35 34 32 60 59 33 27 54 53 52 51 44 43 26 25 24 23 58 57 46 45
31 34 35 36 37 38 39 40 30 29 28 26 25 24 42 41
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
PRELIMINARY
Figure 4.1. TQFP-64 Pinout Diagram
VDD DGND
P3.4
P3.5 P0.7
P1.6 P1.7
P0.6
P2.2
P2.3
P2.4
P2.5
51
P0.5
50
64
63
NC NC
62
61
60
59
58
57
56
55
54
53
52
49
P0.4
CP1CP1+ CP0CP0+ AGND VREF AIN0 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7 AGND AV+
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
48 47 46 45 44 43 42
P0.3 P0.2 P3.6 P3.7 P2.6 P2.7 P0.1 DGND VDD P0.0 P1.0 P1.1 P1.2 P1.3 P1.4 P2.0
C8051F018
41 40 39 38 37 36 35 34 33
28
29
30
31
17
18
19
20
21
22
23
24
25
26
27
TCK P3.3
AV+
TDI
/RST
TMS
TDO
XTAL1
XTAL2
DGND
P3.2
P3.1
P3.0
P2.1
VDD
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CYGNAL Integrated Products, Inc. 2002
P1.5
32
Page 21
PRELIMINARY
Figure 4.2. TQFP-64 Package Drawing
D D1
C8051F018 C8051F019
MIN NOM MAX (mm) (mm) (mm) A 1.20 0.15 1.05
A1 0.05
E1 E
A2 0.95 b
0.17 0.22 0.27 12.00 10.00 0.50 12.00 10.00 -
64 PIN 1 DESIGNATOR 1 A2 e A b A1
D D1 e E E1
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
PRELIMINARY
Figure 4.3. TQFP-48 Pinout Diagram
CP1+ CP1AGND
P1.6
P1.7
P0.7
P0.6
P0.5
38
48
NC
47
46
45
44
43
42
41
40
39
CP0CP0+ VREF AIN0 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7 AGND
37
P0.4
AV+
NC
1 2 3 4 5 6 7 8 9 10 11 12
36 35 34 33 32
P0.3 P0.2 P0.1 DGND VDD P0.0 P1.0 P1.1 P1.2 DGND P1.3 P1.4
C8051F019
31 30 29 28 27 26 25
13
14
15
16
17
18
19
20
21
22
23
DGND
DGND
TMS
VDD
AV+
XTAL2
XTAL1
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CYGNAL Integrated Products, Inc. 2002
/RST
TDO
P1.5
TCK
TDI
24
Page 23
PRELIMINARY
Figure 4.4. TQFP-48 Package Drawing
D D1
C8051F018 C8051F019
MIN NOM MAX (mm) (mm) (mm) A
E1 E
-
-
1.20 0.15
A1 0.05
A2 0.95 1.00 1.05 b
48 PIN 1 IDENTIFIER A2
0.17 0.22 0.27 9.00 7.00 0.50 9.00 7.00 -
D D1
1 e
e E
A b A1
E1
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
5. ADC
PRELIMINARY
The ADC subsystem consists of a 9-channel configurable analog multiplexer (AMUX) and a 100ksps, 10-bit successive-approximation-register ADC with integrated track-and-hold and programmable window detector (see block diagram in Figure 5.1). The AMUX, PGA, Data Conversion Modes, and Window Detector are all configurable under software control via the Special Function Register's shown in Figure 5.1. The ADC subsystem (ADC, track-and-hold and PGA) is enabled only when the ADCEN bit in the ADC Control register (ADC0CN, Figure 5.7) is set to 1. The ADC subsystem is in low power shutdown when this bit is 0. The Bias Enable bit (BIASE) in the REF0CN register (see Figure 7.2) must be set to 1 in order to supply bias to the ADC.
Figure 5.1. 10-Bit ADC Functional Block Diagram
ADC0GTH ADC0GTL ADC0LTH ADC0LTL
20 AV+ ADCEN 10
ADWINT
COMB LOGIC
AIN0 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7
TEMP SENSOR AGND
+ +
SYSCLK
REF
ADC0H
+
9-to-1 AMUX (SE or - DIFF)
-
10-Bit SAR
10
+ -
ADC
Conversion Start
ADC0L
TMR3 OV T2 OV CNVSTR ADBUSY(w)
AMXAD3 AMXAD2 AMXAD1 AMXAD0
AMX0CF
AMX0SL
ADC0CF
5.1.
Analog Multiplexer
Eight of the AMUX channels are available for external measurements while the ninth channel is internally connected to an on-board temperature sensor (temperature transfer function is shown in Figure 5.3). AMUX input pairs can be programmed to operate in either the differential or single-ended mode. This allows the user to select the best measurement technique for each input channel, and even accommodates mode changes "on-the-fly". The AMUX defaults to all single-ended inputs upon reset. There are two registers associated with the AMUX: the Channel Selection register AMX0SL (Figure 5.5), and the Configuration register AMX0CF (Figure 5.4). The table in Figure 5.5 shows AMUX functionality by channel for each possible configuration.
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
ADCEN ADCTM ADCINT ADBUSY ADSTM1 ADSTM0 ADWINT ADLJST
ADCSC2 ADCSC1 ADCSC0
AIN67IC AIN45IC AIN23IC AIN01IC
ADC0CN
Page 25
PRELIMINARY
5.2. ADC Modes of Operation
C8051F018 C8051F019
The ADC uses VREF to determine its full-scale voltage, thus the reference must be properly configured before performing a conversion (see Section 7). The ADC has a maximum conversion speed of 100ksps. The ADC conversion clock is derived from the system clock. Conversion clock speed can be reduced by a factor of 2, 4, 8 or 16 via the ADCSC bits in the ADC0CF Register. This is useful to adjust conversion speed to accommodate different system clock speeds. A conversion can be initiated in one of four ways, depending on the programmed states of the ADC Start of Conversion Mode bits (ADSTM1, ADSTM0) in ADC0CN. Conversions may be initiated by: 1. Writing a 1 to the ADBUSY bit of ADC0CN; 2. A Timer 3 overflow (i.e. timed continuous conversions); 3. A rising edge detected on the external ADC convert start signal, CNVSTR; 4. A Timer 2 overflow (i.e. timed continuous conversions). Writing a 1 to ADBUSY provides software control of the ADC whereby conversions are performed "on-demand". During conversion, the ADBUSY bit is set to 1 and restored to 0 when conversion is complete. The falling edge of ADBUSY triggers an interrupt (when enabled) and sets the interrupt flag in ADC0CN. Converted data is available in the ADC data word MSB and LSB registers, ADC0H, ADC0L. Converted data can be either left or right justified in the ADC0H:ADC0L register pair (see example in Figure 5.9) depending on the programmed state of the ADLJST bit in the ADC0CN register. The ADCTM bit in register ADC0CN controls the ADC track-and-hold mode. In its default state, the ADC input is continuously tracked, except when a conversion is in progress. Setting ADCTM to 1 allows one of four different low power track-and-hold modes to be specified by states of the ADSTM1-0 bits (also in ADC0CN): 1. Tracking begins with a write of 1 to ADBUSY and lasts for 3 SAR clocks; 2. Tracking starts with an overflow of Timer 3 and lasts for 3 SAR clocks; 3. Tracking is active only when the CNVSTR input is low; 4. Tracking starts with an overflow of Timer 2 and lasts for 3 SAR clocks. Modes 1, 2 and 4 (above) are useful when the start of conversion is triggered with a software command or when the ADC is operated continuously. Mode 3 is used when the start of conversion is triggered by external hardware. In this case, the track-and-hold is in its low power mode at times when the CNVSTR input is high. Tracking can also be disabled (shutdown) when the entire chip is in low power standby or sleep modes.
Figure 5.2. 10-Bit ADC Track and Conversion Example Timing
A. ADC Timing for External Trigger Source
CNVSTR (ADSTM[1:0]=10)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
SAR Clocks ADCTM=1 ADCTM=0
Low Power or Convert
Track
Convert Convert
Low Power Mode Track
Track Or Convert
B. ADC Timing for Internal Trigger Sources
Timer2, Timer3 Overflow; Write 1 to ADBUSY (ADSTM[1:0]=00, 01, 11) SAR Clocks ADCTM=1
Low Power or Convert
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19
Track
1 2 3 4 5 6 7 8 9
Convert
10 11 12 13 14 15 16
Low Power Mode
SAR Clocks ADCTM=0
Track or Convert
Convert
Track
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CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
PRELIMINARY
Figure 5.3. Temperature Sensor Transfer Function
(Volts)
1.000
0.900
0.800 VTEMP = 0.00286(TEMP C) + 0.776
0.700
0.600
0.500 -50 0 50 100
(Celsius)
Figure 5.4. AMX0CF: AMUX Configuration Register
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
Bit7
Bit6
Bit5
Bit4
AIN67IC
Bit3
AIN45IC
Bit2
AIN23IC
Bit1
AIN01IC
Bit0
00000000
SFR Address:
0xBA
Bits7-4: UNUSED. Read = 0000b; Write = don't care Bit3: AIN67IC: AIN6, AIN7 Input Pair Configuration Bit 0: AIN6 and AIN7 are independent singled-ended inputs 1: AIN6, AIN7 are (respectively) +, - differential input pair Bit2: AIN45IC: AIN4, AIN5 Input Pair Configuration Bit 0: AIN4 and AIN5 are independent singled-ended inputs 1: AIN4, AIN5 are (respectively) +, - differential input pair Bit1: AIN23IC: AIN2, AIN3 Input Pair Configuration Bit 0: AIN2 and AIN3 are independent singled-ended inputs 1: AIN2, AIN3 are (respectively) +, - differential input pair Bit0: AIN01IC: AIN0, AIN1 Input Pair Configuration Bit 0: AIN0 and AIN1 are independent singled-ended inputs 1: AIN0, AIN1 are (respectively) +, - differential input pair NOTE: The ADC Data Word is in 2's complement format for channels configured as differential.
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
Page 27
PRELIMINARY
C8051F018 C8051F019
Figure 5.5. AMX0SL: AMUX Channel Select Register (C8051F01x)
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
Bit7
Bit6
Bit5
Bit4
AMXAD3
Bit3
AMXAD2
Bit2
AMXAD1
Bit1
AMXAD0
Bit0
00000000
SFR Address:
0xBB
Bits7-4: UNUSED. Read = 0000b; Write = don't care Bits3-0: AMXAD3-0: AMUX Address Bits 0000-1111: ADC Inputs selected per chart below
0000
A M X 0 C F B I T S 3 0
0001
AIN1
0010
AIN2 AIN2
0011
AIN3 AIN3
AMXAD3-0 0100 0101
AIN4 AIN4 AIN4 AIN4 AIN5 AIN5 AIN5 AIN5
0110
AIN6 AIN6 AIN6 AIN6 AIN6 AIN6 AIN6 AIN6
0111
AIN7 AIN7 AIN7 AIN7 AIN7 AIN7 AIN7 AIN7
1xxx
TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR TEMP SENSOR
0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111
AIN0 +(AIN0) -(AIN1) AIN0 +(AIN0) -(AIN1) AIN0 +(AIN0) -(AIN1) AIN0 +(AIN0) -(AIN1) AIN0 +(AIN0) -(AIN1) AIN0 +(AIN0) -(AIN1) AIN0 +(AIN0) -(AIN1) AIN0 +(AIN0) -(AIN1)
AIN1
+(AIN2) -(AIN3) +(AIN2) -(AIN3)
AIN1
AIN2 AIN2
AIN3 AIN3
+(AIN4) -(AIN5) +(AIN4) -(AIN5) +(AIN4) -(AIN5) +(AIN4) -(AIN5)
AIN1
+(AIN2) -(AIN3) +(AIN2) -(AIN3)
AIN1
AIN2 AIN2
AIN3 AIN3
AIN4 AIN4 AIN4 AIN4
AIN5 AIN5 AIN5 AIN5
+(AIN6) -(AIN7) +(AIN6) -(AIN7) +(AIN6) -(AIN7) +(AIN6) -(AIN7) +(AIN6) -(AIN7) +(AIN6) -(AIN7) +(AIN6) -(AIN7) +(AIN6) -(AIN7)
AIN1
+(AIN2) -(AIN3) +(AIN2) -(AIN3)
AIN1
AIN2 AIN2
AIN3 AIN3
+(AIN4) -(AIN5) +(AIN4) -(AIN5) +(AIN4) -(AIN5) +(AIN4) -(AIN5)
AIN1
+(AIN2) -(AIN3) +(AIN2) -(AIN3)
Page 28
CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
PRELIMINARY
Figure 5.6. ADC0CF: ADC Configuration Register (C8051F01x)
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
ADCSC2
Bit7
ADCSC1
Bit6
ADCSC0
Bit5
Bit4
Bit3
AMPGN2
Bit2
AMPGN1
Bit1
AMPGN0
Bit0
01100000
SFR Address:
0xBC
Bits7-5: ADCSC2-0: ADC SAR Conversion Clock Period Bits 000: SAR Conversion Clock = 1 System Clock 001: SAR Conversion Clock = 2 System Clocks 010: SAR Conversion Clock = 4 System Clocks 011: SAR Conversion Clock = 8 System Clocks 1xx: SAR Conversion Clock = 16 Systems Clocks (Note: Conversion clock should be 2MHz.) Bits4-3: UNUSED. Read = 00b; Write = don't care Bits2-0: Reserved: Must be = 000b
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
Page 29
PRELIMINARY
Figure 5.7. ADC0CN: ADC Control Register
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W Reset Value
ADCEN
Bit7
ADCTM
Bit6
ADCINT
Bit5
ADBUSY
Bit4
ADSTM1
Bit3
ADSTM0
Bit2
ADWINT
Bit1
ADLJST
Bit0
(bit addressable)
00000000
SFR Address:
0xE8
Bit7:
ADCEN: ADC Enable Bit 0: ADC Disabled. ADC is in low power shutdown. 1: ADC Enabled. ADC is active and ready for data conversions. Bit6: ADCTM: ADC Track Mode Bit 0: When the ADC is enabled, tracking is always done unless a conversion is in process 1: Tracking Defined by ADSTM1-0 bits ADSTM1-0: 00: Tracking starts with the write of 1 to ADBUSY and lasts for 3 SAR clocks 01: Tracking started by the overflow of Timer 3 and last for 3 SAR clocks 10: ADC tracks only when CNVSTR input is logic low 11: Tracking started by the overflow of Timer 2 and last for 3 SAR clocks Bit5: ADCINT: ADC Conversion Complete Interrupt Flag (Must be cleared by software) 0: ADC has not completed a data conversion since the last time this flag was cleared 1: ADC has completed a data conversion Bit4: ADBUSY: ADC Busy Bit Read 0: ADC Conversion complete or no valid data has been converted since a reset. The falling edge of ADBUSY generates an interrupt when enabled. 1: ADC Busy converting data Write 0: No effect 1: Starts ADC Conversion if ADSTM1-0 = 00b Bits3-2: ADSTM1-0: ADC Start of Conversion Mode Bits 00: ADC conversion started upon every write of 1 to ADBUSY 01: ADC conversions taken on every overflow of Timer 3 10: ADC conversion started upon every rising edge of CNVSTR 11: ADC conversions taken on every overflow of Timer 2 Bit1: ADWINT: ADC Window Compare Interrupt Flag (Must be cleared by software) 0: ADC Window Comparison Data match has not occurred 1: ADC Window Comparison Data match occurred Bit0: ADLJST: ADC Left Justify Data Bit 0: Data in ADC0H:ADC0L Registers is right justified 1: Data in ADC0H:ADC0L Registers is left justified
Page 30
CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4
PRELIMINARY
R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
Figure 5.8. ADC0H: ADC Data Word MSB Register
00000000
SFR Address:
0xBF
Bits7-0: ADC Data Word Bits For ADLJST = 1: Upper 8-bits of the 10-bit ADC Data Word. For ADLJST = 0: Bits7-2 are the sign extension of Bit1. Bits 1-0 are the upper 2-bits of the 10-bit ADC Data Word.
Figure 5.9. ADC0L: ADC Data Word LSB Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xBE
Bits7-0: ADC Data Word Bits For ADLJST = 1: Bits7-6 are the lower 2-bits of the 10-bit ADC Data Word. Bits5-0 will always read 0. For ADLJST = 0: Bits7-0 are the lower 8-bits of the 10-bit ADC Data Word. NOTE: Resulting 10-bit ADC Data Word appears in the ADC Data Word Registers as follows: ADC0H[1:0]:ADC0L[7:0], if ADLJST = 0 (ADC0H[7:2] will be sign extension of ADC0H.1 if a differential reading, otherwise = 000000b) ADC0H[7:0]:ADC0L[7:6], if ADLJST = 1 (ADC0L[5:0] = 000000b) EXAMPLE: ADC Data Word Conversion Map, AIN0 Input in Single-Ended Mode (AMX0CF=0x00, AMX0SL=0x00) ADC0H:ADC0L ADC0H:ADC0L AIN0 - AGND (Volts) (ADLJST = 0) (ADLJST = 1) REF x (1023/1024) 0x03FF 0xFFC0 REF x 1/2 0x0200 0x8000 REF x (511/1024) 0x01FF 0x7FC0 0 0x0000 0x0000 EXAMPLE: ADC Data Word Conversion Map, AIN0-AIN1 Differential Input Pair (AMX0CF=0x01, AMX0SL=0x00) ADC0H:ADC0L ADC0H:ADC0L AIN0 - AIN1 (Volts) (ADLJST = 0) (ADLJST = 1) REF x (511/512) 0x01FF 0x7FC0 0 0x0000 0x0000 -REF x (1/512) 0xFFFF 0xFFC0 -REF 0xFE00 0x8000
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
Page 31
PRELIMINARY
5.3. ADC Programmable Window Detector
C8051F018 C8051F019
The ADC programmable window detector is very useful in many applications. It continuously compares the ADC output to user-programmed limits and notifies the system when an out-of-band condition is detected. This is especially effective in an interrupt-driven system, saving code space and CPU bandwidth while delivering faster system response times. The window detector interrupt flag (ADWINT in ADC0CN) can also be used in polled mode. The high and low bytes of the reference words are loaded into the ADC Greater-Than and ADC Less-Than registers (ADC0GTH, ADC0GTL, ADC0LTH, and ADC0LTL). Figure 5.14 and Figure 5.15 show example comparisons for reference. Notice that the window detector flag can be asserted when the measured data is inside or outside the user-programmed limits, depending on the programming of the ADC0GTx and ADC0LTx registers.
Figure 5.10. ADC0GTH: ADC Greater-Than Data High Byte Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
11111111
SFR Address:
Bits7-0: The high byte of the ADC Greater-Than Data Word.
0xC5
Figure 5.11. ADC0GTL: ADC Greater-Than Data Low Byte Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
11111111
SFR Address:
0xC4
Bits7-0: The low byte of the ADC Greater-Than Data Word. Definition: ADC Greater-Than Data Word = ADC0GTH:ADC0GTL
Figure 5.12. ADC0LTH: ADC Less-Than Data High Byte Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xC7
Bits7-0: The high byte of the ADC Less-Than Data Word.
Figure 5.13. ADC0LTL: ADC Less-Than Data Low Byte Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xC6
Bits7-0: These bits are the low byte of the ADC Less-Than Data Word. Definition: ADC Less-Than Data Word = ADC0LTH:ADC0LTL
Page 32
CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
Input Voltage (AD0 - AGND) REF x (1023/1024)
PRELIMINARY
Figure 5.14. 10-Bit ADC Window Interrupt Examples, Right Justified Data
ADC Data Word
0x03FF ADWINT not affected 0x0201 REF x (512/1024) 0x0200 0x01FF ADWINT=1 0x0101 REF x (256/1024) 0x0100 0x00FF ADC0GTH:ADC0GTL REF x (256/1024) 0x0101 0x0100 0x00FF ADWINT=1 ADC0LTH:ADC0LTL REF x (512/1024) 0x0201 0x0200 0x01FF ADC0GTH:ADC0GTL ADWINT not affected ADC0LTH:ADC0LTL Input Voltage (AD0 - AGND) REF x (1023/1024)
ADC Data Word
0x03FF ADWINT=1
ADWINT not affected 0 0x0000 0 0x0000
Given: AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 0, ADC0LTH:ADC0LTL = 0x0200, ADC0GTH:ADC0GTL = 0x0100. An ADC End of Conversion will cause an ADC Window Compare Interrupt (ADWINT=1) if the resulting ADC Data Word is < 0x0200 and > 0x0100.
Given: AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 0, ADC0LTH:ADC0LTL = 0x0100, ADC0GTH:ADC0GTL = 0x0200. An ADC End of Conversion will cause an ADC Window Compare Interrupt (ADWINT=1) if the resulting ADC Data Word is < 0x0100 or > 0x0200.
Input Voltage (AD0 - AD1) REF x (511/512)
ADC Data Word
0x01FF ADWINT not affected 0x0101
Input Voltage (AD0 - AD1) REF x (511/512)
ADC Data Word
0x01FF ADWINT=1
0x0101 ADC0LTH:ADC0LTL ADWINT=1 REF x (256/512) 0x0100 0x00FF 0x0000 0xFFFF 0xFFFE ADWINT=1 ADC0GTH:ADC0GTL ADWINT not affected ADC0LTH:ADC0LTL
REF x (256/512)
0x0100 0x00FF 0x0000 0xFFFF 0xFFFE
REF x (-1/512)
ADC0GTH:ADC0GTL
REF x (-1/512)
ADWINT not affected -REF 0xFE00 -REF 0xFE00
Given: AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 0, ADC0LTH:ADC0LTL = 0x0100, ADC0GTH:ADC0GTL = 0xFFFF. An ADC End of Conversion will cause an ADC Window Compare Interrupt (ADWINT=1) if the resulting ADC Data Word is < 0x0100 and > 0xFFFF. (Two's Complement math, 0xFFFF = -1.)
1.2002; Rev. 1.0
Given: AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 0, ADC0LTH:ADC0LTH = 0xFFFF, ADC0GTH:ADC0GTL = 0x0100. An ADC End of Conversion will cause an ADC Window Compare Interrupt (ADWINT=1) if the resulting ADC Data Word is < 0xFFFF or > 0x0100. (Two's Complement math, 0xFFFF = -1.)
Page 33
CYGNAL Integrated Products, Inc. 2002
PRELIMINARY
C8051F018 C8051F019
ADC Data Word
0xFFC0 ADWINT=1
Figure 5.15. 10-Bit ADC Window Interrupt Examples, Left Justified Data
Input Voltage (AD0 - AGND) REF x (1023/1024)
ADC Data Word
0xFFC0 ADWINT not affected 0x8040
Input Voltage (AD0 - AGND) REF x (1023/1024)
0x8040 ADC0LTH:ADC0LTL ADWINT=1 REF x (512/1024) 0x8000 0x7FC0 0x4040 ADC0GTH:ADC0GTL REF x (256/1024) 0x4000 0x3FC0 ADWINT=1 ADC0GTH:ADC0GTL ADWINT not affected ADC0LTH:ADC0LTL
REF x (512/1024)
0x8000 0x7FC0 0x4040
REF x (256/1024)
0x4000 0x3FC0
ADWINT not affected 0 0x0000 0 0x0000
Given: AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 1, ADC0LTH:ADC0LTL = 0x8000, ADC0GTH:ADC0GTL = 0x4000. An ADC End of Conversion will cause an ADC Window Compare Interrupt (ADWINT=1) if the resulting ADC Data Word is < 0x8000 and > 0x4000.
Given: AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 1, ADC0LTH:ADC0LTL = 0x4000, ADC0GTH:ADC0GTL = 0x8000. An ADC End of Conversion will cause an ADC Window Compare Interrupt (ADWINT=1) if the resulting ADC Data Word is < 0x4000 or > 0x8000.
Input Voltage (AD0 - AD1) REF x (511/512)
ADC Data Word
0x7FC0 ADWINT not affected 0x2040
Input Voltage (AD0 - AD1) REF x (511/512)
ADC Data Word
0x7FC0 ADWINT=1
0x2040 ADC0LTH:ADC0LTL ADWINT=1 REF x (128/512) 0x2000 0x1FC0 0x0000 ADC0GTH:ADC0GTL REF x (-1/512) 0xFFC0 0xFF80 ADWINT=1 ADC0GTH:ADC0GTL ADWINT not affected ADC0LTH:ADC0LTL
REF x (128/512)
0x2000 0x1FC0 0x0000
REF x (-1/512)
0xFFC0 0xFF80
ADWINT not affected -REF 0x8000 -REF 0x8000
Given: AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 1, ADC0LTH:ADC0LTL = 0x2000, ADC0GTH:ADC0GTL = 0xFFC0. An ADC End of Conversion will cause an ADC Window Compare Interrupt (ADWINT=1) if the resulting ADC Data Word is < 0x2000 and > 0xFFC0. (Two's Complement math.)
Page 34
Given: AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 1, ADC0LTH:ADC0LTH = 0xFFC0, ADC0GTH:ADC0GTL = 0x2000. An ADC End of Conversion will cause an ADC Window Compare Interrupt (ADWINT=1) if the resulting ADC Data Word is < 0xFFC0 or > 0x2000. (Two's Complement math.)
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
C8051F018 C8051F019
PRELIMINARY
Table 5.1. 10-Bit ADC Electrical Characteristics
VDD = 3.0V, AV+ = 3.0V, VREF = 2.40V (REFBE=0), -40 C to +85 C unless otherwise specified. PARAMETER CONDITIONS MIN TYP MAX DC ACCURACY Resolution 10 Integral Nonlinearity 1/2 1 Differential Nonlinearity Guaranteed Monotonic 1/2 1 Offset Error 0.5 Full Scale Error Differential mode -1.5 0.5 Offset Temperature 0.25 Coefficient DYNAMIC PERFORMANCE (10kHz sine-wave input, 0 to -1dB of full scale, 100ksps) Signal-to-Noise Plus 59 61 Distortion Total Harmonic Distortion Up to the 5th harmonic -70 Spurious-Free Dynamic 80 Range CONVERSION RATE Conversion Time in SAR 16 Clocks SAR Clock Frequency 2.5 Track/Hold Acquisition Time Throughput Rate ANALOG INPUTS Voltage Conversion Range 1.5 100 Single-ended Mode (AINn - AGND) Differential Mode |(AINn+) - (AINm-)| Any AINn pin 0 AGND 10
0.20 3 2.86 33.5 776 8.51
UNITS bits LSB LSB LSB LSB ppm/ C dB dB dB
clocks MHz MHz s ksps V V pF
C C mV/ C V/ C mV mV
Input Voltage Input Capacitance TEMPERATURE SENSOR Linearity Absolute Accuracy Gain Gain Error (1) Offset Temp = 0 C Offset Error (1) Temp = 0 C POWER SPECIFICATIONS Power Supply Current (AV+ Operating Mode, 100ksps supplied to ADC) Power Supply Rejection
VREF - 1LSB AV+
450
0.3
900
A
mV/V
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
Page 35
PRELIMINARY
6. COMPARATORS
C8051F018 C8051F019
The C8051F018/9 have two on-chip analog voltage comparators as shown in Figure 6.1. The inputs of each Comparator are available at the package pins. The output of each comparator is optionally available at the package pins via the I/O crossbar (see Section 13.1). When assigned to package pins, each comparator output can be programmed to operate in open drain or push-pull modes (see section 13.3). The hysteresis of each comparator is software-programmable via its respective Comparator control register (CPT0CN, CPT1CN). The user can program both the amount of hysteresis voltage (referred to the input voltage) and the positive and negative-going symmetry of this hysteresis around the threshold voltage. The output of the comparator can be polled in software, or can be used as an interrupt source. Each comparator can be individually enabled or disabled (shutdown). When disabled, the comparator output (if assigned to a Port I/O pin via the Crossbar) defaults to the logic low state, its interrupt capability is suspended and its supply current falls to less than 1A. Comparator 0 inputs can be externally driven from -0.25V to (AV+) + 0.25V without damage or upset. The Comparator 0 hysteresis is programmed using bits 3-0 in the Comparator 0 Control Register CPT0CN (shown in Figure 6.3). The amount of negative hysteresis voltage is determined by the settings of the CP0HYN bits. As shown in Figure 6.2, settings of 10, 4 or 2mV of negative hysteresis can be programmed, or negative hysteresis can be disabled. In a similar way, the amount of positive hysteresis is determined by the setting the CP0HYP bits. Comparator interrupts can be generated on both rising-edge and falling-edge output transitions. (For Interrupt enable and priority control, see Section 8.4). The CP0FIF flag is set upon a Comparator 0 falling-edge interrupt, and the CP0RIF flag is set upon the Comparator 0 rising-edge interrupt. Once set, these bits remain set until cleared by the CPU. The Output State of Comparator 0 can be obtained at any time by reading the CP0OUT bit. Note the comparator output and interrupt should be ignored until the comparator settles after power-up. Comparator 0 is enabled by setting the CP0EN bit, and is disabled by clearing this bit. Note there is a 20usec settling time for the comparator output to stabilize after setting the CP0EN bit or a power-up. Comparator 0 can also be programmed as a reset source. For details, see Section 11. The operation of Comparator 1 is identical to that of Comparator 0, except the Comparator 1 is controlled by the CPT1CN Register (Figure 6.4). Comparator 1 can not be programmed as a reset source. The complete electrical specifications for the Comparators are given in Table 6.1.
Figure 6.1. Comparator Functional Block Diagram
CP0EN CP0OUT
CPT0CN
CP0RIF CP0FIF CP0HYP1 CP0HYP0 CP0HYN1 CP0HYN0
AV+
Reset Decision Tree
CP0+ CP0-
+
D
SET
Q Q
D
SET
Q Q
Crossbar Interrupt Handler
CP1EN AGND
CLR
CLR
(SYNCHRONIZER)
CPT1CN
CP1OUT CP1RIF CP1FIF CP1HYP1 CP1HYP0 CP1HYN1 CP1HYN0
AV+
CP1+ CP1-
+
D
SET
Q Q
D
SET
Q Q
Crossbar Interrupt Handler
AGND
CLR
CLR
(SYNCHRONIZER)
Page 36
CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
PRELIMINARY
Figure 6.2. Comparator Hysteresis Plot
VIN+ VIN-
CP0+ CP0-
+ CP0 _ OUT
CIRCUIT CONFIGURATION
Positive Hysteresis Voltage (Programmed with CP0HYSP Bits)
INPUTS
VINNegative Hysteresis Voltage (Programmed by CP0HYSN Bits)
VIN+
VOH
OUTPUT
VOL
Negative Hysteresis Disabled Positive Hysteresis Disabled Maximum Positive Hysteresis Maximum Negative Hysteresis
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
Page 37
PRELIMINARY
R/W R R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W Reset Value
Figure 6.3. CPT0CN: Comparator 0 Control Register
CP0EN
Bit7
CP0OUT
Bit6
CP0RIF
Bit5
CP0FIF
Bit4
CP0HYP1
Bit3
CP0HYP0
Bit2
CP0HYN1
Bit1
CP0HYN0
Bit0
00000000
SFR Address:
0x9E
Bit7:
CP0EN: Comparator 0 Enable Bit 0: Comparator 0 Disabled. 1: Comparator 0 Enabled. Bit6: CP0OUT: Comparator 0 Output State Flag 0: Voltage on CP0+ < CP01: Voltage on CP0+ > CP0Bit5: CP0RIF: Comparator 0 Rising-Edge Interrupt Flag 0: No Comparator 0 Rising-Edge Interrupt has occurred since this flag was cleared 1: Comparator 0 Rising-Edge Interrupt has occurred since this flag was cleared Bit4: CP0FIF: Comparator 0 Falling-Edge Interrupt Flag 0: No Comparator 0 Falling-Edge Interrupt has occurred since this flag was cleared 1: Comparator 0 Falling-Edge Interrupt has occurred since this flag was cleared Bit3-2: CP0HYP1-0: Comparator 0 Positive Hysteresis Control Bits 00: Positive Hysteresis Disabled 01: Positive Hysteresis = 2mV 10: Positive Hysteresis = 4mV 11: Positive Hysteresis = 10mV Bit1-0: CP0HYN1-0: Comparator 0 Negative Hysteresis Control Bits 00: Negative Hysteresis Disabled 01: Negative Hysteresis = 2mV 10: Negative Hysteresis = 4mV 11: Negative Hysteresis = 10mV
Page 38
CYGNAL Integrated Products, Inc. 2002
1.2002; Rev. 1.0
C8051F018 C8051F019
PRELIMINARY
Figure 6.4. CPT1CN: Comparator 1 Control Register
R/W R R/W R/W R/W R/W R/W R/W Reset Value
CP1EN
Bit7
CP1OUT
Bit6
CP1RIF
Bit5
CP1FIF
Bit4
CP1HYP1
Bit3
CP1HYP0
Bit2
CP1HYN1
Bit1
CP1HYN0
Bit0
00000000
SFR Address:
0x9F
Bit7:
CP1EN: Comparator 1 Enable Bit 0: Comparator 1 Disabled. 1: Comparator 1 Enabled. Bit6: CP1OUT: Comparator 1 Output State Flag 0: Voltage on CP1+ < CP11: Voltage on CP1+ > CP1Bit5: CP1RIF: Comparator 1 Rising-Edge Interrupt Flag 0: No Comparator 1 Rising-Edge Interrupt has occurred since this flag was cleared 1: Comparator 1 Rising-Edge Interrupt has occurred since this flag was cleared Bit4: CP1FIF: Comparator 1 Falling-Edge Interrupt Flag 0: No Comparator 1 Falling-Edge Interrupt has occurred since this flag was cleared 1: Comparator 1 Falling-Edge Interrupt has occurred since this flag was cleared Bit3-2: CP1HYP1-0: Comparator 1 Positive Hysteresis Control Bits 00: Positive Hysteresis Disabled 01: Positive Hysteresis = 2mV 10: Positive Hysteresis = 4mV 11: Positive Hysteresis = 10mV Bit1-0: CP1HYN1-0: Comparator 1 Negative Hysteresis Control Bits 00: Negative Hysteresis Disabled 01: Negative Hysteresis = 2mV 10: Negative Hysteresis = 4mV 11: Negative Hysteresis = 10mV
1.2002; Rev. 1.0
CYGNAL Integrated Products, Inc. 2002
Page 39
PRELIMINARY
Table 6.1. Comparator Electrical Characteristics
VDD = 3.0V, AV+ = 3.0V, -40 C to +85 C unless otherwise specified. PARAMETER CONDITIONS Response Time1 (CP+) - (CP-) = 100mV (Note 1) Response Time2 (CP+) - (CP-) = 10mV (Note 1) Common Mode Rejection Ratio Positive Hysteresis1 CPnHYP1-0 = 00 Positive Hysteresis2 CPnHYP1-0 = 01 Positive Hysteresis3 CPnHYP1-0 = 10 Positive Hysteresis4 CPnHYP1-0 = 11 Negative Hysteresis1 CPnHYN1-0 = 00 Negative Hysteresis2 CPnHYN1-0 = 01 Negative Hysteresis3 CPnHYN1-0 = 10 Negative Hysteresis4 CPnHYN1-0 = 11 Inverting or Non-inverting Input Voltage Range Input Capacitance Input Bias Current Input Offset Voltage POWER SUPPLY Power-up Time CPnEN from 0 to 1 Power Supply Rejection Supply Current Operating Mode (each comparator) at DC Note 1: CPnHYP1-0 = CPnHYN1-0 = 00. MIN
C8051F018 C8051F019
TYP 4 12 1.5 0 4.5 9 17 0 4.5 9 17
MAX
4 1 7 13 25 1 7 13 25 (AV+) + 0.25 +5 +10
UNITS s s mV/V mV mV mV mV mV mV mV mV V pF nA mV
s mV/V A
2 4 10 2 4 10 -0.25
-5 -10
7 0.001
20 0.1 1.5
1 10
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7. VOLTAGE REFERENCE
PRELIMINARY
The voltage reference circuit consists of a 1.2V, 15ppm/ C (typical) bandgap voltage reference generator and a gainof-two output buffer amplifier. The reference voltage on VREF can be connected to external devices in the system, as long as the maximum load seen by the VREF pin is less than 200A to AGND (see Figure 7.1). If a different reference voltage is required, an external reference can be connected to the VREF pin and the internal bandgap and buffer amplifier disabled in software. The external reference voltage must still be less than AV+ -0.3V. The Reference Control Register, REF0CN (defined in Figure 7.2), provides the means to enable or disable the bandgap and buffer amplifier. The BIASE bit in REF0CN enables the bias circuitry for the ADC while the REFBE bit enables the bandgap reference and buffer amplifier which drive the VREF pin. When disabled, the supply current drawn by the bandgap and buffer amplifier falls to less than 1A (typical) and the output of the buffer amplifier enters a high impedance state. If the internal bandgap is used as the reference voltage generator, BIASE and REFBE must both be set to 1. If an external reference is used, REFBE must be set to 0 and BIASE must be set to 1. If the ADC is not being used, both of these bits can be set to 0 to conserve power. The electrical specifications for the Voltage Reference are given in Table 7.1. The temperature sensor connects to the highest order input of the A/D converter's input multiplexer. The TEMPE bit within REF0CN enables and disables the temperature sensor. While disabled, the temperature sensor defaults to a high impedance state and any A/D measurements performed on the sensor while disabled result in meaningless data.
Figure 7.1. Voltage Reference Functional Block Diagram
AV+ External Voltage Reference Circuit
EN
R1
REF0CN
Temp Sensor
(to Analog Mux)
TEMPE BIASE REFBE
EN
Bias Generator
AGND
(Bias to ADC)
AGND
VREF
External Equivalent Load Circuit
EN
2.4V Reference
AGND
(to ADC)
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PRELIMINARY
Figure 7.2. REF0CN: Reference Control Register
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W Reset Value
Bit7
Bit6
Bit5
Bit4
Bit3
TEMPE
Bit2
BIASE
Bit1
REFBE
Bit0
00000000
SFR Address:
0xD1
Bits7-3: UNUSED. Read = 00000b; Write = don't care Bit2: TEMPE: Temperature Sensor Enable Bit 0: Internal Temperature Sensor Off. 1: Internal Temperature Sensor On. Bit1: BIASE: Bias Enable Bit for ADC 0: Internal Bias Off. 1: Internal Bias On (required for use of ADC). Bit0: REFBE: Internal Voltage Reference Buffer Enable Bit 0: Internal Reference Buffer Off. System reference can be driven from external source on VREF pin. 1: Internal Reference Buffer On. System reference provided by internal voltage reference.
Table 7.1. Reference Electrical Characteristics
VDD = 3.0V, AV+ = 3.0V, -40 C to +85 C unless otherwise specified. PARAMETER CONDITIONS INTERNAL REFERENCE (REFBE = 1) Output Voltage 25 C ambient VREF Short Circuit Current VREF Temperature Coefficient Load Regulation Load = (0-to-200A) to AGND (Note 1) VREF Turn-on Time1 4.7F tantalum, 0.1F ceramic bypass VREF Turn-on Time2 0.1F ceramic bypass VREF Turn-on Time3 no bypass cap EXTERNAL REFERENCE (REFBE = 0) Input Voltage Range Input Current MIN 2.34 TYP 2.43 15 0.5 2 20 10 1.00 0 (AV+) - 0.3V 1 MAX 2.50 30 UNITS V mA ppm/ C ppm/A ms s s V
A
Note 1: The reference can only source current. When driving an external load, it is recommended to add a load resistor to AGND.
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8. CIP-51 CPU
PRELIMINARY
The MCUs' system CPU is the CIP-51. The CIP-51 is fully compatible with the MCS-51TM instruction set. Standard 803x/805x assemblers and compilers can be used to develop software. The MCU family has a superset of all the peripherals included with a standard 8051. Included are four 16-bit counter/timers (see description in Section 17), a full-duplex UART (see description in Section 16), 256 bytes of internal RAM, 128 byte Special Function Register (SFR) address space (see Section 8.3), and four byte-wide I/O Ports (see description in Section 12). The CIP-51 also includes on-chip debug hardware (see description in Section 19), and interfaces directly with the MCUs' analog and digital subsystems providing a complete data acquisition or control-system solution in a single integrated circuit. Features The CIP-51 Microcontroller core implements the standard 8051 organization and peripherals as well as additional custom peripherals and functions to extend its capability (see Figure 8.1 for a block diagram). The CIP-51 includes the following features: Fully Compatible with MCS-51 Instruction Set 25 MIPS Peak Throughput with 25MHz Clock 0 to 25MHz Clock Frequency Four Byte-Wide I/O Ports Extended Interrupt Handler Reset Input Power Management Modes On-chip Debug Circuitry Program and Data Memory Security
Figure 8.1. CIP-51 Block Diagram
DATA BUS
D8 D8 D8 D8 D8
ACCUMULATOR
B REGISTER
STACK POINTER
DATA BUS
TMP1
TMP2
PSW
ALU
D8 D8
SRAM ADDRESS REGISTER
D8
SRAM (256 X 8)
D8
DATA BUS
SFR_ADDRESS BUFFER
D8
DATA POINTER
D8 D8
SFR BUS INTERFACE
SFR_CONTROL SFR_WRITE_DATA SFR_READ_DATA
PC INCREMENTER
DATA BUS
PROGRAM COUNTER (PC)
D8
MEM_ADDRESS MEM_CONTROL MEMORY INTERFACE
PRGM. ADDRESS REG.
A16
MEM_WRITE_DATA MEM_READ_DATA
PIPELINE RESET CLOCK STOP IDLE POWER CONTROL REGISTER
D8
D8
CONTROL LOGIC INTERRUPT INTERFACE
SYSTEM_IRQs
D8
EMULATION_IRQ
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PRELIMINARY
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Performance The CIP-51 employs a pipelined architecture that greatly increases its instruction throughput over the standard 8051 architecture. In a standard 8051, all instructions except for MUL and DIV take 12 or 24 system clock cycles to execute, and usually have a maximum system clock of 12MHz. By contrast, the CIP-51 core executes 70% of its instructions in one or two system clock cycles, with no instructions taking more than eight system clock cycles. With the CIP-51's maximum system clock at 25MHz, it has a peak throughput of 25MIPS. The CIP-51 has a total of 109 instructions. The number of instructions versus the system clock cycles required to execute them is as follows: Instructions Clocks to Execute 26 1 50 2 5 2/3 14 3 7 3/4 3 4 1 4/5 2 5 1 8
Programming and Debugging Support A JTAG-based serial interface is provided for in-system programming of the Flash program memory and communication with on-chip debug support circuitry. The reprogrammable Flash can also be read and changed a single byte at a time by the application software using the MOVC and MOVX instructions. This feature allows program memory to be used for non-volatile data storage as well as updating program code under software control. The on-chip debug support circuitry facilitates full speed in-circuit debugging, allowing the setting of hardware breakpoints and watch points, starting, stopping and single stepping through program execution (including interrupt service routines), examination of the program's call stack, and reading/writing the contents of registers and memory. This method of on-chip debugging is completely non-intrusive and non-invasive, requiring no RAM, Stack, timers, or other on-chip resources. The CIP-51 is supported by development tools from Cygnal Integrated Products and third party vendors. Cygnal provides an integrated development environment (IDE) including editor, macro assembler, debugger and programmer. The IDE's debugger and programmer interface to the CIP-51 via its JTAG interface to provide fast and efficient in-system device programming and debugging. Third party macro assemblers and C compilers are also available.
8.1.
INSTRUCTION SET
The instruction set of the CIP-51 System Controller is fully compatible with the standard MCS-51TM instruction set. Standard 8051 development tools can be used to develop software for the CIP-51. All CIP-51 instructions are the binary and functional equivalent of their MCS-51TM counterparts, including opcodes, addressing modes and effect on PSW flags. However, instruction timing is different than that of the standard 8051.
8.1.1.
Instruction and CPU Timing
In many 8051 implementations, a distinction is made between machine cycles and clock cycles, with machine cycles varying from 2 to 12 clock cycles in length. However, the CIP-51 implementation is based solely on clock cycle timing. All instruction timings are specified in terms of clock cycles. Due to the pipelined architecture of the CIP-51, most instructions execute in the same number of clock cycles as there are program bytes in the instruction. Conditional branch instructions take one less clock cycle to complete when the branch is not taken as opposed to when the branch is taken. Table 8.1 is the CIP-51 Instruction Set Summary, which includes the mnemonic, number of bytes, and number of clock cycles for each instruction.
8.1.2.
MOVX Instruction and Program Memory
The MOVX instruction is typically used to access external data memory. In the CIP-51, the MOVX instruction can access the on-chip program memory space implemented as reprogrammable Flash memory using the control bits in the PSCTL register (see Figure 9.1). This feature provides a mechanism for the CIP-51 to update program code and use the program memory space for non-volatile data storage. MOVX is still used to read/write this external RAM with the PSCTL register configured for accessing the external data memory space. Refer to Section 9 (Flash Memory) for further details.
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Table 8.1. CIP-51 Instruction Set Summary
Mnemonic ADD A,Rn ADD A,direct ADD A,@Ri ADD A,#data ADDC A,Rn ADDC A,direct ADDC A,@Ri ADDC A,#data SUBB A,Rn SUBB A,direct SUBB A,@Ri SUBB A,#data INC A INC Rn INC direct INC @Ri DEC A DEC Rn DEC direct DEC @Ri INC DPTR MUL AB DIV AB DA A ANL A,Rn ANL A,direct ANL A,@Ri ANL A,#data ANL direct,A ANL direct,#data ORL A,Rn ORL A,direct ORL A,@Ri ORL A,#data ORL direct,A ORL direct,#data XRL A,Rn XRL A,direct XRL A,@Ri XRL A,#data XRL direct,A XRL direct,#data CLR A CPL A RL A RLC A
Description ARITHMETIC OPERATIONS Add register to A Add direct byte to A Add indirect RAM to A Add immediate to A Add register to A with carry Add direct byte to A with carry Add indirect RAM to A with carry Add immediate to A with carry Subtract register from A with borrow Subtract direct byte from A with borrow Subtract indirect RAM from A with borrow Subtract immediate from A with borrow Increment A Increment register Increment direct byte Increment indirect RAM Decrement A Decrement register Decrement direct byte Decrement indirect RAM Increment Data Pointer Multiply A and B Divide A by B Decimal Adjust A LOGICAL OPERATIONS AND Register to A AND direct byte to A AND indirect RAM to A AND immediate to A AND A to direct byte AND immediate to direct byte OR Register to A OR direct byte to A OR indirect RAM to A OR immediate to A OR A to direct byte OR immediate to direct byte Exclusive-OR Register to A Exclusive-OR direct byte to A Exclusive-OR indirect RAM to A Exclusive-OR immediate to A Exclusive-OR A to direct byte Exclusive-OR immediate to direct byte Clear A Complement A Rotate A left Rotate A left through carry
Bytes 1 2 1 2 1 2 1 2 1 2 1 2 1 1 2 1 1 1 2 1 1 1 1 1 1 2 1 2 2 3 1 2 1 2 2 3 1 2 1 2 2 3 1 1 1 1
Clock Cycles 1 2 2 2 1 2 2 2 1 2 2 2 1 1 2 2 1 1 2 2 1 4 8 1 1 2 2 2 2 3 1 2 2 2 2 3 1 2 2 2 2 3 1 1 1 1
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Mnemonic RR A RRC A SWAP A MOV A,Rn MOV A,direct MOV A,@Ri MOV A,#data MOV Rn,A MOV Rn,direct MOV Rn,#data MOV direct,A MOV direct,Rn MOV direct,direct MOV direct,@Ri MOV direct,#data MOV @Ri,A MOV @Ri,direct MOV @Ri,#data MOV DPTR,#data16 MOVC A,@A+DPTR MOVC A,@A+PC MOVX A,@Ri MOVX @Ri,A MOVX A,@DPTR MOVX @DPTR,A PUSH direct POP direct XCH A,Rn XCH A,direct XCH A,@Ri XCHD A,@Ri CLR C CLR bit SETB C SETB bit CPL C CPL bit ANL C,bit ANL C,/bit ORL C,bit ORL C,/bit MOV C,bit MOV bit,C JC rel JNC rel JB bit,rel JNB bit,rel JBC bit,rel Description Rotate A right Rotate A right through carry Swap nibbles of A DATA TRANSFER Move register to A Move direct byte to A Move indirect RAM to A Move immediate to A Move A to register Move direct byte to register Move immediate to register Move A to direct byte Move register to direct byte Move direct byte to direct Move indirect RAM to direct byte Move immediate to direct byte Move A to indirect RAM Move direct byte to indirect RAM Move immediate to indirect RAM Load data pointer with 16-bit constant Move code byte relative DPTR to A Move code byte relative PC to A Move external data (8-bit address) to A Move A to external data (8-bit address) Move external data (16-bit address) to A Move A to external data (16-bit address) Push direct byte onto stack Pop direct byte from stack Exchange register with A Exchange direct byte with A Exchange indirect RAM with A Exchange low nibble of indirect RAM with A BOOLEAN MANIPULATION Clear carry Clear direct bit Set carry Set direct bit Complement carry Complement direct bit AND direct bit to carry AND complement of direct bit to carry OR direct bit to carry OR complement of direct bit to carry Move direct bit to carry Move carry to direct bit Jump if carry is set Jump if carry not set Jump if direct bit is set Jump if direct bit is not set Jump if direct bit is set and clear bit
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Bytes 1 1 1 1 2 1 2 1 2 2 2 2 3 2 3 1 2 2 3 1 1 1 1 1 1 2 2 1 2 1 1 1 2 1 2 1 2 2 2 2 2 2 2 2 2 3 3 3 Clock Cycles 1 1 1 1 2 2 2 1 2 2 2 2 3 2 3 2 2 2 3 3 3 3 3 3 3 2 2 1 2 2 2 1 2 1 2 1 2 2 2 2 2 2 2 2/3 2/3 3/4 3/4 3/4
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Mnemonic ACALL addr11 LCALL addr16 RET RETI AJMP addr11 LJMP addr16 SJMP rel JMP @A+DPTR JZ rel JNZ rel CJNE A,direct,rel CJNE A,#data,rel CJNE Rn,#data,rel CJNE @Ri,#data,rel DJNZ Rn,rel DJNZ direct,rel NOP
PRELIMINARY
Description PROGRAM BRANCHING Absolute subroutine call Long subroutine call Return from subroutine Return from interrupt Absolute jump Long jump Short jump (relative address) Jump indirect relative to DPTR Jump if A equals zero Jump if A does not equal zero Compare direct byte to A and jump if not equal Compare immediate to A and jump if not equal Compare immediate to register and jump if not equal Compare immediate to indirect and jump if not equal Decrement register and jump if not zero Decrement direct byte and jump if not zero No operation Bytes 2 3 1 1 2 3 2 1 2 2 3 3 3 3 2 3 1 Clock Cycles 3 4 5 5 3 4 3 3 2/3 2/3 3/4 3/4 3/4 4/5 2/3 3/4 1
Notes on Registers, Operands and Addressing Modes: Rn - Register R0-R7 of the currently selected register bank. @Ri - Data RAM location addressed indirectly through register R0-R1 rel - 8-bit, signed (two's compliment) offset relative to the first byte of the following instruction. Used by SJMP and all conditional jumps. direct - 8-bit internal data location's address. This could be a direct-access Data RAM location (0x00-0x7F) or an SFR (0x80-0xFF). #data - 8-bit constant #data 16 - 16-bit constant bit - Direct-addressed bit in Data RAM or SFR. addr 11 - 11-bit destination address used by ACALL and AJMP. The destination must be within the same 2K-byte page of program memory as the first byte of the following instruction. addr 16 - 16-bit destination address used by LCALL and LJMP. The destination may be anywhere within the 64K-byte program memory space.
There is one unused opcode (0xA5) that performs the same function as NOP. All mnemonics copyrighted (c) Intel Corporation 1980.
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8.2. MEMORY ORGANIZATION
C8051F018 C8051F019
The memory organization of the CIP-51 System Controller is similar to that of a standard 8051. There are two separate memory spaces: program memory and data memory. Program and data memory share the same address space but are accessed via different instruction types. There are 256 bytes of internal data memory and 64K bytes of internal program memory address space implemented within the CIP-51. The CIP-51 memory organization is shown in Figure 8.2.
8.2.1.
Program Memory
The CIP-51 has a 64K-byte program memory space. The MCU implements 16k + 128 bytes of this program memory space as in-system, reprogrammable Flash memory, organized in a contiguous block from addresses 0x0000 to 0x3FFF. Note: 512 bytes (0x3E00 - 0x3FFF) of this memory are reserved for factory use and are not available for user program storage. The 128 byte block is located at addresses 0x8000 - 0x807F. Program memory is normally assumed to be read-only. However, the CIP-51 can write to program memory by setting the Program Store Write Enable bit (PSCTL.0) and using the MOVX instruction. This feature provides a mechanism for the CIP-51 to update program code and use the program memory space for non-volatile data storage. Refer to Section 9 (Flash Memory) for further details.
8.2.2.
Data Memory
The CIP-51 implements 256 bytes of internal RAM mapped into the data memory space from 0x00 through 0xFF. The lower 128 bytes of data memory are used for general purpose registers and scratch pad memory. Either direct or indirect addressing may be used to access the lower 128 bytes of data memory. Locations 0x00 through 0x1F are addressable as four banks of general purpose registers, each bank consisting of eight byte-wide registers. The next 16 bytes, locations 0x20 through 0x2F, may be addressed as bytes or as 128 bit locations accessible with the direct-bit addressing mode. The upper 128 bytes of data memory are accessible only by indirect addressing. This region occupies the same address space as the Special Function Registers (SFR) but is physically separate from the SFR space. The addressing mode used by an instruction when accessing locations above 0x7F determines whether the CPU accesses the upper 128 bytes of data memory space or the SFRs. Instructions that use direct addressing will access the SFR space. Instructions using indirect addressing above 0x7F will access the upper 128 bytes of data memory. Figure 8.2 illustrates the data memory organization of the CIP-51. The C8051F018/9 also have 1024 bytes of RAM in the external data memory space of the CIP-51, accessible using the MOVX instruction. Refer to Section 10 (External RAM) for details.
8.2.3.
General Purpose Registers
The lower 32 bytes of data memory, locations 0x00 through 0x1F, may be addressed as four banks of generalpurpose registers. Each bank consists of eight byte-wide registers designated R0 through R7. Only one of these banks may be enabled at a time. Two bits in the program status word, RS0 (PSW.3) and RS1 (PSW.4), select the active register bank (see description of the PSW in Figure 8.6). This allows fast context switching when entering subroutines and interrupt service routines. Indirect addressing modes use registers R0 and R1 as index registers.
8.2.4.
Bit Addressable Locations
In addition to direct access to data memory organized as bytes, the sixteen data memory locations at 0x20 through 0x2F are also accessible as 128 individually addressable bits. Each bit has a bit address from 0x00 to 0x7F. Bit 0 of the byte at 0x20 has bit address 0x00 while bit 7 of the byte at 0x20 has bit address 0x07. Bit 7 of the byte at 0x2F has bit address 0x7F. A bit access is distinguished from a full byte access by the type of instruction used (bit source or destination operands as opposed to a byte source or destination). The MCS-51TM assembly language allows an alternate notation for bit addressing of the form XX.B where XX is the byte address and B is the bit position within the byte. For example, the instruction: MOV C, 22h.3 moves the Boolean value at 0x13 (bit 3 of the byte at location 0x22) into the user Carry flag.
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Figure 8.2. Memory Map
PROGRAM MEMORY
0x807F 0x8000 0x7FFF 0x3E00 0x3DFF FLASH (In-System Programmable) RESERVED 0xFF 0x80 0x7F
DATA MEMORY INTERNAL DATA ADDRESS SPACE
Upper 128 RAM (Indirect Addressing Only) (Direct and Indirect Addressing) Special Function Register's (Direct Addressing Only)
FLASH (In-System Programmable in 512 Byte Sectors) 0x0000
0x30 0x2F 0x20 0x1F 0x00
Bit Addressable General Purpose Registers
Lower 128 RAM (Direct and Indirect Addressing)
EXTERNAL DATA ADDRESS SPACE
0xFFFF (same 1024 byte RAM block ) 0xFC00
0x0BFF
0x0800 0x07FF (same 1024 byte RAM block ) 0x0400 0x03FF 0x0000
(same 1024 byte RAM block )
The same 1024 byte RAM block can be addressed on 1k boundaries throughout the 64k External Data Memory space.
RAM - 1024 Bytes
(accessable using MOVX command)
8.2.5.
Stack
A programmer's stack can be located anywhere in the 256-byte data memory. The stack area is designated using the Stack Pointer (SP, 0x81) SFR. The SP will point to the last location used. The next value pushed on the stack is placed at SP+1 and then SP is incremented. A reset initializes the stack pointer to location 0x07. Therefore, the first value pushed on the stack is placed at location 0x08, which is also the first register (R0) of register bank 1. Thus, if more than one register bank is to be used, the SP should be initialized to a location in the data memory not being used for data storage. The stack depth can extend up to 256 bytes. The MCUs also have built-in hardware for a stack record. The stack record is a 32-bit shift register, where each Push or increment SP pushes one record bit onto the register, and each Call or interrupt pushes two record bits onto the register. (A Pop or decrement SP pops one record bit, and a Return pops two record bits, also.) The stack record circuitry can also detect an overflow or underflow on the Stack, and can notify the debug software even with the MCU running full-speed debug.
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8.3. SPECIAL FUNCTION REGISTERS
C8051F018 C8051F019
The direct-access data memory locations from 0x80 to 0xFF constitute the special function registers (SFRs). The SFRs provide control and data exchange with the CIP-51's resources and peripherals. The CIP-51 duplicates the SFRs found in a typical 8051 implementation as well as implementing additional SFRs used to configure and access the sub-systems unique to the MCU. This allows the addition of new functionality while retaining compatibility with the MCS-51TM instruction set. Table 8.3 lists the SFRs implemented in the CIP-51 System Controller. The SFR registers are accessed any time the direct addressing mode is used to access memory locations from 0x80 to 0xFF. SFRs with addresses ending in 0x0 or 0x8 (e.g. P0, TCON, P1, SCON, IE, etc.) are bit-addressable as well as byte-addressable. All other SFRs are byte-addressable only. Unoccupied addresses in the SFR space are reserved for future use. Accessing these areas will have an indeterminate effect and should be avoided. Refer to the corresponding pages of the datasheet, as indicated in Table 8.3, for a detailed description of each register.
Table 8.2. Special Function Register Memory Map
F8 F0 E8 E0 D8 D0 C8 C0 B8 B0 A8 A0 98 90 88 80
SPI0CN B ADC0CN ACC PCA0CN PSW T2CON SMB0CN IP P3 IE P2 SCON P1 TCON P0 SBUF TMR3CN TMOD SP SPI0CFG TMR3RLL TL0 DPL SPI0DAT TMR3RLH TL1 DPH TMR3L TH0 PRT0CF OSCXCN SMB0STA PCA0L XBR0 PCA0MD REF0CN RCAP2L SMB0DAT AMX0CF OSCICN PRT1IF PRT1CF SPI0CKR TMR3H TH1 CKCON PSCTL PCON PRT2CF CPT0CN RCAP2H SMB0ADR AMX0SL TL2 ADC0GTL ADC0CF TH2 ADC0GTH ADC0LTL ADC0L FLSCL SMB0CR ADC0LTH ADC0H FLACL EMI0CN PRT3CF CPT1CN PCA0CPL0 XBR1 PCA0CPM0 PCA0CPL1 XBR2 PCA0CPM1 PCA0CPM2 PCA0CPM3 PCA0CPL2 PCA0CPL3 PCA0H PCA0CPH0 PCA0CPH1 PCA0CPH2 PCA0CPH3 PCA0CPH4 EIP1 PCA0CPL4 EIE1 PCA0CPM4 WDTCN EIP2 RSTSRC EIE2
0(8) Bit Addressable
1(9)
2(A)
3(B)
4(C)
5(D)
6(E)
7(F)
Table 8.3. Special Function Registers
SFRs are listed in alphabetical order. All undefined SFR locations are reserved. Address 0xE0 0xBC 0xE8 0xC5 0xC4 0xBF 0xBE 0xC7 0xC6 Register ACC ADC0CF ADC0CN ADC0GTH ADC0GTL ADC0H ADC0L ADC0LTH ADC0LTL Description Accumulator ADC Configuration ADC Control ADC Greater-Than Data Word (High Byte) ADC Greater-Than Data Word (Low Byte) ADC Data Word (High Byte) ADC Data Word (Low Byte) ADC Less-Than Data Word (High Byte) ADC Less-Than Data Word (Low Byte) Page No. 56 27 30 32 32 31 31 32 32
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Address 0xBA 0xBB 0xF0 0x8E 0x9E 0x9F 0x83 0x82 0xE6 0xE7 0xF6 0xF7 0xAF 0xB7 0xB6 0xA8 0xB8 0xB2 0xB1 0x80 0x90 0xA0 0xB0 0xD8 0xFA 0xFB 0xFC 0xFD 0xFE 0xEA 0xEB 0xEC 0xED 0xEE 0xDA 0xDB 0xDC 0xDD 0xDE 0xF9 0xE9 Register AMX0CF AMX0SL B CKCON CPT0CN CPT1CN DPH DPL EIE1 EIE2 EIP1 EIP2 EMI0CN FLACL FLSCL IE IP OSCICN OSCXCN P0 P1 P2 P3 PCA0CN PCA0CPH0 PCA0CPH1 PCA0CPH2 PCA0CPH3 PCA0CPH4 PCA0CPL0 PCA0CPL1 PCA0CPL2 PCA0CPL3 PCA0CPL4 PCA0CPM0 PCA0CPM1 PCA0CPM2 PCA0CPM3 PCA0CPM4 PCA0H PCA0L Description
PRELIMINARY
Page No. 27 28 56 123 37 39 54 54 61 62 63 64 72 70 71 59 60 80 81 89 90 91 92 139 142 142 142 142 142 142 142 142 142 142 141 141 141 141 141 142 142
ADC MUX Configuration ADC MUX Channel Selection B Register Clock Control Comparator 0 Control Comparator 1 Control Data Pointer (High Byte) Data Pointer (Low Byte) Extended Interrupt Enable 1 Extended Interrupt Enable 2 External Interrupt Priority 1 External Interrupt Priority 2 External Memory Interface Control Flash Access Limit Flash Memory Timing Prescaler Interrupt Enable Interrupt Priority Control Internal Oscillator Control External Oscillator Control Port 0 Latch Port 1 Latch Port 2 Latch Port 3 Latch Programmable Counter Array 0 Control PCA Capture Module 0 Data Word (High Byte) PCA Capture Module 1 Data Word (High Byte) PCA Capture Module 2 Data Word (High Byte) PCA Capture Module 3 Data Word (High Byte) PCA Capture Module 4 Data Word (High Byte) PCA Capture Module 0 Data Word (Low Byte) PCA Capture Module 1 Data Word (Low Byte) PCA Capture Module 2 Data Word (Low Byte) PCA Capture Module 3 Data Word (Low Byte) PCA Capture Module 4 Data Word (Low Byte) Programmable Counter Array 0 Capture/Compare 0 Programmable Counter Array 0 Capture/Compare 1 Programmable Counter Array 0 Capture/Compare 2 Programmable Counter Array 0 Capture/Compare 3 Programmable Counter Array 0 Capture/Compare 4 PCA Counter/Timer Data Word (High Byte) PCA Counter/Timer Data Word (Low Byte)
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Address 0xD9 0x87 0xA4 0xA5 0xAD 0xA6 0xA7 0x8F 0xD0 0xCB 0xCA 0xD1 0xEF 0x99 0x98 0xC3 0xC0 0xCF 0xC2 0xC1 0x81 0x9A 0x9D 0xF8 0x9B 0xC8 0x88 0x8C 0x8D 0xCD 0x8A 0x8B 0xCC 0x89 0x91 0x95 0x94 0x93 0x92 0xFF 0xE1 Register PCA0MD PCON PRT0CF PRT1CF PRT1IF PRT2CF PRT3CF PSCTL PSW RCAP2H RCAP2L REF0CN RSTSRC SBUF SCON SMB0ADR SMB0CN SMB0CR SMB0DAT SMB0STA SP SPI0CFG SPI0CKR SPI0CN SPI0DAT T2CON TCON TH0 TH1 TH2 TL0 TL1 TL2 TMOD TMR3CN TMR3H TMR3L TMR3RLH TMR3RLL WDTCN XBR0 Description Programmable Counter Array 0 Mode Power Control Port 0 Configuration Port 1 Configuration Port 1 Interrupt Flags Port 2 Configuration Port 3 Configuration Program Store RW Control Program Status Word Counter/Timer 2 Capture (High Byte) Counter/Timer 2 Capture (Low Byte) Voltage Reference Control Register Reset Source Register Serial Data Buffer (UART) Serial Port Control (UART) SMBus 0 Address SMBus 0 Control SMBus 0 Clock Rate SMBus 0 Data SMBus 0 Status Stack Pointer Serial Peripheral Interface Configuration SPI Clock Rate SPI Bus Control SPI Port 1Data Counter/Timer 2 Control Counter/Timer Control Counter/Timer 0 Data Word (High Byte) Counter/Timer 1 Data Word (High Byte) Counter/Timer 2 Data Word (High Byte) Counter/Timer 0 Data Word (Low Byte) Counter/Timer 1 Data Word (Low Byte) Counter/Timer 2 Data Word (Low Byte) Counter/Timer Mode Timer 3 Control Timer 3 High Timer 3 Low Timer 3 Reload High Timer 3 Reload Low Watchdog Timer Control Port I/O Crossbar Configuration 1
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Address Register Description
PRELIMINARY
Page No. 87 88
0xE2 XBR1 0xE3 XBR2 0x84-86, 0x96-97, 0x9C, 0xA1-A3, 0xA9-AC, 0xAE, 0xB3-B5, 0xB9, 0xBD, 0xC9, 0xCE, 0xDF, 0xE4-E5, 0xF1-F5
Port I/O Crossbar Configuration 2 Port I/O Crossbar Configuration 3
Reserved
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8.3.1. Register Descriptions
C8051F018 C8051F019
Following are descriptions of SFRs related to the operation of the CIP-51 System Controller. Reserved bits should not be set to logic l. Future product versions may use these bits to implement new features in which case the reset value of the bit will be logic 0, selecting the feature's default state. Detailed descriptions of the remaining SFRs are included in the sections of the datasheet associated with their corresponding system function.
Figure 8.3. SP: Stack Pointer
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000111
SFR Address:
0x81
Bits 7-0: SP: Stack Pointer. The stack pointer holds the location of the top of the stack. The stack pointer is incremented before every PUSH operation. The SP register defaults to 0x07 after reset.
Figure 8.4. DPL: Data Pointer Low Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0x82
Bits 7-0: DPL: Data Pointer Low. The DPL register is the low byte of the 16-bit DPTR. DPTR is used to access indirectly addressed RAM and Flash Memory.
Figure 8.5. DPH: Data Pointer High Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0x83
Bits 7-0: DPH: Data Pointer High. The DPH register is the high byte of the 16-bit DPTR. DPTR is used to access indirectly addressed RAM and Flash Memory.
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Figure 8.6. PSW: Program Status Word
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
CY
Bit7
AC
Bit6
F0
Bit5
RS1
Bit4
RS0
Bit3
OV
Bit2
F1
Bit1
PARITY
Bit0
(bit addressable)
00000000
SFR Address:
0xD0
Bit7:
CY: Carry Flag. This bit is set when the last arithmetic operation results in a carry (addition) or a borrow (subtraction). It is cleared to 0 by all other arithmetic operations. AC: Auxiliary Carry Flag. This bit is set when the last arithmetic operation results in a carry into (addition) or a borrow from (subtraction) the high order nibble. It is cleared to 0 by all other arithmetic operations. F0: User Flag 0. This is a bit-addressable, general purpose flag for use under software control.
Bit6:
Bit5:
Bits4-3: RS1-RS0: Register Bank Select. These bits select which register bank is used during register accesses. RS1 0 0 1 1 RS0 0 1 0 1 Register Bank 0 1 2 3 Address 0x00-0x07 0x08-0x0F 0x10-0x17 0x18-0x1F
Note: Any instruction which changes the RS1-RS0 bits must not be immediately followed by the "MOV Rn, A" instruction. Bit2: OV: Overflow Flag. This bit is set to 1 if the last arithmetic operation resulted in a carry (addition), borrow (subtraction), or overflow (multiply or divide). It is cleared to 0 by all other arithmetic operations. F1: User Flag 1. This is a bit-addressable, general purpose flag for use under software control. PARITY: Parity Flag. (Read only) This bit is set to 1 if the sum of the eight bits in the accumulator is odd and cleared if the sum is even.
Bit1: Bit0:
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Figure 8.7. ACC: Accumulator
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
ACC.7
Bit7
ACC.6
Bit6
ACC.5
Bit5
ACC.4
Bit4
ACC.3
Bit3
ACC.2
Bit2
ACC.1
Bit1
ACC.0
Bit0
(bit addressable)
00000000
SFR Address:
0xE0
Bits 7-0: ACC: Accumulator This register is the accumulator for arithmetic operations.
Figure 8.8. B: B Register
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
B.7
Bit7
B.6
Bit6
B.5
Bit5
B.4
Bit4
B.3
Bit3
B.2
Bit2
B.1
Bit1
B.0
Bit0
(bit addressable)
00000000
SFR Address:
0xF0
Bits 7-0: B: B Register This register serves as a second accumulator for certain arithmetic operations.
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8.4. INTERRUPT HANDLER
PRELIMINARY
The CIP-51 includes an extended interrupt system supporting a total of 22 interrupt sources with two priority levels. The allocation of interrupt sources between on-chip peripherals and external inputs pins varies according to the specific version of the device. Each interrupt source has one or more associated interrupt-pending flag(s) located in an SFR. When a peripheral or external source meets a valid interrupt condition, the associated interrupt-pending flag is set to logic 1. If interrupts are enabled for the source, an interrupt request is generated when the interrupt-pending flag is set. As soon as execution of the current instruction is complete, the CPU generates an LCALL to a predetermined address to begin execution of an interrupt service routine (ISR). Each ISR must end with an RETI instruction, which returns program execution to the next instruction that would have been executed if the interrupt request had not occurred. If interrupts are not enabled, the interrupt-pending flag is ignored by the hardware and program execution continues as normal. (The interrupt-pending flag is set to logic 1 regardless of the interrupt's enable/disable state.) Each interrupt source can be individually enabled or disabled through the use of an associated interrupt enable bit in an SFR (IE-EIE2). However, interrupts must first be globally enabled by setting the EA bit (IE.7) to logic 1 before the individual interrupt enables are recognized. Setting the EA bit to logic 0 disables all interrupt sources regardless of the individual interrupt-enable settings. Some interrupt-pending flags are automatically cleared by the hardware when the CPU vectors to the ISR. However, most are not cleared by the hardware and must be cleared by software before returning from the ISR. If an interruptpending flag remains set after the CPU completes the return-from-interrupt (RETI) instruction, a new interrupt request will be generated immediately and the CPU will re-enter the ISR after the completion of the next instruction.
8.4.1.
MCU Interrupt Sources and Vectors
The MCUs allocate 12 interrupt sources to on-chip peripherals. Up to 10 additional external interrupt sources are available depending on the I/O pin configuration of the device. Software can simulate an interrupt by setting any interrupt-pending flag to logic 1. If interrupts are enabled for the flag, an interrupt request will be generated and the CPU will vector to the ISR address associated with the interrupt-pending flag. MCU interrupt sources, associated vector addresses, priority order and control bits are summarized in Table 8.4. Refer to the datasheet section associated with a particular on-chip peripheral for information regarding valid interrupt conditions for the peripheral and the behavior of its interrupt-pending flag(s).
8.4.2.
External Interrupts
Two of the external interrupt sources (/INT0 and /INT1) are configurable as active-low level-sensitive or active-low edge-sensitive inputs depending on the setting of IT0 (TCON.0) and IT1 (TCON.2). IE0 (TCON.1) and IE1 (TCON.3) serve as the interrupt-pending flag for the /INT0 and /INT1 external interrupts, respectively. If an /INT0 or /INT1 external interrupt is configured as edge-sensitive, the corresponding interrupt-pending flag is automatically cleared by the hardware when the CPU vectors to the ISR. When configured as level sensitive, the interrupt-pending flag follows the state of the external interrupt's input pin. The external interrupt source must hold the input active until the interrupt request is recognized. It must then deactivate the interrupt request before execution of the ISR completes or another interrupt request will be generated. The remaining four external interrupts (External Interrupts 4-7) are active-low, edge-sensitive inputs. The interruptpending flags for these interrupts are in the Port 1 Interrupt Flag Register shown in Figure 13.10.
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Table 8.4. Interrupt Summary
Interrupt Source Reset External Interrupt 0 (/INT0) Timer 0 Overflow External Interrupt 1 (/INT1) Timer 1 Overflow Serial Port (UART) Timer 2 Overflow (or EXF2) Serial Peripheral Interface SMBus Interface ADC0 Window Comparison Programmable Counter Array 0 Comparator 0 Falling Edge Comparator 0 Rising Edge Comparator 1 Falling Edge Comparator 1 Rising Edge Timer 3 Overflow ADC0 End of Conversion External Interrupt 4 External Interrupt 5 External Interrupt 6 External Interrupt 7 Unused Interrupt Location External Crystal OSC Ready Interrupt Vector 0x0000 0x0003 0x000B 0x0013 0x001B 0x0023 0x002B 0x0033 0x003B 0x0043 0x004B 0x0053 0x005B 0x0063 0x006B 0x0073 0x007B 0x0083 0x008B 0x0093 0x009B 0x00A3 0x00AB Priority Order Top 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Interrupt-Pending Flag None IE0 (TCON.1) TF0 (TCON.5) IE1 (TCON.3) TF1 (TCON.7) RI (SCON.0) TI (SCON.1) TF2 (T2CON.7) SPIF (SPI0CN.7) SI (SMB0CN.3) ADWINT (ADC0CN.2) CF (PCA0CN.7) CCFn (PCA0CN.n) CP0FIF (CPT0CN.4) CP0RIF (CPT0CN.5) CP1FIF (CPT1CN.4) CP1RIF (CPT1CN.5) TF3 (TMR3CN.7) ADCINT (ADC0CN.5) IE4 (PRT1IF.4) IE5 (PRT1IF.5) IE6 (PRT1IF.6) IE7 (PRT1IF.7) None XTLVLD (OSCXCN.7)
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Enable Always enabled EX0 (IE.0) ET0 (IE.1) EX1 (IE.2) ET1 (IE.3) ES (IE.4) ET2 (IE.5) ESPI0 (EIE1.0) ESMB0 (EIE1.1) EWADC0 (EIE1.2) EPCA0 (EIE1.3) ECP0F (EIE1.4) ECP0R (EIE1.5) ECP1F (EIE1.6) ECP1R (EIE1.7) ET3 (EIE2.0) EADC0 (EIE2.1) EX4 (EIE2.2) EX5 (EIE2.3) EX6 (EIE2.4) EX7 (EIE2.5) Reserved (EIE2.6) EXVLD (EIE2.7)
8.4.3.
Interrupt Priorities
Each interrupt source can be individually programmed to one of two priority levels: low or high. A low priority interrupt service routine can be preempted by a high priority interrupt. A high priority interrupt cannot be preempted. Each interrupt has an associated interrupt priority bit in an SFR (IP-EIP2) used to configure its priority level. Low priority is the default. If two interrupts are recognized simultaneously, the interrupt with the higher priority is serviced first. If both interrupts have the same priority level, a fixed priority order is used to arbitrate.
8.4.4.
Interrupt Latency
Interrupt response time depends on the state of the CPU when the interrupt occurs. Pending interrupts are sampled and priority decoded each system clock cycle. Therefore, the fastest possible response time is 5 system clock cycles: 1 clock cycle to detect the interrupt and 4 clock cycles to complete the LCALL to the ISR. If an interrupt is pending when a RETI is executed, a single instruction is executed before an LCALL is made to service the pending interrupt. Therefore, the maximum response time for an interrupt (when no other interrupt is currently being serviced or the new interrupt is of greater priority) occurs when the CPU is performing an RETI instruction followed by a DIV as the next instruction. In this case, the response time is 18 system clock cycles: 1 clock cycle to detect the interrupt, 5 clock cycles to execute the RETI, 8 clock cycles to complete the DIV instruction and 4 clock cycles to execute the LCALL to the ISR. If the CPU is executing an ISR for an interrupt with equal or higher priority, the new interrupt will not be serviced until the current ISR completes, including the RETI and following instruction.
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8.4.5. Interrupt Register Descriptions
PRELIMINARY
The SFRs used to enable the interrupt sources and set their priority level are described below. Refer to the datasheet section associated with a particular on-chip peripheral for information regarding valid interrupt conditions for the peripheral and the behavior of its interrupt-pending flag(s).
Figure 8.9. IE: Interrupt Enable
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
EA
Bit7
IEGF0
Bit6
ET2
Bit5
ES
Bit4
ET1
Bit3
EX1
Bit2
ET0
Bit1
EX0
Bit0
(bit addressable)
00000000
SFR Address:
0xA8
Bit7:
EA: Enable All Interrupts. This bit globally enables/disables all interrupts. It overrides the individual interrupt mask settings. 0: Disable all interrupt sources. 1: Enable each interrupt according to its individual mask setting. IEGF0: General Purpose Flag 0. This is a general purpose flag for use under software control. ET2: Enable Timer 2 Interrupt. This bit sets the masking of the Timer 2 interrupt. 0: Disable all Timer 2 interrupts. 1: Enable interrupt requests generated by the TF2 flag (T2CON.7) ES: Enable Serial Port (UART) Interrupt. This bit sets the masking of the Serial Port (UART) interrupt. 0: Disable all UART interrupts. 1: Enable interrupt requests generated by the R1 flag (SCON.0) or T1 flag (SCON.1). ET1: Enable Timer 1 Interrupt. This bit sets the masking of the Timer 1 interrupt. 0: Disable all Timer 1 interrupts. 1: Enable interrupt requests generated by the TF1 flag (TCON.7). EX1: Enable External Interrupt 1. This bit sets the masking of external interrupt 1. 0: Disable external interrupt 1. 1: Enable interrupt requests generated by the /INT1 pin. ET0: Enable Timer 0 Interrupt. This bit sets the masking of the Timer 0 interrupt. 0: Disable all Timer 0 interrupts. 1: Enable interrupt requests generated by the TF0 flag (TCON.5). EX0: Enable External Interrupt 0. This bit sets the masking of external interrupt 0. 0: Disable external interrupt 0. 1: Enable interrupt requests generated by the /INT0 pin.
Bit6: Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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Figure 8.10. IP: Interrupt Priority
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
Bit7
Bit6
PT2
Bit5
PS
Bit4
PT1
Bit3
PX1
Bit2
PT0
Bit1
PX0
Bit0
(bit addressable)
00000000
SFR Address:
0xB8
Bits7-6: UNUSED. Read = 11b, Write = don't care. Bit5: PT2 Timer 2 Interrupt Priority Control. This bit sets the priority of the Timer 2 interrupts. 0: Timer 2 interrupt priority determined by default priority order. 1: Timer 2 interrupts set to high priority level. PS: Serial Port (UART) Interrupt Priority Control. This bit sets the priority of the Serial Port (UART) interrupts. 0: UART interrupt priority determined by default priority order. 1: UART interrupts set to high priority level. PT1: Timer 1 Interrupt Priority Control. This bit sets the priority of the Timer 1 interrupts. 0: Timer 1 interrupt priority determined by default priority order. 1: Timer 1 interrupts set to high priority level. PX1: External Interrupt 1 Priority Control. This bit sets the priority of the External Interrupt 1 interrupts. 0: External Interrupt 1 priority determined by default priority order. 1: External Interrupt 1 set to high priority level. PT0: Timer 0 Interrupt Priority Control. This bit sets the priority of the Timer 0 interrupts. 0: Timer 0 interrupt priority determined by default priority order. 1: Timer 0 interrupt set to high priority level. PX0: External Interrupt 0 Priority Control. This bit sets the priority of the External Interrupt 0 interrupts. 0: External Interrupt 0 priority determined by default priority order. 1: External Interrupt 0 set to high priority level.
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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Figure 8.11. EIE1: Extended Interrupt Enable 1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
ECP1R
Bit7
ECP1F
Bit6
ECP0R
Bit5
ECP0F
Bit4
EPCA0
Bit3
EWADC0
Bit2
ESMB0
Bit1
ESPI0
Bit0
00000000
SFR Address:
0xE6
Bit7:
ECP1R: Enable Comparator 1 (CP1) Rising Edge Interrupt. This bit sets the masking of the CP1 interrupt. 0: Disable CP1 Rising Edge interrupt. 1: Enable interrupt requests generated by the CP1RIF flag (CPT1CN.5). ECP1F: Enable Comparator 1 (CP1) Falling Edge Interrupt. This bit sets the masking of the CP1 interrupt. 0: Disable CP1 Falling Edge interrupt. 1: Enable interrupt requests generated by the CP1FIF flag (CPT1CN.4). ECP0R: Enable Comparator 0 (CP0) Rising Edge Interrupt. This bit sets the masking of the CP0 interrupt. 0: Disable CP0 Rising Edge interrupt. 1: Enable interrupt requests generated by the CP0RIF flag (CPT0CN.5). ECP0F: Enable Comparator 0 (CP0) Falling Edge Interrupt. This bit sets the masking of the CP0 interrupt. 0: Disable CP0 Falling Edge interrupt. 1: Enable interrupt requests generated by the CP0FIF flag (CPT0CN.4). EPCA0: Enable Programmable Counter Array (PCA0) Interrupt. This bit sets the masking of the PCA0 interrupts. 0: Disable all PCA0 interrupts. 1: Enable interrupt requests generated by PCA0. EWADC0: Enable Window Comparison ADC0 Interrupt. This bit sets the masking of ADC0 Window Comparison interrupt. 0: Disable ADC0 Window Comparison Interrupt. 1: Enable Interrupt requests generated by ADC0 Window Comparisons. ESMB0: Enable SMBus 0 Interrupt. This bit sets the masking of the SMBus interrupt. 0: Disable all SMBus interrupts. 1: Enable interrupt requests generated by the SI flag (SMB0CN.3). ESPI0: Enable Serial Peripheral Interface 0 Interrupt. This bit sets the masking of SPI0 interrupt. 0: Disable all SPI0 interrupts. 1: Enable Interrupt requests generated by the SPIF flag (SPI0CN.7).
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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Figure 8.12. EIE2: Extended Interrupt Enable 2
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
EXVLD
Bit7
Bit6
EX7
Bit5
EX6
Bit4
EX5
Bit3
EX4
Bit2
EADC0
Bit1
ET3
Bit0
00000000
SFR Address:
0xE7
Bit7:
EXVLD: Enable External Clock Source Valid (XTLVLD) Interrupt. This bit sets the masking of the XTLVLD interrupt. 0: Disable all XTLVLD interrupts. 1: Enable interrupt requests generated by the XTLVLD flag (OSCXCN.7) Reserved. Must Write 0. Reads 0. EX7: Enable External Interrupt 7. This bit sets the masking of External Interrupt 7. 0: Disable External Interrupt 7. 1: Enable interrupt requests generated by the External Interrupt 7 input pin. EX6: Enable External Interrupt 6. This bit sets the masking of External Interrupt 6. 0: Disable External Interrupt 6. 1: Enable interrupt requests generated by the External Interrupt 6 input pin. EX5: Enable External Interrupt 5. This bit sets the masking of External Interrupt 5. 0: Disable External Interrupt 5. 1: Enable interrupt requests generated by the External Interrupt 5 input pin. EX4: Enable External Interrupt 4. This bit sets the masking of External Interrupt 4. 0: Disable External Interrupt 4. 1: Enable interrupt requests generated by the External Interrupt 4 input pin. EADC0: Enable ADC0 End of Conversion Interrupt. This bit sets the masking of the ADC0 End of Conversion Interrupt. 0: Disable ADC0 Conversion Interrupt. 1: Enable interrupt requests generated by the ADC0 Conversion Interrupt. ET3: Enable Timer 3 Interrupt. This bit sets the masking of the Timer 3 interrupt. 0: Disable all Timer 3 interrupts. 1: Enable interrupt requests generated by the TF3 flag (TMR3CN.7)
Bit6: Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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Figure 8.13. EIP1: Extended Interrupt Priority 1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
PCP1R
Bit7
PCP1F
Bit6
PCP0R
Bit5
PCP0F
Bit4
PPCA0
Bit3
PWADC0
Bit2
PSMB0
Bit1
PSPI0
Bit0
00000000
SFR Address:
0xF6
Bit7:
PCP1R: Comparator 1 (CP1) Rising Interrupt Priority Control. This bit sets the priority of the CP1 interrupt. 0: CP1 rising interrupt set to low priority level. 1: CP1 rising interrupt set to high priority level. PCP1F: Comparator 1 (CP1) Falling Interrupt Priority Control. This bit sets the priority of the CP1 interrupt. 0: CP1 falling interrupt set to low priority level. 1: CP1 falling interrupt set to high priority level. PCP0R: Comparator 0 (CP0) Rising Interrupt Priority Control. This bit sets the priority of the CP0 interrupt. 0: CP0 rising interrupt set to low priority level. 1: CP0 rising interrupt set to high priority level. PCP0F: Comparator 0 (CP0) Falling Interrupt Priority Control. This bit sets the priority of the CP0 interrupt. 0: CP0 falling interrupt set to low priority level. 1: CP0 falling interrupt set to high priority level. PPCA0: Programmable Counter Array (PCA0) Interrupt Priority Control. This bit sets the priority of the PCA0 interrupt. 0: PCA0 interrupt set to low priority level. 1: PCA0 interrupt set to high priority level. PWADC0: ADC0 Window Comparator Interrupt Priority Control. This bit sets the priority of the ADC0 Window interrupt. 0: ADC0 Window interrupt set to low priority level. 1: ADC0 Window interrupt set to high priority level. PSMB0: SMBus 0 Interrupt Priority Control. This bit sets the priority of the SMBus interrupt. 0: SMBus interrupt set to low priority level. 1: SMBus interrupt set to high priority level. PSPI0: Serial Peripheral Interface 0 Interrupt Priority Control. This bit sets the priority of the SPI0 interrupt. 0: SPI0 interrupt set to low priority level. 1: SPI0 interrupt set to high priority level.
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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Figure 8.14. EIP2: Extended Interrupt Priority 2
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
PXVLD
Bit7
Bit6
PX7
Bit5
PX6
Bit4
PX5
Bit3
PX4
Bit2
PADC0
Bit1
PT3
Bit0
00000000
SFR Address:
0xF7
Bit7:
PXVLD: External Clock Source Valid (XTLVLD) Interrupt Priority Control. This bit sets the priority of the XTLVLD interrupt. 0: XTLVLD interrupt set to low priority level. 1: XTLVLD interrupt set to high priority level. Reserved: Must write 0. Reads 0. PX7: External Interrupt 7 Priority Control. This bit sets the priority of the External Interrupt 7. 0: External Interrupt 7 set to low priority level. 1: External Interrupt 7 set to high priority level. PX6: External Interrupt 6 Priority Control. This bit sets the priority of the External Interrupt 6. 0: External Interrupt 6 set to low priority level. 1: External Interrupt 6 set to high priority level. PX5: External Interrupt 5 Priority Control. This bit sets the priority of the External Interrupt 5. 0: External Interrupt 5 set to low priority level. 1: External Interrupt 5 set to high priority level. PX4: External Interrupt 4 Priority Control. This bit sets the priority of the External Interrupt 4. 0: External Interrupt 4 set to low priority level. 1: External Interrupt 4 set to high priority level. PADC0: ADC End of Conversion Interrupt Priority Control. This bit sets the priority of the ADC0 End of Conversion Interrupt. 0: ADC0 End of Conversion interrupt set to low priority level. 1: ADC0 End of Conversion interrupt set to high priority level. PT3: Timer 3 Interrupt Priority Control. This bit sets the priority of the Timer 3 interrupts. 0: Timer 3 interrupt priority determined by default priority order. 1: Timer 3 interrupt set to high priority level.
Bit6: Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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8.5. Power Management Modes
PRELIMINARY
The CIP-51 core has two software programmable power management modes: Idle and Stop. Idle mode halts the CPU while leaving the external peripherals and internal clocks active. In Stop mode, the CPU is halted, all interrupts and timers (except the Missing Clock Detector) are inactive, and the system clock is stopped. Since clocks are running in Idle mode, power consumption is dependent upon the system clock frequency and the number of peripherals left in active mode before entering Idle. Stop mode consumes the least power. Figure 8.15 describes the Power Control Register (PCON) used to control the CIP-51's power management modes. Although the CIP-51 has Idle and Stop modes built in (as with any standard 8051 architecture), power management of the entire MCU is better accomplished by enabling/disabling individual peripherals as needed. Each analog peripheral can be disabled when not in use and put into low power mode. Digital peripherals, such as timers or serial buses, draw little power whenever they are not in use. Turning off the oscillator saves even more power, but requires a reset to restart the MCU.
8.5.1.
Idle Mode
Setting the Idle Mode Select bit (PCON.0) causes the CIP-51 to halt the CPU and enter Idle mode as soon as the instruction that sets the bit completes. All internal registers and memory maintain their original data. All analog and digital peripherals can remain active during Idle mode. Idle mode is terminated when an enabled interrupt or /RST is asserted. The assertion of an enabled interrupt will cause the Idle Mode Selection bit (PCON.0) to be cleared and the CPU will resume operation. The pending interrupt will be serviced and the next instruction to be executed after the return from interrupt (RETI) will be the instruction immediately following the one that set the Idle Mode Select bit. If Idle mode is terminated by an internal or external reset, the CIP-51 performs a normal reset sequence and begins program execution at address 0x0000. If enabled, the WDT will eventually cause an internal watchdog reset and thereby terminate the Idle mode. This feature protects the system from an unintended permanent shutdown in the event of an inadvertent write to the PCON register. If this behavior is not desired, the WDT may be disabled by software prior to entering the Idle mode if the WDT was initially configured to allow this operation. This provides the opportunity for additional power savings, allowing the system to remain in the Idle mode indefinitely, waiting for an external stimulus to wake up the system. Refer to Section 11.8 Watchdog Timer for more information on the use and configuration of the WDT.
8.5.2.
Stop Mode
Setting the Stop Mode Select bit (PCON.1) causes the CIP-51 to enter Stop mode as soon as the instruction that sets the bit completes. In Stop mode, the CPU and oscillators are stopped, effectively shutting down all digital peripherals. Each analog peripheral must be shut down individually prior to entering Stop Mode. Stop mode can only be terminated by an internal or external reset. On reset, the CIP-51 performs the normal reset sequence and begins program execution at address 0x0000. If enabled, the Missing Clock Detector will cause an internal reset and thereby terminate the Stop mode. The Missing Clock Detector should be disabled if the CPU is to be put to sleep for longer than the MCD timeout of 100sec.
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Figure 8.15. PCON: Power Control Register
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
SMOD
Bit7
GF4
Bit6
GF3
Bit5
GF2
Bit4
GF1
Bit3
GF0
Bit2
STOP
Bit1
IDLE
Bit0
00000000
SFR Address:
0x87
Bit7:
SMOD: Serial Port Baud Rate Doubler Enable. 0: Serial Port baud rate is that defined by Serial Port Mode in SCON. 1: Serial Port baud rate is double that defined by Serial Port Mode in SCON.
Bits6-2: GF4-GF0: General Purpose Flags 4-0. These are general purpose flags for use under software control. Bit1: STOP: Stop Mode Select. Setting this bit will place the CIP-51 in Stop mode. This bit will always be read as 0. 1: Goes into power down mode. (Turns off oscillator). IDLE: Idle Mode Select. Setting this bit will place the CIP-51 in Idle mode. This bit will always be read as 0. 1: Goes into idle mode. (Shuts off clock to CPU, but clock to Timers, Interrupts, Serial Ports, and Analog Peripherals are still active.)
Bit0:
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9. FLASH MEMORY
PRELIMINARY
These devices include 16k + 128 bytes of on-chip, reprogrammable Flash memory for program code and non-volatile data storage. The Flash memory can be programmed in-system, a single byte at a time, through the JTAG interface or by software using the MOVX instruction. Once cleared to 0, a Flash bit must be erased to set it back to 1. The bytes would typically be erased (set to 0xFF) before being reprogrammed. The write and erase operations are automatically timed by hardware for proper execution. Data polling to determine the end of the write/erase operation is not required. Refer to Table 9.1 for the electrical characteristics of the Flash memory.
9.1.
Programming The Flash Memory
The simplest means of programming the Flash memory is through the JTAG interface using programming tools provided by Cygnal or a third party vendor. This is the only means for programming a non-initialized device. For details on the JTAG commands to program Flash memory, see Section 19.2. The Flash memory can be programmed by software using the MOVX instruction with the address and data byte to be programmed provided as normal operands. Before writing to Flash memory using MOVX, Flash write operations must be enabled by setting the PSWE Program Store Write Enable bit (PSCTL.0) to logic 1. Writing to Flash remains enabled until the PSWE bit is cleared by software. Writes to Flash memory can clear bits but cannot set them. Only an erase operation can set bits in Flash. Therefore, the byte location to be programmed must be erased before a new value can be written. The 16kbyte Flash memory is organized in 512-byte sectors. The erase operation applies to an entire sector (setting all bytes in the sector to 0xFF). Setting the PSEE Program Store Erase Enable bit (PSCTL.1) and PSWE (PSCTL.0) bit to logic 1 and then using the MOVX command to write a data byte to any byte location within the sector will erase an entire 512-byte sector. The data byte written can be of any value because it is not actually written to the Flash. Flash erasure remains enabled until the PSEE bit is cleared by software. The following sequence illustrates the algorithm for programming the Flash memory by software: 1. 2. 3. 4. 5. 6. 7. Enable Flash Memory write/erase in FLSCL Register using FLASCL bits. Set PSEE (PSCTL.1) to enable Flash sector erase. Set PSWE (PSCTL.0) to enable Flash writes. Use MOVX to write a data byte to any location within the 512-byte sector to be erased. Clear PSEE to disable Flash sector erase. Use MOVX to write a data byte to the desired byte location within the erased 512-byte sector. Repeat until finished. (Any number of bytes can be written from a single byte to and entire sector.) Clear the PSWE bit to disable Flash writes.
Write/Erase timing is automatically controlled by hardware based on the prescaler value held in the Flash Memory Timing Prescaler register (FLSCL). The 4-bit prescaler value FLASCL determines the time interval for write/erase operations. The FLASCL value required for a given system clock is shown in Figure 9.4, along with the formula used to derive the FLASCL values. When FLASCL is set to 1111b, the write/erase operations are disabled. Note that code execution in the 8051 is stalled while the Flash is being programmed or erased.
Table 9.1. FLASH Memory Electrical Characteristics
VDD = 2.8 to 3.6V, -40 C to +85 C unless otherwise specified. PARAMETER CONDITIONS Endurance Erase Cycle Time Write Cycle Time MIN 20k 10 40 TYP 100k MAX UNITS Erase/Wr ms s
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9.2. Non-volatile Data Storage
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The Flash memory can be used for non-volatile data storage as well as program code. This allows data such as calibration coefficients to be calculated and stored at run time. Data is written using the MOVX instruction and read using the MOVC instruction.
9.3.
Security Options
The CIP-51 provides security options to protect the Flash memory from inadvertent modification by software as well as prevent the viewing of proprietary program code and constants. The Program Store Write Enable (PSCTL.0) and the Program Store Erase Enable (PSCTL.1) bits protect the Flash memory from accidental modification by software. These bits must be explicitly set to logic 1 before software can modify the Flash memory. Additional security features prevent proprietary program code and data constants from being read or altered across the JTAG interface or by software running on the system controller. A set of security lock bytes stored at 0x3DFE and 0x3DFF protect the Flash program memory from being read or altered across the JTAG interface. Each bit in a security lock-byte protects one 4kbyte block of memory. Clearing a bit to logic 0 in a Read lock byte prevents the corresponding block of Flash memory from being read across the JTAG interface. Clearing a bit in the Write/Erase lock byte protects the block from JTAG erasures and/or writes. The Read lock byte is at location 0x3DFF. The Write/Erase lock byte is located at 0x3DFE. Figure 9.2 shows the location and bit definitions of the security bytes. The 512-byte sector containing the lock bytes can be written to, but not erased by software.
Figure 9.1. PSCTL: Program Store RW Control
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
PSEE
Bit1
PSWE
Bit0
00000000
SFR Address:
0x8F
Bits7-2: UNUSED. Read = 000000b, Write = don't care. Bit1: PSEE: Program Store Erase Enable. Setting this bit allows an entire page of the Flash program memory to be erased provided the PSWE bit is also set. After setting this bit, a write to Flash memory using the MOVX instruction will erase the entire page that contains the location addressed by the MOVX instruction. The value of the data byte written does not matter. 0: Flash program memory erasure disabled. 1: Flash program memory erasure enabled. PSWE: Program Store Write Enable. Setting this bit allows writing a byte of data to the Flash program memory using the MOVX instruction. The location must be erased before writing data. 0: Write to Flash program memory disabled. 1: Write to Flash program memory enabled.
Bit0:
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Figure 9.2. Flash Program Memory Security Bytes
0x807F 0x8000 0x7FFF
Reserved
0x3E00
Read Lock Byte Write/Erase Lock Byte Program Memory Space
0x3DFF 0x3DFE 0x3DFD
Read and Write/Erase Security Bits. (Bit 7 is MSB.) Note: Bits 7-0 must all be set to lock the block at 0x8000-0x807F
Bit
Software Read Limit
Memory Block
0x0000
7 6 5 4 3 2 1 0
0x3000 - 0x3FFF 0x2000 - 0x2FFF 0x1000 - 0x1FFF 0x0000 - 0x0FFF
FLASH Read Lock Byte Bits7-0: Each bit locks a corresponding block of memory. (Bit 7 is MSB.) 0: Read operations are locked (disabled) for corresponding block across the JTAG interface. 1: Read operations are unlocked (enabled) for corresponding block across the JTAG interface. FLASH Write/Erase Lock Byte Bits7-0: Each bit locks a corresponding block of memory. 0: Write/Erase operations are locked (disabled) for corresponding block across the JTAG interface. 1: Write/Erase operations are unlocked (enabled) for corresponding block across the JTAG interface. FLASH Access Limit Register (FLACL) The content of this register is used as the high byte of the 16-bit software read limit address. The 16bit read limit address value is calculated as 0xNN00 where NN is replaced by the contents of this register. Software running at or above this address is prohibited from using the MOVX or MOVC instructions to read, write, or erase, locations below this address. Any attempts to read locations below this limit will return the value 0x00.
The lock bits can always be read and cleared to logic 0 regardless of the security setting applied to the block containing the security bytes. This allows additional blocks to be protected after the block containing the security bytes has been locked. However, the only means of removing a lock once set is to erase the entire program memory space by performing a JTAG erase operation (i.e. cannot be done in user firmware). NOTE: Addressing either security byte while performing a JTAG erase operation will automatically initiate erasure of the entire program memory space (except for the reserved area). This erasure can only be performed via JTAG. If a non-security byte in the 0x3C00-0x3DFF page is addressed during erasure, only that page (including the security bytes) will be erased. The Flash Access Limit security feature (see Figure 9.3) protects proprietary program code and data from being read by software running on the C8051F018/9 MCUs. This feature provides support for OEMs that wish to program the MCU with proprietary value-added firmware before distribution. The value-added firmware can be protected while allowing additional code to be programmed in remaining program memory space later.
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The Software Read Limit (SRL) is a 16-bit address that establishes two logical partitions in the program memory space. The first is an upper partition consisting of all the program memory locations at or above the SRL address, and the second is a lower partition consisting of all the program memory locations starting at 0x0000 up to (but excluding) the SRL address. Software in the upper partition can execute code in the lower partition, but is prohibited from reading locations in the lower partition using the MOVC instruction. (Executing a MOVC instruction from the upper partition with a source address in the lower partition will always return a data value of 0x00.) Software running in the lower partition can access locations in both the upper and lower partition without restriction. The Value-added firmware should be placed in the lower partition. On reset, control is passed to the value-added firmware via the reset vector. Once the value-added firmware completes its initial execution, it branches to a predetermined location in the upper partition. If entry points are published, software running in the upper partition may execute program code in the lower partition, but it cannot read the contents of the lower partition. Parameters may be passed to the program code running in the lower partition either through the typical method of placing them on the stack or in registers before the call or by placing them in prescribed memory locations in the upper partition. The SRL address is specified using the contents of the Flash Access Register. The 16-bit SRL address is calculated as 0xNN00, where NN is the contents of the SRL Security Register. Thus, the SRL can be located on 256-byte boundaries anywhere in program memory space. However, the 512-byte erase sector size essentially requires that a 512 boundary be used. The contents of a non-initialized SRL security byte is 0x00, thereby setting the SRL address to 0x0000 and allowing read access to all locations in program memory space by default.
Figure 9.3. FLACL: Flash Access Limit
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xB7
Bits 7-0: FLACL: Flash Access Limit. This register holds the high byte of the 16-bit program memory read/write/erase limit address. The entire 16-bit access limit address value is calculated as 0xNN00 where NN is replaced by contents of FLACL. A write to this register sets the Flash Access Limit. This register can only be written once after any reset. Any subsequent writes are ignored until the next reset.
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Figure 9.4. FLSCL: Flash Memory Timing Prescaler
R/W R/W R/W R/W R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
FOSE
Bit7
FRAE
Bit6
Bit5
Bit4
FLASCL
10001111
SFR Address:
0xB6
FOSE: Flash One-Shot Timer Enable 0: Flash One-shot timer disabled. 1: Flash One-shot timer enabled Bit6: FRAE: Flash Read Always Enable 0: Flash reads per one-shot timer 1: Flash always in read mode Bits5-4: UNUSED. Read = 00b, Write = don't care. Bits3-0: FLASCL: Flash Memory Timing Prescaler. This register specifies the prescaler value for a given system clock required to generate the correct timing for Flash write/erase operations. If the prescaler is set to 1111b, Flash write/erase operations are disabled. 0000: System Clock < 50kHz 0001: 50kHz System Clock < 100kHz 0010: 100kHz System Clock < 200kHz 0011: 200kHz System Clock < 400kHz 0100: 400kHz System Clock < 800kHz 0101: 800kHz System Clock < 1.6MHz 0110: 1.6MHz System Clock < 3.2MHz 0111: 3.2MHz System Clock < 6.4MHz 1000: 6.4MHz System Clock < 12.8MHz 1001: 12.8MHz System Clock < 25.6MHz 1010: 25.6MHz System Clock < 51.2MHz * 1011, 1100, 1101, 1110: Reserved Values 1111: Flash Memory Write/Erase Disabled The prescaler value is the smallest value satisfying the following equation: FLASCL > log2(System Clock / 50kHz) * For test purposes. The C8051F018/9 is not guaranteed for operation over 25MHz.
Bit7:
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10. EXTERNAL RAM
C8051F018 C8051F019
The C8051F018/9 includes 1024 bytes of RAM mapped into the external data memory space. All of these address locations may be accessed using the external move instruction (MOVX) and the data pointer (DPTR), or using MOVX indirect addressing mode. If the MOVX instruction is used with an 8-bit address operand (such as @R1), then the high byte of the 16-bit address is provided by the External Memory Interface Control Register (EMI0CN as shown in Figure 10.1). Note: the MOVX instruction is also used for writes to the Flash memory. See Section 9 for details. The MOVX instruction accesses XRAM by default (i.e. PSTCL.0 = 0). For any of the addressing modes the upper 5-bits of the 16-bit external data memory address word are "don't cares". As a result, the 1024-byte RAM is mapped modulo style over the entire 64k external data memory address range. For example, the XRAM byte at address 0x0000 is also at address 0x0400, 0x0800, 0x0C00, 0x1000, etc. This is a useful feature when doing a linear memory fill, as the address pointer doesn't have to be reset when reaching the RAM block boundary.
Figure 10.1. EMI0CN: External Memory Interface Control
R R R R R R/W R/W R/W Reset Value
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
PGSEL1
Bit1
PGSEL0
Bit0
00000000
SFR Address:
0xAF
Bits 7-2: Not Used - reads 000000b Bits 1-0: PGSEL[1:0]: XRAM Page Select Bits The XRAM Page Select Bits provide the high byte of the 16-bit external data memory address when using an 8-bit MOVX command, effectively selecting a 256-byte page of RAM. The upper 6-bits are "don't cares", so the 1k address blocks are repeated modulo over the entire 64k external data memory address space. 00: xxxxxx00b 01: xxxxxx01b 10: xxxxxx10b 11: xxxxxx11b
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11. RESET SOURCES
PRELIMINARY
The reset circuitry of the MCUs allows the controller to be easily placed in a predefined default condition. On entry to this reset state, the CIP-51 halts program execution, forces the external port pins to a known state and initializes the SFRs to their defined reset values. Interrupts and timers are disabled. On exit, the program counter (PC) is reset, and program execution starts at location 0x0000. All of the SFRs are reset to predefined values. The reset values of the SFR bits are defined in the SFR detailed descriptions. The contents of internal data memory are not changed during a reset and any previously stored data is preserved. However, since the stack pointer SFR is reset, the stack is effectively lost even though the data on the stack are not altered. The I/O port latches are reset to 0xFF (all logic ones), activating internal weak pull-ups which take the external I/O pins to a high state. If the source of reset is from the VDD Monitor or writing a 1 to PORSF, the /RST pin is driven low until the end of the VDD reset timeout. On exit from the reset state, the MCU uses the internal oscillator running at 2MHz as the system clock by default. Refer to Section 12 for information on selecting and configuring the system clock source. The Watchdog Timer is enabled using its longest timeout interval. (Section 11.8 details the use of the Watchdog Timer.) There are seven sources for putting the MCU into the reset state: power-on/power-fail, external /RST pin, external CNVSTR signal, software commanded, Comparator 0, Missing Clock Detector, and Watchdog Timer. Each reset source is described below:
Figure 11.1. Reset Sources Diagram
VDD
(Port I/O)
Crossbar
CNVSTR
CNVRSEF
Supply Monitor
+ -
Comparator 0 CP0+ CP0+ C0RSEF
Supply Reset Timeout
(wired-OR)
/RST
System Clock
Missing Clock Detector (oneshot)
EN
Reset Funnel
WDT
MCD Enable
(Software Reset)
EN PRE
SWRSF
WDT Enable
WDT Strobe
CIP-51 Core
System Reset
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11.1. Power-on Reset
C8051F018 C8051F019
The C8051F018/9 incorporates a power supply monitor that holds the MCU in the reset state until VDD rises above the VRST level during power-up. (See Figure 11.2 for timing diagram, and refer to Table 11.1 for the Electrical Characteristics of the power supply monitor circuit.) The /RST pin is asserted (low) until the end of the 100ms VDD Monitor timeout in order to allow the VDD supply to become stable. On exit from a power-on reset, the PORSF flag (RSTSRC.1) is set by hardware to logic 1. All of the other reset flags in the RSTSRC Register are indeterminate. PORSF is cleared by a reset from any other source. Since all resets cause program execution to begin at the same location (0x0000), software can read the PORSF flag to determine if a power-up was the cause of reset. The content of internal data memory should be assumed to be undefined after a power-on reset.
11.2.
Software Forced Reset
Writing a 1 to the PORSF bit forces a Power-On Reset as described in Section 11.1.
Figure 11.2. VDD Monitor Timing Diagram
volts 2.80 2.40 2.0
VRST
1.0
VD D
t Logic HIGH
/RST
100ms 100ms
Logic LOW
11.3.
Power-fail Reset
When a power-down transition or power irregularity causes VDD to drop below VRST, the power supply monitor will drive the /RST pin low and return the CIP-51 to the reset state (see Figure 11.2). When VDD returns to a level above VRST, the CIP-51 will leave the reset state in the same manner as that for the power-on reset. Note that even though internal data memory contents are not altered by the power-fail reset, it is impossible to determine if VDD dropped below the level required for data retention. If the PORSF flag is set, the data may no longer be valid.
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11.4. External Reset
PRELIMINARY
The external /RST pin provides a means for external circuitry to force the MCU into a reset state. Asserting an active-low signal on the /RST pin will cause the MCU to enter the reset state. Although there is a weak internal pullup, it may be desirable to provide an external pull-up and/or decoupling of the /RST pin to avoid erroneous noise-induced resets. The MCU will remain in reset until at least 12 clock cycles after the active-low /RST signal is removed. The PINRSF flag (RSTSRC.0) is set on exit from an external reset. The /RST pin is also 5V tolerant.
11.5.
Missing Clock Detector Reset
The Missing Clock Detector is essentially a one-shot circuit that is triggered by the MCU system clock. If the system clock goes away for more than 100s, the one-shot will time out and generate a reset. After a Missing Clock Detector reset, the MCDRSF flag (RSTSRC.2) will be set, signifying the MSD as the reset source; otherwise, this bit reads 0. The state of the /RST pin is unaffected by this reset. Setting the MSCLKE bit in the OSCICN register (see Figure 12.2) enables the Missing Clock Detector.
11.6.
Comparator 0 Reset
Comparator 0 can be configured as an active-low reset input by writing a 1 to the C0RSEF flag (RSTSRC.5). Comparator 0 should be enabled using CPT0CN.7 (see Figure 6.3) at least 20s prior to writing to C0RSEF to prevent any turn-on chatter on the output from generating an unwanted reset. When configured as a reset, if the noninverting input voltage (on CP0+) is less than the inverting input voltage (on CP0-), the MCU is put into the reset state. After a Comparator 0 Reset, the C0RSEF flag (RSTSRC.5) will read 1 signifying Comparator 0 as the reset source; otherwise, this bit reads 0. The state of the /RST pin is unaffected by this reset. Also, Comparator 0 can generate a reset with or without the system clock.
11.7.
External CNVSTR Pin Reset
The external CNVSTR signal can be configured as an active-low reset input by writing a 1 to the CNVRSEF flag (RSTSRC.6). The CNVSTR signal can appear on any of the P0, P1, or P2 I/O pins as described in Section 13.1. (Note that the Crossbar must be configured for the CNVSTR signal to be routed to the appropriate Port I/O.) The Crossbar should be configured and enabled before the CNVRSEF is set to configure CNVSTR as a reset source. When configured as a reset, CNVSTR is active-low and level sensitive. After a CNVSTR reset, the CNVRSEF flag (RSTSRC.6) will read 1 signifying CNVSTR as the reset source; otherwise, this bit reads 0. The state of the /RST pin is unaffected by this reset.
11.8.
Watchdog Timer Reset
The MCU includes a programmable Watchdog Timer (WDT) running off the system clock. The WDT will force the MCU into the reset state when the watchdog timer overflows. To prevent the reset, the WDT must be restarted by application software before the overflow occurs. If the system experiences a software/hardware malfunction preventing the software from restarting the WDT, the WDT will overflow and cause a reset. This should prevent the system from running out of control. The WDT is automatically enabled and started with the default maximum time interval on exit from all resets. If desired the WDT can be disabled by system software or locked on to prevent accidental disabling. Once locked, the WDT cannot be disabled until the next system reset. The state of the /RST pin is unaffected by this reset.
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11.8.1. Watchdog Usage
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The WDT consists of a 21-bit timer running from the programmed system clock. The timer measures the period between specific writes to its control register. If this period exceeds the programmed limit, a WDT reset is generated. The WDT can be enabled and disabled as needed in software, or can be permanently enabled if desired. Watchdog features are controlled via the Watchdog Timer Control Register (WDTCN) shown in Figure 11.3. Enable/Reset WDT The watchdog timer is both enabled and the countdown restarted by writing 0xA5 to the WDTCN register. The user's application software should include periodic writes of 0xA5 to WDTCN as needed to prevent a watchdog timer overflow. The WDT is enabled and restarted as a result of any system reset. Disable WDT Writing 0xDE followed by 0xAD to the WDTCN register disables the WDT. The following code segment illustrates disabling the WDT. CLR EA ; disable all interrupts MOV WDTCN,#0DEh ; disable software MOV WDTCN,#0ADh ; watchdog timer SETB EA ; re-enable interrupts The writes of 0xDE and 0xAD must occur within 4 clock cycles of each other, or the disable operation is ignored. Interrupts should be disabled during this procedure to avoid delay between the two writes. Disable WDT Lockout Writing 0xFF to WDTCN locks out the disable feature. Once locked out, the disable operation is ignored until the next system reset. Writing 0xFF does not enable or reset the watchdog timer. Applications always intending to use the watchdog should write 0xFF to WDTCN in their initialization code. Setting WDT Interval WDTCN.[2:0] control the watchdog timeout interval. The interval is given by the following equation: 43+WDTCN[2:0] x TSYSCLK , (where TSYSCLK is the system clock period). For a 2MHz system clock, this provides an interval range of 0.032msec to 524msec. WDTCN.7 must be a 0 when setting this interval. Reading WDTCN returns the programmed interval. WDTCN.[2:0] is 111b after a system reset.
Figure 11.3. WDTCN: Watchdog Timer Control Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
xxxxx111
SFR Address:
0xFF
Bits7-0: WDT Control Writing 0xA5 both enables and reloads the WDT. Writing 0xDE followed within 4 clocks by 0xAD disables the WDT. Writing 0xFF locks out the disable feature. Bit4: Watchdog Status Bit (when Read) Reading the WDTCN.[4] bit indicates the Watchdog Timer Status. 0: WDT is inactive 1: WDT is active Bits2-0: Watchdog Timeout Interval Bits The WDTCN.[2:0] bits set the Watchdog Timeout Interval. When writing these bits, WDTCN.7 must be set to 0.
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Figure 11.4. RSTSRC: Reset Source Register
R
R/W
R/W
R/W
R
R
R/W
R
Reset Value
JTAGRST
Bit7
CNVRSEF
Bit6
C0RSEF
Bit5
SWRSEF
Bit4
WDTRSF
Bit3
MCDRSF
Bit2
PORSF
Bit1
PINRSF
Bit0
xxxxxxxx
SFR Address:
0xEF
(Note: Do not use read-modify-write operations on this register.) Bit7: Bit6: JTAGRST. JTAG Reset Flag. 0: JTAG is not currently in reset state. 1: JTAG is in reset state. CNVRSEF: Convert Start Reset Source Enable and Flag Write 0: CNVSTR is not a reset source 1: CNVSTR is a reset source (active low) Read 0: Source of prior reset was not from CNVSTR 1: Source of prior reset was from CNVSTR C0RSEF: Comparator 0 Reset Enable and Flag Write 0: Comparator 0 is not a reset source 1: Comparator 0 is a reset source (active low) Read 0: Source of prior reset was not from Comparator 0 1: Source of prior reset was from Comparator 0 SWRSF: Software Reset Force and Flag Write 0: No Effect 1: Forces an internal reset. /RST pin is not effected. Read 0: Prior reset source was not from write to the SWRSF bit. 1: Prior reset source was from write to the SWRSF bit. WDTRSF: Watchdog Timer Reset Flag 0: Source of prior reset was not from WDT timeout. 1: Source of prior reset was from WDT timeout. MCDRSF: Missing Clock Detector Flag 0: Source of prior reset was not from Missing Clock Detector timeout. 1: Source of prior reset was from Missing Clock Detector timeout. PORSF: Power-On Reset Force and Flag Write 0: No effect 1: Forces a Power-On Reset. /RST is driven low. Read 0: Source of prior reset was not from POR. 1: Source of prior reset was from POR. PINRSF: HW Pin Reset Flag 0: Source of prior reset was not from /RST pin. 1: Source of prior reset was from /RST pin.
Bit5:
Bit4:
Bit3: Bit2: Bit1:
Bit0:
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Table 11.1. Reset Electrical Characteristics
-40 C to +85 C unless otherwise specified. PARAMETER CONDITIONS /RST Output Low Voltage IOL = 8.5mA, VDD = 2.8 to 3.6V /RST Input High Voltage /RST Input Low Voltage /RST Input Leakage Current VDD for /RST Output Valid AV+ for /RST Output Valid VDD POR Threshold (VRST) Reset Time Delay Missing Clock Detector Timeout /RST = 0.0V 1.0 1.0 2.40 80 100 MIN 0.7 x VDD
C8051F018 C8051F019
TYP
MAX 0.6
UNITS V V V
A V V V ms s
0.3 x VDD 20
/RST rising edge after crossing reset threshold Time from last system clock to reset generation
2.55 100 220
2.80 120 500
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12. OSCILLATOR
PRELIMINARY
Each MCU includes an internal oscillator and an external oscillator drive circuit, either of which can generate the system clock. The MCUs boot from the internal oscillator after any reset. The internal oscillator starts up instantly. It can be enabled/disabled and its frequency can be changed using the Internal Oscillator Control Register (OSCICN) as shown in Figure 12.2. The internal oscillator's electrical specifications are given in Table 12.1. Both oscillators are disabled when the /RST pin is held low. The MCUs can run from the internal oscillator or external oscillator, and switch between the two at will using the CLKSL bit in the OSCICN Register. The external oscillator requires an external resonator, parallel-mode crystal, capacitor, or RC network connected to the XTAL1/XTAL2 pins (see Figure 12.1). The oscillator circuit must be configured for one of these sources in the OSCXCN register. An external CMOS clock can also provide the system clock via overdriving the XTAL1 pin. The XTAL1 and XTAL2 pins are 3.6V (not 5V) tolerant. The external oscillator can be left enabled and running even when the MCU has switched to using the internal oscillator.
Figure 12.1. Oscillator Diagram
OSCICN
MSCLKE IFRDY CLKSL IOSCEN IFCN1 IFCN0
EN
VDD
Internal Clock Generator SYSCLK opt. 1
XTAL1
opt. 2
AV+ AV+ XTAL1 XTAL2
Input Circuit OSC opt. 4
XTAL1
opt. 3
XTAL1
XTAL2
AGND
XTLVLD XOSCMD2 XOSCMD1 XOSCMD0 XFCN2 XFCN1 XFCN0
OSCXCN
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Figure 12.2. OSCICN: Internal Oscillator Control Register
R/W R/W R/W R R/W R/W R/W R/W Reset Value
MSCLKE
Bit7
Bit6
Bit5
IFRDY
Bit4
CLKSL
Bit3
IOSCEN
Bit2
IFCN1
Bit1
IFCN0
Bit0
00000100
SFR Address:
0xB2
Bit7:
MSCLKE: Missing Clock Enable Bit 0: Missing Clock Detector Disabled 1: Missing Clock Detector Enabled; triggers a reset if a missing clock is detected Bits6-5: UNUSED. Read = 00b, Write = don't care Bit4: IFRDY: Internal Oscillator Frequency Ready Flag 0: Internal Oscillator Frequency not running at speed specified by the IFCN bits. 1: Internal Oscillator Frequency running at speed specified by the IFCN bits. Bit3: CLKSL: System Clock Source Select Bit 0: Uses Internal Oscillator as System Clock. 1: Uses External Oscillator as System Clock. Bit2: IOSCEN: Internal Oscillator Enable Bit 0: Internal Oscillator Disabled 1: Internal Oscillator Enabled Bits1-0: IFCN1-0: Internal Oscillator Frequency Control Bits 00: Internal Oscillator typical frequency is 2MHz. 01: Internal Oscillator typical frequency is 4MHz. 10: Internal Oscillator typical frequency is 8MHz. 11: Internal Oscillator typical frequency is 16MHz.
Table 12.1. Internal Oscillator Electrical Characteristics
-40 C to +85 C unless otherwise specified. PARAMETER CONDITIONS Internal Oscillator OSCICN.[1:0] = 00 Frequency OSCICN.[1:0] = 01 OSCICN.[1:0] = 10 OSCICN.[1:0] = 11 Internal Oscillator Current OSCICN.2 = 1 Consumption (from VDD) Internal Oscillator Temperature Stability Internal Oscillator Power Supply (VDD) Stability MIN 1.5 3.1 6.2 12.3 TYP 2 4 8 16 200 4 6.4 MAX 2.4 4.8 9.6 19.2 UNITS MHz
A
ppm/ C %/V
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PRELIMINARY
Figure 12.3. OSCXCN: External Oscillator Control Register
R
XTLVLD
Bit7
R/W XOSCMD2 Bit6
R/W XOSCMD1 Bit5
R/W XOSCMD0 Bit4
R/W
R/W
R/W
R/W
Reset Value
Bit3
XFCN2
Bit2
XFCN1
Bit1
XFCN0
Bit0
00110000
SFR Address:
0xB1
XTLVLD: Crystal Oscillator Valid Flag (Valid only when XOSCMD = 1xx.) 0: Crystal Oscillator is unused or not yet stable 1: Crystal Oscillator is running and stable (should read 1ms after Crystal Oscillator is enabled to avoid transient condition). Bits6-4: XOSCMD2-0: External Oscillator Mode Bits 00x: Off. XTAL1 pin is grounded internally. 010: System Clock from External CMOS Clock on XTAL1 pin. 011: System Clock from External CMOS Clock on XTAL1 pin divided by 2. 10x: RC/C Oscillator Mode with divide by 2 stage. 110: Crystal Oscillator Mode 111: Crystal Oscillator Mode with divide by 2 stage. Bit3: RESERVED. Read = undefined, Write = don't care Bits2-0: XFCN2-0: External Oscillator Frequency Control Bits 000-111: see table below XFCN 000 001 010 011 100 101 110 111 Crystal (XOSCMD = 11x) f 12.5kHz 12.5kHz < f 30.3kHz 30.35kHz < f 93.8kHz 93.8kHz < f 267kHz 267kHz < f 722kHz 722kHz < f 2.23MHz 2.23MHz < f 6.74MHz f > 6.74MHz RC (XOSCMD = 10x) f 25kHz 25kHz < f 50kHz 50kHz < f 100kHz 100kHz < f 200kHz 200kHz < f 400kHz 400kHz < f 800kHz 800kHz < f 1.6MHz 1.6MHz < f 3.2MHz C (XOSCMD = 10x) K Factor = 0.44 K Factor = 1.4 K Factor = 4.4 K Factor = 13 K Factor = 38 K Factor = 100 K Factor = 420 K Factor = 1400
Bit7:
CRYSTAL MODE (Circuit from Figure 12.1, Option 1; XOSCMD = 11x) Choose XFCN value to match the crystal or ceramic resonator frequency. RC MODE (Circuit from Figure 12.1, Option 2; XOSCMD = 10x) Choose oscillation frequency range where: f = 1.23(103) / (R * C), where f = frequency of oscillation in MHz C = capacitor value in pF R = Pull-up resistor value in k C MODE (Circuit from Figure 12.1, Option 3; XOSCMD = 10x) Choose K Factor (KF) for the oscillation frequency desired: f = KF / (C * AV+), where f = frequency of oscillation in MHz C = capacitor value on XTAL1, XTAL2 pins in pF AV+ = Analog Power Supply on MCU in volts
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12.1. External Crystal Example
C8051F018 C8051F019
If a crystal or ceramic resonator were used to generate the system clock for the MCU, the circuit would be as shown in Figure 12.1, Option 1. For an ECS-110.5-20-4 crystal, the resonate frequency is 11.0592MHz, the intrinsic capacitance is 7pF, and the ESR is 60. The compensation capacitors should be 33pF each, and the PWB parasitic capacitance is estimated to be 2pF. The appropriate External Oscillator Frequency Control value (XFCN) from the Crystal column in the table in Figure 12.3 (OSCXCN Register) should be 111b. Because the oscillator detect circuitry needs time to settle after the crystal oscillator is enabled, software should wait at least 1ms between enabling the crystal oscillator and polling the XTLVLD bit. The recommend procedure is: 1. Enable the external oscillator 2. Wait at least 1 ms 3. Poll for XTLVLD '0' ==> '1' 4. Switch to the external oscillator Switching to the external oscillator before the crystal oscillator has stabilized could result in unpredictable behavior. NOTE: Crystal oscillator circuits are quite sensitive to PCB layout. The crystal should be placed as close as possible to the XTAL pins on the device, keeping the traces as short as possible and shielded with ground plane from any other traces which could introduce noise or interference.
12.2.
External RC Example
If an external RC network were used to generate the system clock for the MCU, the circuit would be as shown in Figure 12.1, Option 2. The capacitor must be no greater than 100pF, but using a very small capacitor will increase the frequency drift due to the PWB parasitic capacitance. To determine the required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, first select the RC network value to produce the desired frequency of oscillation. If the frequency desired is 100kHz, let R = 246k and C = 50pF: f = 1.23(103)/RC = 1.23(103) / [246 * 50] = 0.1MHz = 100kHz XFCN log2(f/25kHz) XFCN log2(100kHz/25kHz) = log2(4) XFCN 2, or code 010
12.3.
External Capacitor Example
If an external capacitor were used to generate the system clock for the MCU, the circuit would be as shown in Figure 12.1, Option 3. The capacitor must be no greater than 100pF, but using a very small capacitor will increase the frequency inaccuracy due to the PWB parasitic capacitance. To determine the required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, select the capacitor to be used and find the frequency of oscillation from the equations below. Assume AV+ = 3.0V and C = 50pF: f = KF / (C * VDD) = KF / (50 * 3) f = KF / 150 If a frequency of roughly 90kHz is desired, select the K Factor from the table in Figure 12.3 as KF = 13: f = 13 /150 = 0.087MHz, or 87kHz Therefore, the XFCN value to use in this example is 011.
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13. PORT INPUT/OUTPUT
PRELIMINARY
The MCUs have a wide array of digital resources, which are available through four digital I/O ports, P0, P1, P2 and P3. Each of the pins on Ports 0, 1, and 2 can be defined as either its corresponding port I/O or one of the internal digital resources assigned as shown in Figure 13.1. The designer has complete control over which functions are assigned, limited only by the number of physical I/O pins available on the selected package (the C8051F018 has all four ports pinned out, and the C8051F019 has P0 and P1). This resource assignment flexibility is achieved through the use of a Priority CrossBar Decoder. (Note that the state of a Port I/O pin can always be read in the corresponding Port latch regardless of the Crossbar settings). The CrossBar assigns the selected internal digital resources to the I/O pins based on the Priority Decode Table 13.1. The registers XBR0, XBR1, and XBR2, defined in Figure 13.3, Figure 13.4, and Figure 13.5 are used to select an internal digital function or let an I/O pin default to being a Port I/O. The crossbar functions identically for each MCU, with the caveat that P2 is not pinned out on the C8051F019. Digital resources assigned to port pins that are not pinned out cannot be accessed. All Port I/Os are 5V tolerant (Refer to Figure 13.2 for the port cell circuit.) The Port I/O cells are configured as either push-pull or open-drain in the Port Configuration Registers (PRT0CF, PRT1CF, PRT2CF, PRT3CF). Complete Electrical Specifications for Port I/O are given in Table 13.2.
13.1.
Priority Cross Bar Decoder
One of the design goals of this MCU family was to make the entire palette of digital resources available to the designer even on reduced pin count packages. The Priority CrossBar Decoder provides an elegant solution to the problem of connecting the internal digital resources to the physical I/O pins. The Priority CrossBar Decode (Table 13.1) assigns a priority to each I/O function, starting at the top with the SMBus. As the table illustrates, when selected, its two signals will be assigned to Pin 0 and 1 of I/O Port 0. The decoder always fills I/O bits from LSB to MSB starting with Port 0, then Port 1, finishing if necessary with Port 2. If you choose not to use a resource, the next function down on the table will fill the priority slot. In this way it is possible to choose only the functions required by the design, making full use of the available I/O pins. Also, any extra Port I/O are grouped together for more convenient use in application code. Registers XBR0, XBR1 and XBR2 are used to assign the digital I/O resources to the physical I/O Port pins. It is important to understand that when the SMBus, SPI Bus, or UART is selected, the crossbar assigns all pins associated with the selected bus. It would be impossible for instance to assign the RX pin from the UART function without also assigning the TX function. Standard Port I/Os appear contiguously after the prioritized functions have been assigned. For example, if you choose functions that take the first 14 Port I/O (P0.[7:0], P1.[5:0]), you would have 18 Port I/O left unused by the crossbar (P1.[7:6], P2 and P3).
13.2.
Port I/O Initialization
Port I/O initialization is straightforward. Registers XBR0, XBR1 and XBR2 must be loaded with the appropriate values to select the digital I/O functions required by the design. Setting the XBARE bit in XBR2 to 1 enables the CrossBar. Until the Crossbar is enabled, the external pins remain as standard Ports in input mode regardless of the XBRn Register settings. For given XBRn Register settings, one can determine the I/O pin-out using the Priority Decode Table; as an alternative, the Code Configuration Wizard function of the IDE software will determine the Port I/O pin-assignments based on the XBRn Register settings. The output driver characteristics of the I/O pins are defined using the Port Configuration Registers PRT0CF, PRT1CF, PRT2CF and PRT3CF (see Figure 13.7, Figure 13.9, Figure 13.12, and Figure 13.14). Each Port Output driver can be configured as either Open Drain or Push-Pull. This is required even for the digital resources selected in the XBRn registers and is not automatic. The only exception to this is the SMBus (SDA, SCL) and UART Receive (RX, when in mode 0) pins which are Open-drain regardless of the PRTnCF settings. When the WEAKPUD bit in XBR2 is 0, a weak pullup is enabled for all Port I/O configured as open-drain. WEAKPUD does
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not affect the push-pull Port I/O. Furthermore, the weak pullup is turned off on an open-drain output that is driving a 0 to avoid unnecessary power dissipation. The third and final step is to initialize the individual resources selected using the appropriate setup registers. Initialization procedures for the various digital resources may be found in the detailed explanation of each available function. The reset state of each register is shown in the figures that describe each individual register.
Figure 13.1. Port I/O Functional Block Diagram
Highest Priority SMBus SPI UART (Internal Digital Signals) PCA Comptr. Outputs T0, T1, T2, T2EX, /INT0, /INT1 /SYSCLK CNVSTR 8 P0 (P0.0-P0.7) 8 P1 Port Latches P2 (P1.0-P1.7) 8 (P2.0-P2.7) 8 P3 (P3.0-P3.7) P3 I/O Cells P3.0 P3.7 2 4 2 6 2 XBR0, XBR1, XBR2 Registers PRT0CF, PRT1CF, PRT2CF Registers External Pins
Priority Decoder
8 P0 I/O Cells P0.0 P0.7 Highest Priority
6
Digital Crossbar
8
Lowest Priority
P1 I/O Cells
P1.0 P1.7
8
P2 I/O Cells
P2.0 P2.7 Lowest Priority
PRT3CF Register
Figure 13.2. Port I/O Cell Block Diagram
WEAKPUD
PUSH-PULL /PORT-OUTENABLE
VDD
VDD
(WEAK) PORT PAD
PORT-OUTPUT
VDD PORT-INPUT
DGND
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P0 PIN I/O 0 SDA SCL SCK MISO MOSI NSS TX RX CEX0 CEX1 CEX2 CEX3 CEX4 ECI CP0 CP1 T0 /INT0 T1 /INT1 T2 T2EX /SYSCLK CNVSTR 1 2 3 4 5 6 7
PRELIMINARY
Table 13.1. Crossbar Priority Decode
P1 0 1 2 3 4 5 6 7 0 1 2 3 P2 4 5 6 7
G G
G G
G G G G G
G G G G G
G G G G
G G
G G G G
G G
G G G
G G G
G G
G G
G
GGGGG GGGGGGGGGGGGGG GGGGGGGGGGGGGGG GGGGGGGGGGGGGGGG GGGGGGGGGGGGGGGGG GGGGGGGGGGGGGGGGGG GGGGGGGGGGGGGGGGGGG GGGGGGGGGGGGGGGGGGGG GGGGGGGGGGGGGGGGGGGGG GGGGGGGGGGGGGGGGGGGGGG GGGGGGGGGGGGGGGGGGGGGGG GGGGGGGGGGGGGGGGGGGGGGGG
G
In the Priority Decode Table, a dot (*) is used to show the external Port I/O pin (column) to which each signal (row) can be assigned by the user application code via programming registers XBR2, XBR1, and XBR0.
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Figure 13.3. XBR0: Port I/O CrossBar Register 0
R/W R/W R/W Bit5 R/W R/W Bit3 R/W R/W
C8051F018 C8051F019
R/W
Reset Value
CP0OEN
Bit7
ECIE
Bit6
PCA0ME
Bit4
UARTEN
Bit2
SPI0OEN
Bit1
SMB0OEN
Bit0
00000000
SFR Address:
0xE1
CP0OEN: Comparator 0 Output Enable Bit 0: CP0 unavailable at Port pin. 1: CP0 routed to Port Pin. Bit6: ECIE: PCA0 Counter Input Enable Bit 0: ECI unavailable at Port pin. 1: ECI routed to Port Pin. Bits3-5: PCA0ME: PCA Module I/O Enable Bits 000: All PCA I/O unavailable at Port pins. 001: CEX0 routed to Port Pin. 010: CEX0, CEX1 routed to 2 Port Pins. 011: CEX0, CEX1, CEX2 routed to 3 Port Pins. 100: CEX0, CEX1, CEX2, CEX3 routed to 4 Port Pins. 101: CEX0, CEX1, CEX2, CEX3, CEX4 routed to 5 Port Pins. 110: RESERVED 111: RESERVED Bit2: UARTEN: UART I/O Enable Bit 0: UART I/O unavailable at Port pins. 1: RX, TX routed to 2 Port Pins. Bit1: SPI0OEN: SPI Bus I/O Enable Bit 0: SPI I/O unavailable at Port pins. 1: MISO, MOSI, SCK, and NSS routed to 4 Port Pins. Bit0: SMB0OEN: SMBus Bus I/O Enable Bit 0: SMBus I/O unavailable at P0.0, P0.1. 1: SDA routed to P0.0, SCL routed to P0.1.
Bit7:
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Figure 13.4. XBR1: Port I/O CrossBar Register 1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
SYSCKE
Bit7
T2EXE
Bit6
T2E
Bit5
INT1E
Bit4
T1E
Bit3
INT0E
Bit2
T0E
Bit1
CP1OEN
Bit0
00000000
SFR Address:
0xE2
Bit7: Bit6: Bit5: Bit4: Bit3: Bit2: Bit1: Bit0:
SYSCKE: SYSCLK Output Enable Bit 0: SYSCLK unavailable at Port pin. 1: SYSCLK output routed to Port Pin. T2EXE: T2EX Enable Bit 0: T2EX unavailable at Port pin. 1: T2EX routed to Port Pin. T2E: T2 Enable Bit 0: T2 unavailable at Port pin. 1: T2 routed to Port Pin. INT1E: /INT1 Enable Bit 0: /INT1 unavailable at Port pin. 1: /INT1 routed to Port Pin. T1E: T1 Enable Bit 0: T1 unavailable at Port pin. 1: T1 routed to Port Pin. INT0E: /INT0 Enable Bit 0: /INT0 unavailable at Port pin. 1: /INT0 routed to Port Pin. T0E: T0 Enable Bit 0: T0 unavailable at Port pin. 1: T0 routed to Port Pin. CP1OEN: Comparator 1 Output Enable Bit 0: CP1 unavailable at Port pin. 1: CP1 routed to Port Pin.
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Figure 13.5. XBR2: Port I/O CrossBar Register 2
R/W WEAKPUD Bit7 R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
XBARE
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
CNVSTE
Bit0
00000000
SFR Address:
0xE3
WEAKPUD: Port I/O Weak Pull-up Disable Bit 0: Weak Pull-ups Enabled (except for Ports whose I/O are configured as push-pull) 1: Weak Pull-ups Disabled Bit6: XBARE: Crossbar Enable Bit 0: Crossbar Disabled 1: Crossbar Enabled Bits5-1: UNUSED. Read = 00000b, Write = don't care. Bit0: CNVSTE: ADC Convert Start Input Enable Bit 0: CNVSTR unavailable at Port pin. 1: CNVSTR routed to Port Pin. Example Usage of XBR0, XBR1, XBR2: When selected, the digital resources fill the Port I/O pins in order (top to bottom as shown in Table 13.1) starting with P0.0 through P0.7, and then P1.0 through P1.7, and finally P2.0 through P2.7. If the digital resources are not mapped to the Port I/O pins, they default to their matching internal Port Register bits. Example1: If XBR0 = 0x11, XBR1 = 0x00, and XBR2 = 0x40: P0.0=SDA, P0.1=SCL, P0.2=CEX0, P0.3=CEX1, P0.4 ... P2.7 map to corresponding Port I/O. Example2: If XBR0 = 0x80, XBR1 = 0x04, and XBR2 = 0x41: P0.0=CP0, P0.1=/INT0, P0.2 = CNVSTR, P0.3 ... P2.7 map to corresponding Port I/O.
Bit7:
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13.3. General Purpose Port I/O
PRELIMINARY
Each MCU has four byte-wide, bi-directional parallel ports that can be used general purpose I/O. Each port is accessed through a corresponding special function register (SFR) that is both byte addressable and bit addressable. When writing to a port, the value written to the SFR is latched to maintain the output data value at each pin. When reading, the logic levels of the port's input pins are returned regardless of the XBRn settings (i.e. even when the pin is assigned to another signal by the Crossbar, the Port Register can always still read its corresponding Port I/O pin). The exception to this is the execution of the read-modify-write instructions. The read-modify-write instructions when operating on a port SFR are the following: ANL, ORL, XRL, JBC, CPL, INC, DEC, DJNZ and MOV, CLR or SET, when the destination is an individual bit in a port SFR. For these instructions, the value of the port register (not the pin) is read, modified, and written back to the SFR.
13.4.
Configuring Ports Which are not Pinned Out
P2 and P3 are not pinned out on the C8051F019. These port registers are still available for software use in the C8051F019. Whether used or not in software, it is recommended not to let these port drivers go to high impedance state. This is prevented after reset by having the weak pull-ups enabled as described in the XBR2 register. It is recommended that each output driver for ports not pinned out should be configured as push-pull using the corresponding PRTnCF register. This will inhibit a high impedance state even if the weak pull-up is disabled.
Figure 13.6. P0: Port0 Register
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
P0.7
Bit7
P0.6
Bit6
P0.5
Bit5
P0.4
Bit4
P0.3
Bit3
P0.2
Bit2
P0.1
Bit1
P0.0
Bit0
(bit addressable)
11111111
SFR Address:
0x80
Bits7-0: P0.[7:0] (Write - Output appears on I/O pins per XBR0, XBR1, and XBR2 Registers) 0: Logic Low Output. 1: Logic High Output (high-impedance if corresponding PRT0CF.n bit = 0) (Read - Regardless of XBR0, XBR1, and XBR2 Register settings). 0: P0.n pin is logic low. 1: P0.n pin is logic high.
Figure 13.7. PRT0CF: Port0 Configuration Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xA4
Bits7-0: PRT0CF.[7:0]: Output Configuration Bits for P0.7-P0.0 (respectively) 0: Corresponding P0.n Output mode is Open-Drain. 1: Corresponding P0.n Output mode is Push-Pull. (Note: When SDA, SCL, and RX appear on any of the P0 I/O, each are open-drain regardless of the value of PRT0CF).
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Figure 13.8. P1: Port1 Register
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
P1.7
Bit7
P1.6
Bit6
P1.5
Bit5
P1.4
Bit4
P1.3
Bit3
P1.2
Bit2
P1.1
Bit1
P1.0
Bit0
(bit addressable)
11111111
SFR Address:
0x90
Bits7-0: P1.[7:0] (Write - Output appears on I/O pins per XBR0, XBR1, and XBR2 registers) 0: Logic Low Output. 1: Logic High Output (high-impedance if corresponding PRT1CF.n bit = 0) (Read - Regardless of XBR0, XBR1, and XBR2 Register settings). 0: P1.n pin is logic low. 1: P1.n pin is logic high.
Figure 13.9. PRT1CF: Port1 Configuration Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xA5
Bits7-0: PRT1CF.[7:0]: Output Configuration Bits for P1.7-P1.0 (respectively) 0: Corresponding P1.n Output mode is Open-Drain. 1: Corresponding P1.n Output mode is Push-Pull.
Figure 13.10. PRT1IF: Port1 Interrupt Flag Register
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
IE7
Bit7
IE6
Bit6
IE5
Bit5
IE4
Bit4
Bit3
Bit2
Bit1
Bit0
00000000
SFR Address:
0xAD
Bit7:
IE7: External Interrupt 7 Pending Flag. 0: No falling edge detected on P1.7. 1: This flag is set by hardware when a falling edge on P1.7 is detected. Bit6: IE6: External Interrupt 6 Pending Flag. 0: No falling edge detected on P1.6. 1: This flag is set by hardware when a falling edge on P1.6 is detected. Bit5: IE5: External Interrupt 5 Pending Flag. 0: No falling edge detected on P1.5. 1: This flag is set by hardware when a falling edge on P1.5 is detected. Bit4: IE4: External Interrupt 4 Pending Flag. 0: No falling edge detected on P1.4. 1: This flag is set by hardware when a falling edge on P1.4 is detected. Bits3-0: UNUSED. Read = 0000b, Write = don't care.
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Figure 13.11. P2: Port2 Register
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
P2.7
Bit7
P2.6
Bit6
P2.5
Bit
P2.4
Bit4
P2.3
Bit3
P2.2
Bit2
P2.1
Bit1
P2.0
Bit0
(bit addressable)
11111111
SFR Address:
0xA0
Bits7-0: P2.[7:0] (Write - Output appears on I/O pins per XBR0, XBR1, and XBR2 registers) 0: Logic Low Output. 1: Logic High Output (high-impedance if corresponding PRT2CF.n bit = 0) (Read - Regardless of XBR0, XBR1, and XBR2 Register settings). 0: P2.n is logic low. 1: P2.n is logic high.
Figure 13.12. PRT2CF: Port2 Configuration Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xA6
Bits7-0: PRT2CF.[7:0]: Output Configuration Bits for P2.7-P2.0 (respectively) 0: Corresponding P2.n Output mode is Open-Drain. 1: Corresponding P2.n Output mode is Push-Pull.
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Figure 13.13. P3: Port3 Register
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
P3.7
Bit7
P3.6
Bit6
P3.5
Bit5
P3.4
Bit4
P3.3
Bit3
P3.2
Bit2
P3.1
Bit1
P3.0
Bit0
(bit addressable)
11111111
SFR Address:
0xB0
Bits7-0: P3.[7:0] (Write) 0: Logic Low Output. 1: Logic High Output (high-impedance if corresponding PRT3CF.n bit = 0) (Read) 0: P3.n is logic low. 1: P3.n is logic high.
Figure 13.14. PRT3CF: Port3 Configuration Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xA7
Bits7-0: PRT3CF.[7:0]: Output Configuration Bits for P3.7-P3.0 (respectively) 0: Corresponding P3.n Output mode is Open-Drain. 1: Corresponding P3.n Output mode is Push-Pull.
Table 13.2. Port I/O DC Electrical Characteristics
VDD = 2.8 to 3.6V, -40 C to +85 C unless otherwise specified. PARAMETER CONDITIONS Output High Voltage IOH = -10uA, Port I/O push-pull IOH = -3mA, Port I/O push-pull IOH = -10mA, Port I/O push-pull Output Low Voltage IOL = 10uA IOL = 8.5mA IOL = 25mA 0.7 x VDD 0.3 x VDD DGND < Port Pin < VDD, Pin Tri-state Weak Pull-up Off Weak Pull-up On
1
MIN VDD - 0.1 VDD - 0.7
TYP
MAX
UNITS V
VDD - 0.8 0.1 0.6 1.0 V V
A
V
Input High Voltage Input Low Voltage Input Leakage Current
Capacitive Loading
30 5
pF
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14. SMBus / I2C Bus
PRELIMINARY
The SMBus serial I/O interface is compliant with the System Management Bus Specification, version 1.1. It is a two-wire, bi-directional serial bus, which is also compatible with the I2C serial bus. Reads and writes to the interface by the system controller are byte oriented with the SMBus interface autonomously controlling the serial transfer of the data. Data can be transferred at up to 1/8th of the system clock if desired (this can be faster than allowed by the SMBus specification, depending on the system clock used). A method of extending the clock-low duration is used to accommodate devices with different speed capabilities on the same bus. Two types of data transfers are possible: data transfers from a master transmitter to an addressed slave receiver, and data transfers from an addressed slave transmitter to a master receiver. The master device initiates both types of data transfers and provides the serial clock pulses. The SMBus interface may operate as a master or a slave. Multiple master devices on the same bus are also supported. If two or more masters attempt to initiate a data transfer simultaneously, an arbitration scheme is employed with a single master always winning the arbitration.
Figure 14.1. SMBus Block Diagram
SFR Bus
SMB0CN
B U S Y ESSSAFT NTT IATO SAO EE M B S T A 7 S T A 6
SMB0STA
S T A 5 S T A 4 S T A 3 S T A 2 S T A 1 S T A 0
SMB0CR
CCCCCCCC RRRRRRRR 76543210
Clock Divide Logic
SYSCLK
FILTER
SCL
SMBUS CONTROL LOGIC
SMBUS IRQ
Interrupt Request Arbitration SCL Synchronization Status Generation SCL Generation (Master Mode) IRQ Generation
SCL Control
Data Path Control
N
SDA Control
B
A
B
A
C R O S S B A R
Port I/O
A=B
A=B 0000000b 7 MSBs 8
7
SMB0DAT 76543210
8 8 1
FILTER
SDA
S L V 6
S L V 5
S L V 4
S L V 3
S L V 2
S L V 1
S L VG 0C
N 0 Read SMB0DAT Write to SMB0DAT
SMB0ADR
SFR Bus
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Figure 14.2 shows a typical SMBus configuration. The SMBus interface will work at any voltage between 3.0V and 5.0V and different devices on the bus may operate at different voltage levels. The SCL (serial clock) and SDA (serial data) lines are bi-directional. They must be connected to a positive power supply voltage through a pull-up resistor or similar circuit. When the bus is free, both lines are pulled high. Every device connected to the bus must have an open-drain or open-collector output for both the SCL and SDA lines. The maximum number of devices on the bus is limited only by the requirement that the rise and fall times on the bus will not exceed 300ns and 1000ns, respectively.
Figure 14.2. Typical SMBus Configuration
VDD = 5V VDD = 3V VDD = 5V VDD = 3V
Master Device
Slave Device 1
Slave Device 2
SDA SCL
14.1.
Supporting Documents
It is assumed the reader is familiar with or has access to the following supporting documents: 1. The I2C-bus and how to use it (including specifications), Philips Semiconductor. 2. The I2C-Bus Specification -- Version 2.0, Philips Semiconductor. 3. System Management Bus Specification -- Version 1.1, SBS Implementers Forum.
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14.2. Operation
PRELIMINARY
A typical SMBus transaction consists of a START condition, followed by an address byte, one or more bytes of data, and a STOP condition. The address byte and each of the data bytes are followed by an ACKNOWLEDGE bit from the receiver. The address byte consists of a 7-bit address plus a direction bit. The direction bit (R/W) occupies the least-significant bit position of the address. The direction bit is set to logic 1 to indicate a "READ" operation and cleared to logic 0 to indicate a "WRITE" operation. A general call address (0x00 +R/W) is recognized by all slave devices allowing a master to address multiple slave devices simultaneously. All transactions are initiated by the master, with one or more addressed slave devices as the target. The master generates the START condition and then transmits the address and direction bit. If the transaction is a WRITE operation from the master to the slave, the master transmits the data a byte at a time waiting for an ACKNOWLEDGE from the slave at the end of each byte. If it is a READ operation, the slave transmits the data waiting for an ACKNOWLEDGE from the master at the end of each byte. At the end of the data transfer, the master generates a STOP condition to terminate the transaction and free the bus. Figure 14.3 illustrates a typical SMBus transaction.
Figure 14.3. SMBus Transaction
START
SLAVE ADDR
R/W
ACK
DATA
ACK
DATA
NACK
STOP
Time
The SMBus interface may be configured to operate as either a master or a slave. At any particular time, it will be operating in one of the following four modes:
14.2.1. Master Transmitter Mode
Serial data is transmitted on SDA while the serial clock is output on SCL. The first byte transmitted contains the address of the target slave device and the data direction bit. In this case the data direction bit (R/W) will be logic 0 to indicate a "WRITE" operation. The master then transmits one or more bytes of serial data. After each byte is transmitted, an acknowledge bit is generated by the slave. To indicate the beginning and the end of the serial transfer, the master device outputs START and STOP conditions.
14.2.2. Master Receiver Mode
Serial data is received on SDA while the serial clock is output on SCL. The first byte is transmitted by the master and contains the address of the target slave and the data direction bit. In this case the data direction bit (R/W) will be logic 1 to indicate a "READ" operation. Serial data is then received from the slave on SDA while the master outputs the serial clock. The slave transmits one or more bytes of serial data. After each byte is received, an acknowledge bit is transmitted by the master. The master outputs START and STOP conditions to indicate the beginning and end of the serial transfer.
14.2.3. Slave Transmitter Mode
Serial data is transmitted on SDA while the serial clock is received on SCL. First, a byte is received that contains an address and data direction bit. In this case the data direction bit (R/W) will be logic 1 to indicate a "READ" operation. If the received address matches the slave's assigned address (or a general call address is received) one or more bytes of serial data are transmitted to the master. After each byte is received, an acknowledge bit is transmitted by the master. The master outputs START and STOP conditions to indicate the beginning and end of the serial transfer.
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14.2.4. Slave Receiver Mode
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Serial data is received on SDA while the serial clock is received on SCL. First, a byte is received that contains an address and data direction bit. In this case the data direction bit (R/W) will be logic 0 to indicate a "WRITE" operation. If the received address matches the slave's assigned address (or a general call address is received) one or more bytes of serial data are received from the master. After each byte is received, an acknowledge bit is transmitted by the slave. The master outputs START and STOP conditions to indicate the beginning and end of the serial transfer.
14.3.
Arbitration
A master may start a transfer only if the bus is free. The bus is free after a STOP condition or after the SCL and SDA lines remains high for a specified time. Two or more master devices may attempt to generate a START condition at the same time. Since the devices that generated the START condition may not be aware that other masters are contending for the bus, an arbitration scheme is employed. The master devices continue to transmit until one of the masters transmits a HIGH level, while the other(s) master transmits a LOW level on SDA. The first master(s) transmitting the HIGH level on SDA looses the arbitration and is required to give up the bus.
14.4.
Clock Low Extension
SMBus provides a clock synchronization mechanism, similar to I2C, which allows devices with different speed capabilities to coexist on the bus. A clock-low extension is used during a transfer in order to allow slower slave devices to communicate with faster masters. The slave can hold the SCL line LOW to extend the clock low period, effectively decreasing the serial clock frequency.
14.5.
Timeouts
14.5.1. SCL Low Timeout
If the SCL line is held low by a slave device on the bus, no further communication is possible. Furthermore, the master cannot force the SCL line high to correct the error condition. To solve this problem, the SMBus protocol specifies that devices participating in a transfer must detect any clock cycle held low longer than 25ms as a "timeout" condition. Devices that have detected the timeout condition must reset the communication no later than 10ms after detecting the timeout condition. One of the MCU's general-purpose timers, operating in 16-bit auto-reload mode, can be used to monitor the SCL line for this timeout condition. Timer 3 is specifically designed for this purpose. (Refer to the Timer 3 Section 17.3. for detailed information on Timer 3 operation.)
14.5.2. SCL High (SMBus Free) Timeout
The SMBus specification stipulates that if a device holds the SCL and SDA lines high for more that 50usec, the bus is designated as free. The SMB0CR register is used to detect this condition when the FTE bit in SMB0CN is set.
14.6.
SMBus Special Function Registers
The SMBus serial interface is accessed and controlled through five SFRs: SMB0CN Control Register, SMB0CR Clock Rate Register, SMB0ADR Address Register, SMB0DAT Data Register and SMB0STA Status Register. The system device may have one or more SMBus serial interfaces implemented. The five special function registers related to the operation of the SMBus interface are described in the following section.
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14.6.1. Control Register
PRELIMINARY
The SMBus Control register SMB0CN is used to configure and control the SMBus interface. All of the bits in the register can be read or written by software. Two of the control bits are also affected by the SMBus hardware. The Serial Interrupt flag (SI, SMB0CN.3) is set to logic 1 by the hardware when a valid serial interrupt condition occurs. It can only be cleared by software. The Stop flag (STO, SMB0CN.4) is cleared to logic 0 by hardware when a STOP condition is present on the bus. Setting the ENSMB flag to logic 1 enables the SMBus interface. Clearing the ENSMB flag to logic 0 disables the SMBus interface and removes it from the bus. Momentarily clearing the ENSMB flag and then resetting it to logic 1 will reset a SMBus communication. However, ENSMB should not be used to temporarily remove a device from the bus since the bus state information will be lost. Instead, the Assert Acknowledge (AA) flag should be used to temporarily remove the device from the bus (see description of AA flag below). Setting the Start flag (STA, SMB0CN.5) to logic 1 will put the SMBus in a master mode. If the bus is free, the SMBus hardware will generate a START condition. If the bus is not free, the SMBus hardware waits for a STOP condition to free the bus and then generates a START condition after a 5s delay per the SMB0CR value. (In accordance with the SMBus protocol, the SMBus interface also considers the bus free if the bus is idle for 50s and no STOP condition was recognized.) If STA is set to logic 1 while the SMBus is in master mode and one or more bytes have been transferred, a repeated START condition will be generated. To ensure proper operation, the STO flag should be explicitly cleared before setting STA to a logic 1. When the Stop flag (STO, SMB0CN.4) is set to logic 1 while the SMBus interface is in master mode, the hardware generates a STOP condition on the SMBus. In a slave mode, the STO flag may be used to recover from an error condition. In this case, a STOP condition is not generated on the SMBus, but the SMBus hardware behaves as if a STOP condition has been received and enters the "not addressed" slave receiver mode. The SMBus hardware automatically clears the STO flag to logic 0 when a STOP condition is detected on the bus. The Serial Interrupt flag (SI, SMB0CN.3) is set to logic 1 by hardware when the SMBus interface enters one of 27 possible states. If interrupts are enabled for the SMBus interface, an interrupt request is generated when the SI flag is set. The SI flag must be cleared by software. While SI is set to logic 1, the clock-low period of the serial clock will be stretched and the serial transfer is suspended. The Assert Acknowledge flag (AA, SMB0CN.2) is used to set the level of the SDA line during the acknowledge clock cycle on the SCL line. Setting the AA flag to logic 1 will cause an ACKNOWLEDGE (low level on SDA) to be sent during the acknowledge cycle if the device has been addressed. Setting the AA flag to logic 0 will cause a NOT ACKNOWLEDGE (high level on SDA) to be sent during acknowledge cycle. After the transmission of a byte in slave mode, the slave can be temporarily removed from the bus by clearing the AA flag. The slave's own address and general call address will be ignored. To resume operation on the bus, the AA flag must be reset to logic 1 to allow the slave's address to be recognized. Setting the SMBus Free Timer Enable bit (FTE, SMB0CN.1) to logic 1 enables the SMBus Free Timeout feature. If SCL and SDA remain high for the SMBus Free Timeout given in the SMBus Clock Rate Register (Figure 14.5), the bus will be considered free and a Start will be generated if pending. The bus free period should be greater than 50s. Setting the SMBus timeout enable bit (TOE, SMB0CN.0) to logic 1 enables Timer 3 to count up when the SCL line is low and Timer 3 is enabled. If Timer 3 overflows, a Timer 3 interrupt will be generated, which will alert the CPU that a SMBus SCL low timeout has occurred.
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Figure 14.4. SMB0CN: SMBus Control Register
R R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
BUSY
Bit7
ENSMB
Bit6
STA
Bit5
STO
Bit4
SI
Bit3
AA
Bit2
FTE
Bit1
TOE
Bit0
(bit addressable)
00000000
SFR Address:
0xC0
Bit7: Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1: Bit0:
BUSY: Busy Status Flag. 0: SMBus is free 1: SMBus is busy ENSMB: SMBus Enable. This bit enables/disables the SMBus serial interface. 0: SMBus disabled. 1: SMBus enabled. STA: SMBus Start Flag. 0: No START condition is transmitted. 1: When operating as a master, a START condition is transmitted if the bus is free. (If the bus is not free, the START is transmitted after a STOP is received.) If STA is set after one or more bytes have been transmitted or received and before a STOP is received, a repeated START condition is transmitted. STO should be explicitly cleared before setting STA to logic 1. STO: SMBus Stop Flag. 0: No STOP condition is transmitted. 1: Setting STO to logic 1 causes a STOP condition to be transmitted. When a STOP condition is received, hardware clears STO to logic 0. If both STA and STO are set, a STOP condition is transmitted followed by a START condition. In slave mode, setting the STO flag causes SMBus to behave as if a STOP condition was received. SI: SMBus Serial Interrupt Flag. This bit is set by hardware when one of 27 possible SMBus states is entered. (Status code 0xF8 does not cause SI to be set.) When the SI interrupt is enabled, setting this bit causes the CPU to vector to the SMBus interrupt service routine. This bit is not automatically cleared by hardware and must be cleared by software. AA: SMBus Assert Acknowledge Flag. This bit defines the type of acknowledge returned during the acknowledge cycle on the SCL line. 0: A "not acknowledge" (high level on SDA) is returned during the acknowledge cycle. 1: An "acknowledge" (low level on SDA) is returned during the acknowledge cycle. FTE: SMBus Free Timer Enable Bit 0: No timeout when SCL is high 1: Timeout when SCL high time exceeds limit specified by the SMB0CR value. TOE: SMBus Timeout Enable Bit 0: No timeout when SCL is low. 1: Timeout when SCL low time exceeds limit specified by Timer 3, if enabled.
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14.6.2. Clock Rate Register
PRELIMINARY
Figure 14.5. SMB0CR: SMBus Clock Rate Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xCF
Bits7-0: SMB0CR.[7:0]: SMBus Clock Rate Preset The SMB0CR Clock Rate register controls the frequency of the serial clock SCL in master mode. The 8-bit word stored in the SMB0CR Register preloads a dedicated 8-bit timer. The timer counts up, and when it rolls over to 0x00, the SCL logic state toggles. The period of the SCL clock is given in the following equation: TH = TL = TSYSCLK * [(256 - SMB0CR) + 2.5] 5s Using the same value of SMB0CR from above, the Bus Free Timeout period is given in the following equation: TBFT = TSYSCLK * [10*(256 - SMB0CR) + 1] 50s Any value 0x00 through 0xFE may be used for the SMBus Clock Rate Register. The value 0xFF should not be used.
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14.6.3. Data Register
C8051F018 C8051F019
The SMBus Data register SMB0DAT holds a byte of serial data to be transmitted or one that has just been received. Data remains stable in the register as long as SI is set to logic 1. Software can safely read or write to the data register when the SI flag is set. Software should not attempt to access the SMB0DAT register when the SMBus is enabled and the SI flag is cleared to logic 0 since the hardware may be in the process of shifting a byte of data in or out of the register. Data in SMB0DAT is always shifted out MSB first. After a byte has been received, the first bit of received data is located at the MSB of SMB0DAT. While data is being shifted out, data on the bus is simultaneously being shifted in. Therefore, SMB0DAT always contains the last data byte present on the bus. Thus, in the event of lost arbitration, the transition from master transmitter to slave receiver is made with the correct data in SMB0DAT.
Figure 14.6. SMB0DAT: SMBus Data Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xC2
Bits7-0: SMB0DAT: SMBus Data. The SMB0DAT register contains a byte of data to be transmitted on the SMBus serial interface or a byte that has just been received on the SMBus serial interface. The CPU can read from or write to this register whenever the SI serial interrupt flag (SMB0CN.3) is set to logic one. The serial data in the register remains stable as long as the SI flag is set. When the SI flag is not set, the system may be in the process of shifting data in/out and the CPU should not attempt to access this register.
14.6.4. Address Register
The SMB0ADR Address register holds the slave address for the SMBus interface. In slave mode, the seven mostsignificant bits hold the 7-bit slave address. The least significant bit, bit 0, is used to enable the recognition of the general call address (0x00). If bit 0 is set to logic 1, the general call address will be recognized. Otherwise, the general call address is ignored. The contents of this register are ignored when the SMBus hardware is operating in master mode.
Figure 14.7. SMB0ADR: SMBus Address Register
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
SLV6
Bit7
SLV5
Bit6
SLV4
Bit5
SLV3
Bit4
SLV2
Bit3
SLV1
Bit2
SLV0
Bit1
GC
Bit0
00000000
SFR Address:
0xC3
Bits7-1: SLV6-SLV0: SMBus Slave Address. These bits are loaded with the 7-bit slave address to which the SMBus will respond when operating as a slave transmitter or slave receiver. SLV6 is the most significant bit of the address and corresponds to the first bit of the address byte received on the SMBus. Bit0: GC: General Call Address Enable. This bit is used to enable general call address (0x00) recognition. 0: General call address is ignored. 1: General call address is recognized.
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14.6.5. Status Register
PRELIMINARY
The SMB0STA Status register holds an 8-bit status code indicating the current state of the SMBus. There are 28 possible SMBus states, each with a corresponding unique status code. The five most significant bits of the status code vary while the three least-significant bits of a valid status code are fixed at zero when SI = 1. Therefore, all possible status codes are multiples of eight. This facilitates the use of status codes in software as an index used to branch to appropriate service routines (allowing 8 bytes of code to service the state or jump to a more extensive service routine). For the purposes of user software, the contents of the SMB0STA register is only defined when the SI flag is logic 1. Software should never write to the SMB0STA register. Doing so will yield indeterminate results. The 28 SMBus states, along with their corresponding status codes, are given in Table 14.1.
Figure 14.8. SMB0STA: SMBus Status Register
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
STA7
Bit7
STA6
Bit6
STA5
Bit5
STA4
Bit4
STA3
Bit3
STA2
Bit2
STA1
Bit1
STA0
Bit0
11111000
SFR Address:
0xC1
Bits7-3: STA7-STA3: SMBus Status Code. These bits contain the SMBus Status Code. There are 28 possible status codes. Each status code corresponds to a single SMBus state. A valid status code is present in SMB0STA when the SI flag (SMB0CN.3) is set. The content of SMB0STA is not defined when the SI flag is logic 0. Writing to the SMB0STA register at any time will yield indeterminate results. Bits2-0: STA2-STA0: The three least significant bits of SMB0STA are always read as logic 0 when the SI flag is logic 1.
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Table 14.1. SMBus Status Codes
Status Code (SMB0STA) 0x00 0x08 0x10 0x18 0x20 0x28 0x30 0x38 0x40 0x48 0x50 0x58 0x60 0x68 0x70 0x78 0x80 0x88 0x90 0x98 0xA0 0xA8 0xB0 0xB8 0xC0 0xC8 0xD0 0xF8 Mode All Master Transmitter/Receiver Master Transmitter/Receiver Master Transmitter Master Transmitter Master Transmitter Master Transmitter Master Transmitter Master Receiver Master Receiver Master Receiver Master Receiver Slave Receiver Slave Receiver Slave Receiver Slave Receiver Slave Receiver Slave Receiver Slave Receiver Slave Receiver Slave Receiver Slave Transmitter Slave Transmitter Slave Transmitter Slave Transmitter Slave Transmitter Slave Transmitter/Receiver All SMBus State
C8051F018 C8051F019
Bus Error (i.e. illegal START, illegal STOP, ...) START condition transmitted. Repeated START condition transmitted. Slave address + W transmitted. ACK received. Slave address + W transmitted. NACK received. Data byte transmitted. ACK received. Data byte transmitted. NACK received. Arbitration lost Slave address + R transmitted. ACK received. Slave address + R transmitted. NACK received Data byte received. ACK transmitted. Data byte received. NACK transmitted. SMB0's own slave address + W received. ACK transmitted. Arbitration lost in transmitting slave address + R/W as master. Own slave address + W received. ACK transmitted. General call address (0x00) received. ACK returned. Arbitration lost in transmitting slave address + R/W as master. General call address received. ACK transmitted. SMB0's own slave address + W received. Data byte received. ACK transmitted. SMB0's own slave address + W received. Data byte received. NACK transmitted. General call address (0x00) received. Data byte received. ACK transmitted. General call address (0x00) received. Data byte received. NACK transmitted. A STOP or repeated START received while addressed as a slave. SMB0's own slave address + R received. ACK transmitted. Arbitration lost in transmitting slave address + R/W as master. Own slave address + R received. ACK transmitted. Data byte transmitted. ACK received. Data byte transmitted. NACK received. Last data byte transmitted (AA=0). ACK received. SCL Clock High Timer per SMB0CR timed out (FTE=1) Idle
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PRELIMINARY
15. SERIAL PERIPHERAL INTERFACE BUS
The Serial Peripheral Interface (SPI) provides access to a four-wire, full-duplex, serial bus. SPI supports the connection of multiple slave devices to a master device on the same bus. A separate slave-select signal (NSS) is used to select a slave device and enable a data transfer between the master and the selected slave. Multiple masters on the same bus are also supported. Collision detection is provided when two or more masters attempt a data transfer at the same time. The SPI can operate as either a master or a slave. When the SPI is configured as a master, the maximum data transfer rate (bits/sec) is one-half the system clock frequency. When the SPI is configured as a slave, the maximum data transfer rate (bits/sec) for full-duplex operation is 1/10 the system clock frequency, provided that the master issues SCK, NSS, and the serial input data synchronously with the system clock. If the master issues SCK, NSS, and the serial input data asynchronously, the maximum data transfer rate (bits/sec) must be less that 1/10 the system clock frequency. In the special case where the master only wants to transmit data to the slave and does not need to receive data from the slave (i.e. half-duplex operation), the SPI slave can receive data at a maximum data transfer rate (bits/sec) of 1/4 the system clock frequency. This is provided that the master issues SCK, NSS, and the serial input data synchronously with the system clock.
Figure 15.1. SPI Block Diagram
SFR Bus
SPI0CKR
S C R 7 S C R 6 S C R 5 S C R 4 S C R 3 S C R 2 S C R 1 S C R 0 C K P H A
SPI0CFG
CBBBF KCCCR P210S O 2 L F R S 1 F R S 0 S P I F W C O L
SPI0CN
M O D F R X O V R N T X B S Y S L V S E L M S T E N S P I E N
SYSCLK
Clock Divide Logic
Bit Count Logic
SPI CONTROL LOGIC
Data Path Control SPI Clock (Master Mode) Pin Control Interface
SPI IRQ
SCK
Tx Data
MOSI Pin Control Logic
SPI0DAT
Shift Register
76543210
Rx Data
MISO
C R O S S B A R
Port I/O
Receive Data Register
NSS
Write to SPI0DAT
Read SPI0DAT
SFR Bus
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Figure 15.2. Typical SPI Interconnection
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NSS
NSS
NSS
Slave Device
Port I/O Port I/O Port I/O
Slave Device
Slave Device
VDD
Master Device
15.1. Signal Descriptions
MISO MOSI SCK
The four signals used by the SPI (MOSI, MISO, SCK, NSS) are described below.
15.1.1. Master Out, Slave In
The master-out, slave-in (MOSI) signal is an output from a master device and an input to slave devices. It is used to serially transfer data from the master to the slave. Data is transferred most-significant bit first.
15.1.2. Master In, Slave Out
The master-in, slave-out (MISO) signal is an output from a slave device and an input to the master device. It is used to serially transfer data from the slave to the master. Data is transferred most-significant bit first. A SPI slave places the MISO pin in a high-impedance state when the slave is not selected.
15.1.3. Serial Clock
The serial clock (SCK) signal is an output from the master device and an input to slave devices. It is used to synchronize the transfer of data between the master and slave on the MOSI and MISO lines.
15.1.4. Slave Select
The slave select (NSS) signal is an input used to select the SPI module when in slave mode by a master, or to disable the SPI module when in master mode. When in slave mode, it is pulled low to initiate a data transfer and remains low for the duration of the transfer.
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15.2. Operation
PRELIMINARY
Only a SPI master device can initiate a data transfer. The SPI is placed in master mode by setting the Master Enable flag (MSTEN, SPI0CN.1). Writing a byte of data to the SPI data register (SPI0DAT) when in Master Mode starts a data transfer. The SPI master immediately shifts out the data serially on the MOSI line while providing the serial clock on SCK. The SPIF (SPI0CN.7) flag is set to logic 1 at the end of the transfer. If interrupts are enabled, an interrupt request is generated when the SPIF flag is set. The SPI master can be configured to shift in/out from one to eight bits in a transfer operation in order to accommodate slave devices with different word lengths. The SPIFRS bits in the SPI Configuration Register (SPI0CFG.[2:0]) are used to select the number of bits to shift in/out in a transfer operation. While the SPI master transfers data to a slave on the MOSI line, the addressed SPI slave device simultaneously transfers the contents of its shift register to the SPI master on the MISO line in a full-duplex operation. The data byte received from the slave replaces the data in the master's data register. Therefore, the SPIF flag serves as both a transmit-complete and receive-data-ready flag. The data transfer in both directions is synchronized with the serial clock generated by the master. Figure 15.3 illustrates the full-duplex operation of an SPI master and an addressed slave.
Figure 15.3. Full Duplex Operation
MASTER DEVICE
MOSI MOSI
SLAVE DEVICE
SPI SHIFT REGISTER
76543210
MISO
MISO
SPI SHIFT REGISTER
76543210
VDD
Receive Buffer
NSS
NSS
Receive Buffer
Baud Rate Generator
SCK
SCK
Px.y
The SPI data register is double buffered on reads, but not on a write. If a write to SPI0DAT is attempted during a data transfer, the WCOL flag (SPI0CN.6) will be set to logic 1 and the write is ignored. The current data transfer will continue uninterrupted. A read of the SPI data register by the system controller actually reads the receive buffer. If the receive buffer still holds unread data from a previous transfer when the last bit of the current transfer is shifted into the SPI shift register, a receive overrun occurs and the RXOVRN flag (SPI0CN.4) is set to logic 1. The new data is not transferred to the receive buffer, allowing the previously received data byte to be read. The data byte causing the overrun is lost. When the SPI is enabled and not configured as a master, it will operate as an SPI slave. Another SPI device acting as a master will initiate a transfer by driving the NSS signal low. The master then shifts data out of the shift register on the MOSI pin using the its serial clock. The SPIF flag is set to logic 1 at the end of a data transfer (when the NSS signal goes high). The slave can load its shift register for the next data transfer by writing to the SPI data register. The slave must make the write to the data register at least one SPI serial clock cycle before the master starts the next transmission. Otherwise, the byte of data already in the slave's shift register will be transferred. Multiple masters may reside on the same bus. A Mode Fault flag (MODF, SPI0CN.5) is set to logic 1 when the SPI is configured as a master (MSTEN = 1) and its slave select signal NSS is pulled low. When the Mode Fault flag is set, the MSTEN and SPIEN bits of the SPI control register are cleared by hardware, thereby placing the SPI module
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in an "off-line" state. In a multiple-master environment, the system controller should check the state of the SLVSEL flag (SPI0CN.2) to ensure the bus is free before setting the MSTEN bit and initiating a data transfer.
15.3.
Serial Clock Timing
As shown in Figure 15.4, four combinations of serial clock phase and polarity can be selected using the clock control bits in the SPI Configuration Register (SPI0CFG). The CKPHA bit (SPI0CFG.7) selects one of two clock phases (edge used to latch the data). The CKPOL bit (SPI0CFG.6) selects between an active-high or active-low clock. Both master and slave devices must be configured to use the same clock phase and polarity. Note: the SPI should be disabled (by clearing the SPIEN bit, SPI0CN.0) while changing the clock phase and polarity. The SPI Clock Rate Register (SPI0CKR) as shown in Figure 15.7 controls the master mode serial clock frequency. This register is ignored when operating in slave mode.
Figure 15.4. Data/Clock Timing Diagram
SCK (CKPOL = 0, CKPHA = 0)
SCK (CKPOL = 0, CKPHA = 1)
SCK (CKPOL = 1, CKPHA = 0)
SCK (CKPOL = 1, CKPHA = 1) MISO/MOSI MSB Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 LSB
NSS
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15.4.
PRELIMINARY
SPI Special Function Registers
The SPI is accessed and controlled through four special function registers in the system controller: SPI0CN Control Register, SPI0DAT Data Register, SPI0CFG Configuration Register, and SPI0CKR Clock Rate Register. The four special function registers related to the operation of the SPI Bus are described in the following section.
Figure 15.5. SPI0CFG: SPI Configuration Register
R/W R/W R R R R/W R/W R/W Reset Value
CKPHA
Bit7
CKPOL
Bit6
BC2
Bit5
BC1
Bit4
BC0
Bit3
SPIFRS2
Bit2
SPIFRS1
Bit1
SPIFRS0
Bit0
00000111
SFR Address:
0x9A
Bit7:
CKPHA: SPI Clock Phase. This bit controls the SPI clock phase. 0: Data sampled on first edge of SCK period. 1: Data sampled on second edge of SCK period. CKPOL: SPI Clock Polarity. This bit controls the SPI clock polarity. 0: SCK line low in idle state. 1: SCK line high in idle state.
Bit6:
Bits5-3: BC2-BC0: SPI Bit Count. Indicates which of the up to 8 bits of the SPI word have been transmitted. BC2-BC0 0 0 1 1 0 0 1 1 Bit Transmitted Bit 0 (LSB) Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 (MSB)
0 0 0 0 1 1 1 1
0 1 0 1 0 1 0 1
Bits2-0: SPIFRS2-SPIFRS0: SPI Frame Size. These three bits determine the number of bits to shift in/out of the SPI shift register during a data transfer in master mode. They are ignored in slave mode. SPIFRS 0 0 1 1 0 0 1 1 Bits Shifted 1 2 3 4 5 6 7 8
0 0 0 0 1 1 1 1 .
0 1 0 1 0 1 0 1
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Figure 15.6. SPI0CN: SPI Control Register
R/W R/W R/W R/W R R R/W
C8051F018 C8051F019
R/W
Reset Value
SPIF
Bit7
WCOL
Bit6
MODF
Bit5
RXOVRN
Bit4
TXBSY
Bit3
SLVSEL
Bit2
MSTEN
Bit1
SPIEN
Bit0
(bit addressable)
00000000
SFR Address:
0xF8
Bit7:
SPIF: SPI Interrupt Flag. This bit is set to logic 1 by hardware at the end of a data transfer. If interrupts are enabled, setting this bit causes the CPU to vector to the SPI0 interrupt service routine. This bit is not automatically cleared by hardware. It must be cleared by software. WCOL: Write Collision Flag. This bit is set to logic 1 by hardware (and generates a SPI interrupt) to indicate a write to the SPI data register was attempted while a data transfer was in progress. It is cleared by software. MODF: Mode Fault Flag. This bit is set to logic 1 by hardware (and generates a SPI interrupt) when a master mode collision is detected (NSS is low and MSTEN = 1). This bit is not automatically cleared by hardware. It must be cleared by software. RXOVRN: Receive Overrun Flag. This bit is set to logic 1 by hardware (and generates a SPI interrupt) when the receive buffer still holds unread data from a previous transfer and the last bit of the current transfer is shifted into the SPI shift register. This bit is not automatically cleared by hardware. It must be cleared by software. TXBSY: Transmit Busy Flag. This bit is set to logic 1 by hardware while a master mode transfer is in progress. It is cleared by hardware at the end of the transfer. SLVSEL: Slave Selected Flag. This bit is set to logic 1 whenever the NSS pin is low indicating it is enabled as a slave. It is cleared to logic 0 when NSS is high (slave disabled). MSTEN: Master Mode Enable. 0: Disable master mode. Operate in slave mode. 1: Enable master mode. Operate as a master. SPIEN: SPI Enable. This bit enables/disables the SPI. 0: SPI disabled. 1: SPI enabled.
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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Figure 15.7. SPI0CKR: SPI Clock Rate Register
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
SCR7
Bit7
SCR6
Bit6
SCR5
Bit5
SCR4
Bit4
SCR3
Bit3
SCR2
Bit2
SCR1
Bit1
SCR0
Bit0
00000000
SFR Address:
0x9D
Bits7-0: SCR7-SCR0: SPI Clock Rate These bits determine the frequency of the SCK output when the SPI module is configured for master mode operation. The SCK clock frequency is a divided down version of the system clock, and is given in the following equations: fSCK = 0.5 * fSYSCLK / (SPI0CKR + 1), for 0 SPI0CKR 255,
Figure 15.8. SPI0DAT: SPI Data Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0x9B
Bits7-0: SPI0DAT: SPI0 Transmit and Receive Data. The SPI0DAT register is used to transmit and receive SPI data. Writing data to SPI0DAT places the data immediately into the shift register and initiates a transfer when in Master Mode. A read of SPI0DAT returns the contents of the receive buffer.
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16. UART
C8051F018 C8051F019
The UART is a serial port capable of asynchronous transmission. The UART can function in full duplex mode. In all modes, receive data is buffered in a holding register. This allows the UART to start reception of a second incoming data byte before software has finished reading the previous data byte. The UART has an associated Serial Control Register (SCON) and a Serial Data Buffer (SBUF) in the SFRs. The single SBUF location provides access to both transmit and receive registers. Reads access the Receive register and writes access the Transmit register automatically. The UART is capable of generating interrupts if enabled. The UART has two sources of interrupts: a Transmit Interrupt flag, TI (SCON.1) set when transmission of a data byte is complete, and a Receive Interrupt flag, RI (SCON.0) set when reception of a data byte is complete. The UART interrupt flags are not cleared by hardware when the CPU vectors to the interrupt service routine. They must be cleared manually by software. This allows software to determine the cause of the UART interrupt (transmit complete or receive complete).
Figure 16.1. UART Block Diagram
SFR Bus
PCON
S M O D Write to SBUF TB8
SCON
SSSRTRTR MMMEB B I I 012N88
T2CON
R C L K T C L K
SET
D
CLR
Q
SBUF
TX
Crossbar
Zero Detector
Baud Rate Generation Logic
Start Timer 1 Overflow 1 0 0 1 SMOD TCLK SM0, SM1 {MODE} 0 Timer 2 Overflow 00 00 01 10 11 Stop Bit Gen. Shift Data
2
Tx Control
Tx Clock TI Serial Port Interrupt RI Rx Clock Rx IRQ Enable MSB Load SBUF Shift 0x1FF Tx IRQ Send
16
REN
RB8
16
1 RCLK
01 10 11
Rx Control
Start
32 64
SYSCLK
1 0
Port I/O
Bit Detector Input Shift Register (9 bits)
Shift Load SBUF
SMOD
12
SBUF
Read SBUF
SFR Bus
RX
Crossbar
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16.1. UART Operational Modes
PRELIMINARY
The UART provides four operating modes (one synchronous and three asynchronous) selected by setting configuration bits in the SCON register. These four modes offer different baud rates and communication protocols. The four modes are summarized in Table 16.1 below. Detailed descriptions follow.
Table 16.1. UART Modes
Mode 0 1 2 3 Synchronization Synchronous Asynchronous Asynchronous Asynchronous Baud Clock SYSCLK/12 Timer 1 or Timer 2 Overflow SYSCLK/32 or SYSCLK/64 Timer 1 or Timer 2 Overflow Data Bits 8 8 9 9 Start/Stop Bits None 1 Start, 1 Stop 1 Start, 1 Stop 1 Start, 1 Stop
16.1.1. Mode 0: Synchronous Mode
Mode 0 provides synchronous, half-duplex communication. Serial data is transmitted and received on the RX pin. The TX pin provides the shift clock for both transmit and receive. The MCU must be the master since it generates the shift clock for transmission in both directions (see the interconnect diagram in Figure 16.2). Eight data bits are transmitted/received, LSB first (see the timing diagram in Figure 16.3). Data transmission begins when an instruction writes a data byte to the SBUF register. The TI Transmit Interrupt Flag (SCON.1) is set at the end of the eighth bit time. Data reception begins when the REN Receive Enable bit (SCON.4) is set to logic 1 and the RI Receive Interrupt Flag (SCON.0) is cleared. One cycle after the eighth bit is shifted in, the RI flag is set and reception stops until software clears the RI bit. An interrupt will occur if enabled when either TI or RI is set. The Mode 0 baud rate is the system clock frequency divided by twelve. RX is forced to open-drain in mode 0, and an external pull-up will typically be required.
Figure 16.2. UART Mode 0 Interconnect
TX CLK DATA
C8051Fxxx
RX
Shift Reg.
8 Extra Outputs
Figure 16.3. UART Mode 0 Timing Diagram
MODE 0 TRANSMIT RX (data out) TX (clk out)
D0 D1 D2 D3 D4 D5 D6 D7
MODE 0 RECEIVE RX (data in) TX (clk out)
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16.1.2. Mode 1: 8-Bit UART, Variable Baud Rate
C8051F018 C8051F019
Mode 1 provides standard asynchronous, full duplex communication using a total of 10 bits per data byte: one start bit, eight data bits (LSB first), and one stop bit. Data are transmitted from the TX pin and received at the RX pin. On receive, the eight data bits are stored in SBUF and the stop bit goes into RB8 (SCON.2). Data transmission begins when an instruction writes a data byte to the SBUF register. The TI Transmit Interrupt Flag (SCON.1) is set at the end of the transmission (the beginning of the stop-bit time). Data reception can begin any time after the REN Receive Enable bit (SCON.4) is set to logic 1. After the stop bit is received, the data byte will be loaded into the SBUF receive register if the following conditions are met: RI must be logic 0, and if SM2 is logic 1, the stop bit must be logic 1. If these conditions are met, the eight bits of data are stored in SBUF, the stop bit is stored in RB8 and the RI flag is set. If these conditions are not met, SBUF and RB8 will not be loaded and the RI flag will not be set. An interrupt will occur if enabled when either TI or RI is set. The baud rate generated in Mode 1 is a function of timer overflow. The UART can use either Timer 1 or Timer 2 operating in auto-reload mode to generate the baud rate. On each timer overflow event (a rollover from all ones - 0xFF for Timer 1, 0xFFFF for Timer 2 - to zero) a clock is sent to the baud rate circuit. This clock is divided by 16 to generate the baud rate. Timer 1 should be configured for 8-bit Counter/Timer with Auto-Reload mode when used as a baud rate generator. The combination of system clock frequency and the reload value stored in TH1 determine the baud rate as follows: Mode 1 Baud Rate = (2SMOD / 32) * (SYSCLK)/(12(T1M - 1) * (256 - TH1)). The SMOD bit (PCON.7) selects whether or not to divide the Timer 1 overflow rate by two. On reset, the SMOD bit is logic 0, thus selecting the lower speed baud rate by default. Selecting the timebase used by Timer 1 allows further control of baud rate generation. Using the system clock divided by one (setting T1M in CKCON) changes the twelve in the denominator of the equation above to a one. To use Timer 2 for baud rate generation, configure the timer Baud Rate Generator mode and set RCLK and/or TCLK to logic 1. Setting RCLK and/or TCLK automatically disables Timer 2 interrupts and configures Timer 2 to use the system clock divided by two as its timebase. If a different timebase is required, setting the C/T2 bit to logic 1 will allow the timebase to be derived from a clock supplied to the external input pin T2. The combination of clock frequency and the reload value stored in capture registers determine the baud rate as follows: Mode 1 Baud Rate = SYSCLK / [32 * (65536 - [RCAP2H:RCAP2L]) ], where [RCAP2H:RCAP2L] is the 16-bit value held in the capture registers.
Figure 16.4. UART Mode 1 Timing Diagram
MARK SPACE BIT TIMES START BIT D0 D1 D2 D3 D4 D5 D6 D7 STOP BIT
BIT SAMPLING
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Figure 16.5. UART Modes 1, 2, and 3 Interconnect Diagram
RS-232 LEVEL XLTR TX RX
RS-232
C8051Fxxx
OR
TX TX
MCU
RX RX
C8051Fxxx
16.1.3. Mode 2: 9-Bit UART, Fixed Baud Rate
Mode 2 provides asynchronous, full-duplex communication using a total of eleven bits per data byte: a start bit, 8 data bits (LSB first), a programmable ninth data bit, and a stop bit. On transmit, the ninth data bit is determined by the value in TB8 (SCON.3). It can be assigned the value of the parity flag P in the PSW or used in multiprocessor communications. On receive, the ninth data bit goes into RB8 (SCON.2) and the stop bit is ignored. Data transmission begins when an instruction writes a data byte to the SBUF register. The TI Transmit Interrupt Flag (SCON.1) is set at the end of the transmission (the beginning of the stop-bit time). Data reception can begin any time after the REN Receive Enable bit (SCON.4) is set to logic 1. After the stop bit is received, the data byte will be loaded into the SBUF receive register if the following conditions are met: RI must be logic 0, and if SM2 is logic 1, the 9th bit must be logic 1. If these conditions are met, the eight bits of data are stored in SBUF, the ninth bit is stored in RB8 and the RI flag is set. If these conditions are not met, SBUF and RB8 will not be loaded and the RI flag will not be set. An interrupt will occur if enabled when either TI or RI are set. The baud rate in Mode 2 is a direct function of the system clock frequency as follows: Mode 2 Baud Rate = 2SMOD * (SYSCLK / 64). The SMOD bit (PCON.7) selects whether to divide SYSCLK by 32 or 64. In the formula, 2 is raised to the power SMOD, resulting in a baud rate of either 1/32 or 1/64 of the system clock frequency. On reset, the SMOD bit is logic 0, thus selecting the lower speed baud rate by default.
Figure 16.6. UART Modes 2 and 3 Timing Diagram
MARK SPACE BIT TIMES START BIT D0 D1 D2 D3 D4 D5 D6 D7 D8 STOP BIT
BIT SAMPLING
16.1.4. Mode 3: 9-Bit UART, Variable Baud Rate
Mode 3 is the same as Mode 2 in all respects except the baud rate is variable. The baud rate is determined in the same manner as for Mode 1. Mode 3 operation transmits 11 bits: a start bit, 8 data bits (LSB first), a programmable ninth data bit, and a stop bit. Timer 1 or Timer 2 overflows generate the baud rate just as with Mode 1. In summary, Mode 3 transmits using the same protocol as Mode 2 but with Mode 1 baud rate generation.
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16.2. Multiprocessor Communications
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Modes 2 and 3 support multiprocessor communication between a master processor and one or more slave processors by special use of the ninth data bit. When a master processor wants to transmit to one or more slaves, it first sends an address byte to select the target(s). An address byte differs from a data byte in that its ninth bit is logic 1; in a data byte, the ninth bit is always set to logic 0. Setting the SM2 bit (SCON.5) of a slave processor configures its UART such that when a stop bit is received, the UART will generate an interrupt only if the ninth bit is logic one (RB8 = 1) signifying an address byte has been received. In the UART's interrupt handler, software will compare the received address with the slave's own assigned 8-bit address. If the addresses match, the slave will clear its SM2 bit to enable interrupts on the reception of the following data byte(s). Slaves that weren't addressed leave their SM2 bits set and do not generate interrupts on the reception of the following data bytes, thereby ignoring the data. Once the entire message is received, the addressed slave resets its SM2 bit to ignore all transmissions until it receives the next address byte. Multiple addresses can be assigned to a single slave and/or a single address can be assigned to multiple slaves, thereby enabling "broadcast" transmissions to more than one slave simultaneously. The master processor can be configured to receive all transmissions or a protocol can be implemented such that the master/slave role is temporarily reversed to enable half-duplex transmission between the original master and slave(s).
Figure 16.7. UART Multi-Processor Mode Interconnect Diagram
Master Device
RX TX
Slave Device
RX TX
Slave Device
RX TX
Slave Device
RX TX
VDD
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Oscillator Frequency (MHz) 24.0 23.592 22.1184 18.432 16.5888 14.7456 12.9024 11.0592 9.216 7.3728 5.5296 3.6864 1.8432 24.576 25.0 25.0 24.576 24.0 23.592 22.1184 18.432 16.5888 14.7456 12.9024 11.0592 9.216 7.3728 5.5296 3.6864 1.8432
PRELIMINARY
Divide Factor 208 205 192 160 144 128 112 96 80 64 48 32 16 320 434 868 848 833 819 768 640 576 512 448 384 320 256 192 128 64 Timer 1 Load Value* 0xF3 0xF3 0xF4 0xF6 0xF7 0xF8 0xF9 0xFA 0xFB 0xFC 0xFD 0xFE 0xFF 0xEC 0xE5 0xCA 0xCB 0xCC 0xCD 0xD0 0xD8 0xDC 0xE0 0xE4 0xE8 0xEC 0xF0 0xF4 0xF8 0xFC Resulting Baud Rate** 115200 (115384) 115200 (113423) 115200 115200 115200 115200 115200 115200 115200 115200 115200 115200 115200 76800 57600 (57870) 28800 28800 (28921) 28800 (28846) 28800 (28911) 28800 28800 28800 28800 28800 28800 28800 28800 28800 28800 28800
Table 16.2. Oscillator Frequencies for Standard Baud Rates
* Assumes SMOD=1 and T1M=1. ** Numbers in parenthesis show the actual baud rate.
Figure 16.8. SBUF: Serial (UART) Data Buffer Register
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0x99
Bits7-0: SBUF.[7:0]: Serial Data Buffer Bits 7-0 (MSB-LSB) This is actually two registers; a transmit and a receive buffer register. When data is moved to SBUF, it goes to the transmit buffer and is held for serial transmission. Moving a byte to SBUF is what initiates the transmission. When data is moved from SBUF, it comes from the receive buffer.
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Figure 16.9. SCON: Serial Port Control Register
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
SM0
Bit7
SM1
Bit6
SM2
Bit5
REN
Bit4
TB8
Bit3
RB8
Bit2
TI
Bit1
RI
Bit0
(bit addressable)
00000000
SFR Address:
0x98
Bits7-6: SM0-SM1: Serial Port Operation Mode. These bits select the Serial Port Operation Mode. SM0 SM1 Mode 0 0 Mode 0: Synchronous Mode 0 1 Mode 1: 8-Bit UART, Variable Baud Rate 1 0 Mode 2: 9-Bit UART, Fixed Baud Rate 1 1 Mode 3: 9-Bit UART, Variable Baud Rate Bit5: SM2: Multiprocessor Communication Enable. The function of this bit is dependent on the Serial Port Operation Mode. Mode 0: No effect Mode 1: Checks for valid stop bit. 0: Logic level of stop bit is ignored. 1: RI will only be activated if stop bit is logic level 1. Mode 2 and 3: Multiprocessor Communications Enable. 0: Logic level of ninth bit is ignored. 1: RI is set and an interrupt is generated only when the ninth bit is logic 1. REN: Receive Enable. This bit enables/disables the UART receiver. 0: UART reception disabled. 1: UART reception enabled. TB8: Ninth Transmission Bit. The logic level of this bit will be assigned to the ninth transmission bit in Modes 2 and 3. It is not used in Modes 0 and 1. Set or cleared by software as required. RB8: Ninth Receive Bit. The bit is assigned the logic level of the ninth bit received in Modes 2 and 3. In Mode 1, if SM2 is logic 0, RB8 is assigned the logic level of the received stop bit. RB8 is not used in Mode 0. TI: Transmit Interrupt Flag. Set by hardware when a byte of data has been transmitted by the UART (after the 8th bit in Mode 0, or at the beginning of the stop bit in other modes). When the UART interrupt is enabled, setting this bit causes the CPU to vector to the UART interrupt service routine. This bit must be cleared manually by software RI: Receive Interrupt Flag. Set by hardware when a byte of data has been received by the UART (after the 8th bit in Mode 0, or after the stop bit in other modes - see SM2 bit for exception). When the UART interrupt is enabled, setting this bit causes the CPU to vector to the UART interrupt service routine. This bit must be cleared manually by software.
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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17. TIMERS
PRELIMINARY
Each MCU implements four counter/timers: three are 16-bit counter/timers compatible with those found in the standard 8051, and one is a 16-bit timer for use with the ADC, SMBus, or for general purpose use. These can be used to measure time intervals, count external events and generate periodic interrupt requests. Timer 0 and Timer 1 are nearly identical and have four primary modes of operation. Timer 2 offers additional capabilities not available in Timers 0 and 1. Timer 3 is similar to Timer 2, but without the capture or Baud Rate Generator modes. Timer 0 and Timer 1: 13-bit counter/timer 16-bit counter/timer 8-bit counter/timer with auto-reload Two 8-bit counter/timers (Timer 0 only) Timer 2: 16-bit counter/timer with auto-reload 16-bit counter/timer with capture Baud rate generator Timer 3: 16-bit timer with auto-reload
When functioning as a timer, the counter/timer registers are incremented on each clock tick. Clock ticks are derived from the system clock divided by either one or twelve as specified by the Timer Clock Select bits (T2M-T0M) in CKCON. The twelve-clocks-per-tick option provides compatibility with the older generation of the 8051 family. Applications that require a faster timer can use the one-clock-per-tick option. When functioning as a counter, a counter/timer register is incremented on each high-to-low transition at the selected input pin for T0, T1, or T2. Events with a frequency of up to one-fourth the system clock's frequency can be counted. The input signal need not be periodic, but it should be held at a given level for at least two full system clock cycles to ensure the level is sampled.
17.1.
Timer 0 and Timer 1
Timer 0 and Timer 1 are accessed and controlled through SFRs. Each counter/timer is implemented as a 16-bit register accessed as two separate bytes: a low byte (TL0 or TL1) and a high byte (TH0 or TH1). The Counter/Timer Control (TCON) register is used to enable Timer 0 and Timer 1 as well as indicate their status. Both counter/timers operate in one of four primary modes selected by setting the Mode Select bits M1-M0 in the Counter/Timer Mode (TMOD) register. Each timer can be configured independently. Following is a detailed description of each operating mode.
17.1.1. Mode 0: 13-bit Counter/Timer
Timer 0 and Timer 1 operate as a 13-bit counter/timer in Mode 0. The following describes the configuration and operation of Timer 0. However, both timers operate identically and Timer 1 is configured in the same manner as described for Timer 0. The TH0 register holds the eight MSBs of the 13-bit counter/timer. TL0 holds the five LSBs in bit positions TL0.4TL0.0. The three upper bits of TL0 (TL0.7-TL0.5) are indeterminate and should be masked out or ignored when reading. As the 13-bit timer register increments and overflows from 0x1FFF (all ones) to 0x0000, the timer overflow flag TF0 (TCON.5) is set and an interrupt will occur if enabled. The C/T0 bit (TMOD.2) selects the counter/timer's clock source. Clearing C/T selects the system clock as the input for the timer. When C/T0 is set to logic 1, high-to-low transitions at the selected input pin increment the timer register. (Refer to Port I/O Section 13.1 for information on selecting and configuring external I/O pins.)
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Setting the TR0 bit (TCON.4) enables the timer when either GATE0 (TMOD.3) is 0 or the input signal /INT0 is logic-level one. Setting GATE0 to logic 1 allows the timer to be controlled by the external input signal /INT0, facilitating pulse width measurements. TR0 GATE0 0 X 1 0 1 1 1 1 X = Don't Care /INT0 X X 0 1 Counter/Timer Disabled Enabled Disabled Enabled
Setting TR0 does not reset the timer register. The timer register should be initialized to the desired value before enabling the timer. TL1 and TH1 form the 13-bit register for Timer 1 in the same manner as described above for TL0 and TH0. Timer 1 is configured and controlled using the relevant TCON and TMOD bits just as with Timer 0.
Figure 17.1. T0 Mode 0 Block Diagram
CKCON
TTT 210 MMM
TMOD
G A T E 1
C / T 1
TT 11 MM 10
G A T E 0
C / T 0
TT 00 MM 10
12 SYSCLK
0 1 0 1
T0
Crossbar TR0 GATE0
TCLK
/INT0
Crossbar
17.1.2. Mode 1: 16-bit Counter/Timer
Mode 1 operation is the same as Mode 0, except that the counter/timer registers use all 16 bits. The counter/timers are enabled and configured in Mode 1 in the same manner as for Mode 0.
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TCON
TL0 (5 bits)
TH0 (8 bits)
TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0
Interrupt
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17.1.3. Mode 2: 8-bit Counter/Timer with Auto-Reload
Mode 2 configures Timer 0 and Timer 1 to operate as 8-bit counter/timers with automatic reload of the start value. The TL0 holds the count and TH0 holds the reload value. When the count in TL0 overflows from all ones to 0x00, the timer overflow flag TF0 (TCON.5) is set and the counter in TL0 is reloaded from TH0. If enabled, an interrupt will occur when the TF0 flag is set. The reload value in TH0 is not changed. TL0 must be initialized to the desired value before enabling the timer for the first count to be correct. When in Mode 2, Timer 1 operates identically to Timer 0. Both counter/timers are enabled and configured in Mode 2 in the same manner as Mode 0.
Figure 17.2. T0 Mode 2 Block Diagram
CKCON
TTT 210 MMM
G A T E 1
TMOD
C / T 1 TT 11 MM 10
G A T E 0
C / T 0
TT 00 MM 10
12 SYSCLK
0 1 0 1
T0
Crossbar TR0 GATE0
TCLK
TL0 (8 bits) TCON
TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0
Interrupt
/INT0
Crossbar
TH0 (8 bits)
Reload
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17.1.4. Mode 3: Two 8-bit Counter/Timers (Timer 0 Only)
C8051F018 C8051F019
Timer 0 and Timer 1 behave differently in Mode 3. Timer 0 is configured as two separate 8-bit counter/timers held in TL0 and TH0. The counter/timer in TL0 is controlled using the Timer 0 control/status bits in TCON and TMOD: TR0, C/T0, GATE0 and TF0. It can use either the system clock or an external input signal as its timebase. The TH0 register is restricted to a timer function sourced by the system clock. TH0 is enabled using the Timer 1 run control bit TR1. TH0 sets the Timer 1 overflow flag TF1 on overflow and thus controls the Timer 1 interrupt. Timer 1 is inactive in Mode 3, so with Timer 0 in Mode 3, Timer 1 can be turned off and on by switching it into and out of its Mode 3. When Timer 0 is in Mode 3, Timer 1 can be operated in Modes 0, 1 or 2, but cannot be clocked by external signals nor set the TF1 flag and generate an interrupt. However, the Timer 1 overflow can be used for baud rate generation. Refer to Section 16 (UART) for information on configuring Timer 1 for baud rate generation.
Figure 17.3. T0 Mode 3 Block Diagram
CKCON
TTT 210 MMM
G A T E 1
TMOD
C / T 1 TT 11 MM 10
G A T E 0
C / T 0
TT 00 MM 10
TR1 12 SYSCLK
1 0 1 0
TH0 (8 bits) TCON C/T0
T0
Crossbar
TL0 (8 bits)
TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0
Interrupt Interrupt
TR0 GATE0 /INT0
Crossbar
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Figure 17.4. TCON: Timer Control Register
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
TF1
Bit7
TR1
Bit6
TF0
Bit5
TR0
Bit4
IE1
Bit3
IT1
Bit2
IE0
Bit1
IT0
Bit0
(bit addressable)
00000000
SFR Address:
0x88
Bit7:
TF1: Timer 1 Overflow Flag. Set by hardware when Timer 1 overflows. This flag can be cleared by software but is automatically cleared when the CPU vectors to the Timer 1 interrupt service routine. 0: No Timer 1 overflow detected. 1: Timer 1 has overflowed. TR1: Timer 1 Run Control. 0: Timer 1 disabled. 1: Timer 1 enabled. TF0: Timer 0 Overflow Flag. Set by hardware when Timer 0 overflows. This flag can be cleared by software but is automatically cleared when the CPU vectors to the Timer 0 interrupt service routine. 0: No Timer 0 overflow detected. 1: Timer 0 has overflowed. TR0: Timer 0 Run Control. 0: Timer 0 disabled. 1: Timer 0 enabled. IE1: External Interrupt 1. This flag is set by hardware when an edge/level of type defined by IT1 is detected. It can be cleared by software but is automatically cleared when the CPU vectors to the External Interrupt 1 service routine if IT1 = 1. This flag is the inverse of the /INT1 input signal's logic level when IT1 = 0. IT1: Interrupt 1 Type Select. This bit selects whether the configured /INT1 signal will detect falling edge or active-low level-sensitive interrupts. 0: /INT1 is level triggered. 1: /INT1 is edge triggered. IE0: External Interrupt 0. This flag is set by hardware when an edge/level of type defined by IT0 is detected. It can be cleared by software but is automatically cleared when the CPU vectors to the External Interrupt 0 service routine if IT0 = 1. This flag is the inverse of the /INT0 input signal's logic level when IT0 = 0. IT0: Interrupt 0 Type Select. This bit selects whether the configured /INT0 signal will detect falling edge or active-low level-sensitive interrupts. 0: /INT0 is level triggered. 1: /INT0 is edge triggered.
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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Figure 17.5. TMOD: Timer Mode Register
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
GATE1
Bit7
C/T1
Bit6
T1M1
Bit5
T1M0
Bit4
GATE0
Bit3
C/T0
Bit2
T0M1
Bit1
T0M0
Bit0
00000000
SFR Address:
0x89
Bit7:
GATE1: Timer 1 Gate Control. 0: Timer 1 enabled when TR1 = 1 irrespective of /INT1 logic level. 1: Timer 1 enabled only when TR1 = 1 AND /INT1 = logic level one. C/T1: Counter/Timer 1 Select. 0: Timer Function: Timer 1 incremented by clock defined by T1M bit (CKCON.4). 1: Counter Function: Timer 1 incremented by high-to-low transitions on external input pin (T1).
Bit6:
Bits5-4: T1M1-T1M0: Timer 1 Mode Select. These bits select the Timer 1 operation mode. T1M1 0 0 1 1 Bit3: T1M0 0 1 0 1 Mode Mode 0: 13-bit counter/timer Mode 1: 16-bit counter/timer Mode 2: 8-bit counter/timer with auto-reload Mode 3: Timer 1 Inactive/stopped
GATE0: Timer 0 Gate Control. 0: Timer 0 enabled when TR0 = 1 irrespective of /INT0 logic level. 1: Timer 0 enabled only when TR0 = 1 AND /INT0 = logic level one. C/T0: Counter/Timer Select. 0: Timer Function: Timer 0 incremented by clock defined by T0M bit (CKCON.3). 1: Counter Function: Timer 0 incremented by high-to-low transitions on external input pin (T0).
Bit2:
Bits1-0: T0M1-T0M0: Timer 0 Mode Select. These bits select the Timer 0 operation mode. T0M1 0 0 1 1 T0M0 0 1 0 1 Mode Mode 0: 13-bit counter/timer Mode 1: 16-bit counter/timer Mode 2: 8-bit counter/timer with auto-reload Mode 3: Two 8-bit counter/timers
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Figure 17.6. CKCON: Clock Control Register
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
Bit7
Bit6
T2M
Bit5
T1M
Bit4
T0M
Bit3
Reserved
Bit2
Reserved
Bit1
Reserved
Bit0
00000000
SFR Address:
0x8E
Bits7-6: UNUSED. Read = 00b, Write = don't care. Bit5: T2M: Timer 2 Clock Select. This bit controls the division of the system clock supplied to Timer 2. This bit is ignored when the timer is in baud rate generator mode or counter mode (i.e. C/T2 = 1). 0: Timer 2 uses the system clock divided by 12. 1: Timer 2 uses the system clock. T1M: Timer 1 Clock Select. This bit controls the division of the system clock supplied to Timer 1. 0: Timer 1 uses the system clock divided by 12. 1: Timer 1 uses the system clock. T0M: Timer 0 Clock Select. This bit controls the division of the system clock supplied to Counter/Timer 0. 0: Counter/Timer uses the system clock divided by 12. 1: Counter/Timer uses the system clock.
Bit4:
Bit3:
Bits2-0: Reserved. Read = 000b, Must Write = 000.
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Figure 17.7. TL0: Timer 0 Low Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1
C8051F018 C8051F019
R/W Bit0
Reset Value
00000000
SFR Address:
0x8A
Bits 7-0: TL0: Timer 0 Low Byte. The TL0 register is the low byte of the 16-bit Timer 0.
Figure 17.8. TL1: Timer 1 Low Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0x8B
Bits 7-0: TL1: Timer 1 Low Byte. The TL1 register is the low byte of the 16-bit Timer 1.
Figure 17.9. TH0: Timer 0 High Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0x8C
Bits 7-0: TH0: Timer 0 High Byte. The TH0 register is the high byte of the 16-bit Timer 0.
Figure 17.10. TH1: Timer 1 High Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0x8D
Bits 7-0: TH1: Timer 1 High Byte. The TH1 register is the high byte of the 16-bit Timer 1.
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17.2. Timer 2
PRELIMINARY
Timer 2 is a 16-bit counter/timer formed by the two 8-bit SFRs: TL2 (low byte) and TH2 (high byte). As with Timers 0 and 1, Timer 2 can use either the system clock or transitions on an external input pin as its clock source. The Counter/Timer Select bit C/T2 bit (T2CON.1) selects the clock source for Timer 2. Clearing C/T2 selects the system clock as the input for the timer (divided by either one or twelve as specified by the Timer Clock Select bit T2M in CKCON). When C/T2 is set to 1, high-to-low transitions at the T2 input pin increment the counter/timer register. (Refer to Section 12 for information on selecting and configuring external I/O pins.) Timer 2 can also be used to start an ADC Data Conversion. Timer 2 offers capabilities not found in Timer 0 and Timer 1. It operates in one of three modes: 16-bit Counter/Timer with Capture, 16-bit Counter/Timer with Auto-Reload or Baud Rate Generator Mode. Timer 2's operating mode is selected by setting configuration bits in the Timer 2 Control (T2CON) register. Below is a summary of the Timer 2 operating modes and the T2CON bits used to configure the counter/timer. Detailed descriptions of each mode follow. RCLK 0 0 0 1 1 X TCLK 0 0 1 0 1 X CP/RL2 1 0 X X X X TR2 1 1 1 1 1 0 Mode 16-bit Counter/Timer with Capture 16-bit Counter/Timer with Auto-Reload Baud Rate Generator for TX Baud Rate Generator for RX Baud Rate Generator for TX and RX Off
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17.2.1. Mode 0: 16-bit Counter/Timer with Capture
C8051F018 C8051F019
In this mode, Timer 2 operates as a 16-bit counter/timer with capture facility. A high-to-low transition on the T2EX input pin causes the 16-bit value in Timer 2 (TH2, TL2) to be loaded into the capture registers (RCAP2H, RCAP2L). Timer 2 can use either SYSCLK, SYSCLK divided by 12, or high-to-low transitions on the external T2 pin as its clock source when operating in Counter/Timer with Capture mode. Clearing the C/T2 bit (T2CON.1) selects the system clock as the input for the timer (divided by one or twelve as specified by the Timer Clock Select bit T2M in CKCON). When C/T2 is set to logic 1, a high-to-low transition at the T2 input pin increments the counter/timer register. As the 16-bit counter/timer register increments and overflows from 0xFFFF to 0x0000, the TF2 timer overflow flag (T2CON.7) is set and an interrupt will occur if the interrupt is enabled. Counter/Timer with Capture mode is selected by setting the Capture/Reload Select bit CP/RL2 (T2CON.0) and the Timer 2 Run Control bit TR2 (T2CON.2) to logic 1. The Timer 2 External Enable EXEN2 (T2CON.3) must also be set to logic 1 to enable a capture. If EXEN2 is cleared, transitions on T2EX will be ignored.
Figure 17.11. T2 Mode 0 Block Diagram
CKCON
TTT 210 MMM
12 SYSCLK
0 1 0 1 TCLK
T2
Crossbar
TL2
TH2 T2CON
TR2
EXEN2 T2EX Crossbar
Capture
RCAP2L
RCAP2H
CP/RL2 C/T2 TR2 EXEN2 TCLK RCLK EXF2 TF2
Interrupt
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17.2.2. Mode 1: 16-bit Counter/Timer with Auto-Reload
The Counter/Timer with Auto-Reload mode sets the TF2 timer overflow flag when the counter/timer register overflows from 0xFFFF to 0x0000. An interrupt is generated if enabled. On overflow, the 16-bit value held in the two capture registers (RCAP2H, RCAP2L) is automatically loaded into the counter/timer register and the timer is restarted. Counter/Timer with Auto-Reload mode is selected by clearing the CP/RL2 bit. Setting TR2 to logic 1 enables and starts the timer. Timer 2 can use either the system clock or transitions on an external input pin as its clock source, as specified by the C/T2 bit. If EXEN2 is set to logic 1, a high-to-low transition on T2EX will also cause Timer 2 to be reloaded. If EXEN2 is cleared, transitions on T2EX will be ignored.
Figure 17.12. T2 Mode 1 Block Diagram
CKCON
TTT 210 MMM
12 SYSCLK
0 1 0
T2
Crossbar TR2 EXEN2
1
TCLK
TL2
TH2 T2CON
Reload
T2EX
Crossbar
RCAP2L
RCAP2H
CP/RL2 C/T2 TR2 EXEN2 TCLK RCLK EXF2 TF2
Interrupt
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17.2.3. Mode 2: Baud Rate Generator
C8051F018 C8051F019
Timer 2 can be used as a baud rate generator for the serial port (UART) when the UART is operated in modes 1 or 3 (refer to Section 16.1 for more information on UART operational modes). In Baud Rate Generator mode, Timer 2 works similarly to the auto-reload mode. On overflow, the 16-bit value held in the two capture registers (RCAP2H, RCAP2L) is automatically loaded into the counter/timer register. However, the TF2 overflow flag is not set and no interrupt is generated. Instead, the overflow event is used as the input to the UART's shift clock. Timer 2 overflows can be used to generate baud rates for transmit and/or receive independently. The Baud Rate Generator mode is selected by setting RCLK (T2CON.5) and/or TCLK (T2CON.4) to logic one. When RCLK or TCLK is set to logic 1, Timer 2 operates in the auto-reload mode regardless of the state of the CP/RL2 bit. The baud rate for the UART, when operating in mode 1 or 3, is determined by the Timer 2 overflow rate: Baud Rate = Timer 2 Overflow Rate / 16. Note, in all other modes, the timebase for the timer is the system clock divided by one or twelve as selected by the T2M bit in CKCON. However, in Baud Rate Generator mode, the timebase is the system clock divided by two. No other divisor selection is possible. If a different time base is required, setting the C/T2 bit to logic 1 will allow the timebase to be derived from the external input pin T2. In this case, the baud rate for the UART is calculated as: Baud Rate = FCLK / [32 * (65536 - [RCAP2H:RCAP2L]) ] Where FCLK is the frequency of the signal supplied to T2 and [RCAP2H:RCAP2L] is the 16-bit value held in the capture registers. As explained above, in Baud Rate Generator mode, Timer 2 does not set the TF2 overflow flag and therefore cannot generate an interrupt. However, if EXEN2 is set to logic 1, a high-to-low transition on the T2EX input pin will set the EXF2 flag and a Timer 2 interrupt will occur if enabled. Therefore, the T2EX input may be used as an additional external interrupt source.
Figure 17.13. T2 Mode 2 Block Diagram
SYSCLK 2
0 1
C/T2
Timer 2 Overflow
T2
Crossbar TR2
TCLK
TL2
TH2
1
PCON
S M O D
0 1
Reload
16
0
RX Clock
2 Timer 1 Overflow
SI GG TD FF OL 10 PE
RCAP2L
RCAP2H
RCLK
1
16
0
TX Clock
EXEN2 T2EX Crossbar
CP/RL2 C/T2 TR2 EXEN2 TCLK RCLK EXF2 TF2
TCLK
T2CON
Interrupt
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Figure 17.14. T2CON: Timer 2 Control Register
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
TF2
Bit7
EXF2
Bit6
RCLK
Bit5
TCLK
Bit4
EXEN2
Bit3
TR2
Bit2
C/T2
Bit1
CP/RL2
Bit0
(bit addressable)
00000000
SFR Address:
0xC8
Bit7:
TF2: Timer 2 Overflow Flag. Set by hardware when Timer 2 overflows from 0xFFFF to 0x0000 or reload value. When the Timer 2 interrupt is enabled, setting this bit causes the CPU to vector to the Timer 2 interrupt service routine. This bit is not automatically cleared by hardware and must be cleared by software. TF2 will not be set when RCLK and/or TCLK are logic 1. EXF2: Timer 2 External Flag. Set by hardware when either a capture or reload is caused by a high-to-low transition on the T2EX input pin and EXEN2 is logic 1. When the Timer 2 interrupt is enabled, setting this bit causes the CPU to vector to the Timer 2 Interrupt service routine. This bit is not automatically cleared by hardware and must be cleared by software. RCLK: Receive Clock Flag. Selects which timer is used for the UART's receive clock in modes 1 or 3. 0: Timer 1 overflows used for receive clock. 1: Timer 2 overflows used for receive clock. TCLK: Transmit Clock Flag. Selects which timer is used for the UART's transmit clock in modes 1 or 3. 0: Timer 1 overflows used for transmit clock. 1: Timer 2 overflows used for transmit clock. EXEN2: Timer 2 External Enable. Enables high-to-low transitions on T2EX to trigger captures or reloads when Timer 2 is not operating in Baud Rate Generator mode. 0: High-to-low transitions on T2EX ignored. 1: High-to-low transitions on T2EX cause a capture or reload. TR2: Timer 2 Run Control. This bit enables/disables Timer 2. 0: Timer 2 disabled. 1: Timer 2 enabled. C/T2: Counter/Timer Select. 0: Timer Function: Timer 2 incremented by clock defined by T2M (CKCON.5). 1: Counter Function: Timer 2 incremented by high-to-low transitions on external input pin (T2). CP/RL2: Capture/Reload Select. This bit selects whether Timer 2 functions in capture or auto-reload mode. EXEN2 must be logic 1 for high-to-low transitions on T2EX to be recognized and used to trigger captures or reloads. If RCLK or TCLK is set, this bit is ignored and Timer 2 will function in autoreload mode. 0: Auto-reload on Timer 2 overflow or high-to-low transition at T2EX (EXEN2 = 1). 1: Capture on high-to-low transition at T2EX (EXEN2 = 1).
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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Figure 17.15. RCAP2L: Timer 2 Capture Register Low Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xCA
Bits 7-0: RCAP2L: Timer 2 Capture Register Low Byte. The RCAP2L register captures the low byte of Timer 2 when Timer 2 is configured in capture mode. When Timer 2 is configured in auto-reload mode, it holds the low byte of the reload value.
Figure 17.16. RCAP2H: Timer 2 Capture Register High Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value 00000000
SFR Address:
0xCB
Bits 7-0: RCAP2H: Timer 2 Capture Register High Byte. The RCAP2H register captures the high byte of Timer 2 when Timer 2 is configured in capture mode. When Timer 2 is configured in auto-reload mode, it holds the high byte of the reload value.
Figure 17.17. TL2: Timer 2 Low Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xCC
Bits 7-0: TL2: Timer 2 Low Byte. The TL2 register contains the low byte of the 16-bit Timer 2.
Figure 17.18. TH2: Timer 2 High Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xCD
Bits 7-0: TH2: Timer 2 High Byte. The TH2 register contains the high byte of the 16-bit Timer 2.
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17.3. Timer 3
PRELIMINARY
Timer 3 is a 16-bit timer formed by the two 8-bit SFRs, TMR3L (low byte) and TMR3H (high byte). The input for Timer 3 is the system clock (divided by either one or twelve as specified by the Timer 3 Clock Select bit T3M in the Timer 3 Control Register TMR3CN). Timer 3 is always configured as an auto-reload timer, with the reload value held in the TMR3RLL (low byte) and TMR3RLH (high byte) registers. Timer 3 can be used to start an ADC Data Conversion, for SMBus timing (see Section 14.5), or as a general-purpose timer. Timer 3 does not have a counter mode.
Figure 17.19. Timer 3 Block Diagram
12 SYSCLK
1 TCLK 0
T3M
(to ADC)
TMR3L
TMR3H TMR3CN
TF3
Interrupt
TR3
(from SMBus) TOE Reload
TR3 T3M
SCL
Crossbar
TMR3RLL TMR3RLH
Figure 17.20. TMR3CN: Timer 3 Control Register
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
TF3
Bit7
Bit6
Bit5
Bit4
Bit3
TR3
Bit2
T3M
Bit1
Bit0
00000000
SFR Address:
0x91
Bit7:
TF3: Timer3 Overflow Flag. Set by hardware when Timer 3 overflows from 0xFFFF to 0x0000. When the Timer 3 interrupt is enabled, setting this bit causes the CPU to vector to the Timer 3 Interrupt service routine. This bit is not automatically cleared by hardware and must be cleared by software.
Bits6-3: UNUSED. Read = 0000b, Write = don't care. Bit2: TR3: Timer 3 Run Control. This bit enables/disables Timer 3. 0: Timer 3 disabled. 1: Timer 3 enabled. T3M: Timer 3 Clock Select. This bit controls the division of the system clock supplied to Counter/Timer 3. 0: Counter/Timer 3 uses the system clock divided by 12. 1: Counter/Timer 3 uses the system clock. UNUSED. Read = 0, Write = don't care.
Bit1:
Bit0:
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Figure 17.21. TMR3RLL: Timer 3 Reload Register Low Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0x92
Bits 7-0: TMR3RLL: Timer 3 Reload Register Low Byte. Timer 3 is configured as an auto-reload timer. This register holds the low byte of the reload value.
Figure 17.22. TMR3RLH: Timer 3 Reload Register High Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value 00000000
SFR Address:
0x93
Bits 7-0: TMR3RLH: Timer 3 Reload Register High Byte. Timer 3 is configured as an auto-reload timer. This register holds the high byte of the reload value.
Figure 17.23. TMR3L: Timer 3 Low Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0x94
Bits 7-0: TMR3L: Timer 3 Low Byte. The TMR3L register is the low byte of Timer 3.
Figure 17.24. TMR3H: Timer 3 High Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0x95
Bits 7-0: TMR3H: Timer 3 High Byte. The TMR3H register is the high byte of Timer 3.
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PRELIMINARY
18. PROGRAMMABLE COUNTER ARRAY
The Programmable Counter Array (PCA) provides enhanced timer functionality while requiring less CPU intervention than the standard 8051 counter/timers. The PCA consists of a dedicated 16-bit counter/timer and five 16-bit capture/compare modules. Each capture/compare module has its own associated I/O line (CEXn) which is routed through the Crossbar to Port I/O when enabled (see Section 13.1 for details on configuring the Crossbar). The counter/timer is driven by a configurable timebase that can select between four inputs as its source: system clock divided by twelve, system clock divided by four, Timer 0 overflow, or an external clock signal on the ECI line. The PCA is configured and controlled through the system controller's Special Function Registers. The basic PCA block diagram is shown in Figure 18.1.
Figure 18.1. PCA Block Diagram
00 01 10 CPS=11 16-Bit Counter/Timer
System Clock
/12 /4
T0 Overflow
Capture/Compare Module 0
Capture/Compare Module 1
Capture/Compare Module 2
Capture/Compare Module 3
Capture/Compare Module 4
CEX0
CEX1
CEX2
CEX3
CEX4
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PRELIMINARY
18.1. Capture/Compare Modules
C8051F018 C8051F019
Each module can be configured to operate independently in one of four operation modes: Edge-triggered Capture, Software Timer, High Speed Output, or Pulse Width Modulator. Each module has Special Function Registers (SFRs) associated with it in the CIP-51 system controller. These registers are used to exchange data with a module and configure the module's mode of operation. Table 18.1 summarizes the bit settings in the PCA0CPMn registers used to place the PCA capture/compare modules into different operating modes. Setting the ECCFn bit in a PCA0CPMn register enables the module's CCFn interrupt. Note: PCA0 interrupts must be globally enabled before individual CCFn interrupts are recognized. PCA0 interrupts are globally enabled by setting the EA bit (IE.7) and the EPCA0 bit (EIE1.3) to logic 1. See Figure 18.2 for details on the PCA interrupt configuration.
Table 18.1. PCA0CPM Register Settings for PCA Capture/Compare Modules
ECOM CAPP CAPN MAT TOG PWM ECCF Operation Mode
X X
1 0
0 1 1 0 0 0
0 0 0 1 1 X
0 0 0 0 1 0
0 0 0 0 0 1
X X X X X X
X 1 1 0 1 0 1 0 X = Don't Care
Capture triggered by positive edge on CEXn Capture triggered by negative edge on CEXn Capture triggered by transition on CEXn Software Timer High Speed Output Pulse Width Modulator
Figure 18.2. PCA Interrupt Block Diagram
(for n = 0 to 4)
PCA0CPMn
ECCMT P E CA A AOWC OPP TGMC MP N n n n F nnn n PCA Counter/ Timer Overflow
PCA0CN
CC FR CCCCC CCCCC FFFFF 43210 C I D L
PCA0MD
CCE PPC SSF 10
0 1
ECCF0
PCA Module 0
ECCF1
0 1
EPCA0 (EIE1.3)
0 1
EA (IE.7)
0 1
Interrupt Priority Decoder
PCA Module 1
ECCF2
0 1
PCA Module 2
ECCF3
0 1
PCA Module 3
ECCF4
0 1
PCA Module 4
0 1
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18.1.1. Edge-triggered Capture Mode
PRELIMINARY
In this mode, a valid transition on the CEXn pin causes the PCA to capture the value of the PCA counter/timer and load it into the corresponding module's 16-bit capture/compare register (PCA0CPLn and PCA0CPHn). The CAPPn and CAPNn bits in the PCA0CPMn register are used to select the type of transition that triggers the capture: low-tohigh transition (positive edge), high-to-low transition (negative edge), or either transition (positive or negative edge). When a capture occurs, the Capture/Compare Flag (CCFn) in PCA0CN is set to logic 1 and an interrupt request is generated if CCF interrupts are enabled. The CCFn bit is not automatically cleared by hardware when the CPU vectors to the interrupt service routine, and must be cleared by software.
Figure 18.3. PCA Capture Mode Diagram
PCA Interrupt
PCA0CPMn
ECCMT P E C A A A OWC OPP TGMC MP N n n n F nnn n
0 000
PCA0CN
CC FR CCCCC CCCCC FFFFF 43210
0
Port I/O
Crossbar
CEXn
1 0 1
(to CCFn)
PCA0CPLn
PCA0CPHn
Capture
PCA Timebase
PCA0L
PCA0H
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PRELIMINARY
18.1.2. Software Timer (Compare) Mode
C8051F018 C8051F019
In Software Timer mode, the PCA counter/timer is compared to the module's 16-bit capture/compare register (PCA0CPHn and PCA0CPLn). When a match occurs, the Capture/Compare Flag (CCFn) in PCA0CN is set to logic 1 and an interrupt request is generated if CCF interrupts are enabled. The CCFn bit is not automatically cleared by hardware when the CPU vectors to the interrupt service routine, and must be cleared by software. Setting the ECOMn and MATn bits in the PCA0CPMn register enables Software Timer mode.
Figure 18.4. PCA Software Timer Mode Diagram
Write to PCA0CPLn Reset Write to PCA0CPHn 0
ENB
PCA Interrupt
ENB
1
PCA0CPMn
ECCMT P E C A A A OWC OPP TGMC MP N n n n F nnn n
00 00x Enable Match
PCA0CN PCA0CPLn PCA0CPHn
CC FR CCCCC CCCCC FFFFF 43210
16-bit Comparator
0 1
PCA Timebase
PCA0L
PCA0H
18.1.3. High Speed Output Mode
In this mode, each time a match occurs between the PCA Timer Counter and a module's 16-bit capture/compare register (PCA0CPHn and PCA0CPLn) the logic level on the module's associated CEXn pin will toggle. Setting the TOGn, MATn, and ECOMn bits in the PCA0CPMn register enables the High-Speed Output mode.
Figure 18.5. PCA High Speed Output Mode Diagram
Write to PCA0CPLn Reset Write to PCA0CPHn 0
ENB
ENB
PCA0CPMn
ECCMT P E C A A A OWC OPP TGMC MP N n n n F nnn n
00 0x PCA Interrupt
1
PCA0CN PCA0CPLn PCA0CPHn
CC FR CCCCC CCCCC FFFFF 43210
Enable
16-bit Comparator
Match
0 1
Toggle
PCA Timebase
TOGn
0 1
CEXn
Crossbar
Port I/O
PCA0L
PCA0H
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18.1.4. Pulse Width Modulator Mode
PRELIMINARY
All of the modules can be used independently to generate pulse width modulated (PWM) outputs on their respective CEXn pin. The frequency of the output is dependent on the timebase for the PCA counter/timer. The duty cycle of the PWM output signal is varied using the module's PCA0CPLn capture/compare register. When the value in the low byte of the PCA counter/timer (PCA0L) is equal to the value in PCA0CPLn, the output on the CEXn pin will be set. When the count value in PCA0L overflows, the CEXn output will be reset (see Figure 18.6). Also, when the counter/timer low byte (PCA0L) overflows from 0xFF to 0x00, PCA0CPLn is reloaded automatically with the value stored in the PCA0CPHn without software intervention. It is good practice to write to PCA0CPHn instead of PCA0CPLn to avoid glitches in the digital comparator. Setting the ECOMn and PWMn bits in the PCA0CPMn register enables Pulse Width Modulator mode.
Figure 18.6. PCA PWM Mode Diagram
PCA0CPHn
Write to PCA0CPLn Reset Write to PCA0CPHn 0
ENB
PCA0CPMn
ENB
1
E CCMT P E C A A AOWC OP P TGMC MP N n n n F nnn n
00x0 x Enable
PCA0CPLn
8-bit Comparator
match
S R
SET
Q Q
CEXn
Crossbar
Port I/O
CLR
PCA Timebase
PCA0L
Overflow
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PRELIMINARY
18.2. PCA Counter/Timer
C8051F018 C8051F019
The 16-bit PCA counter/timer consists of two 8-bit SFRs: PCA0L and PCA0H. PCA0H is the high byte (MSB) of the 16-bit counter/timer and PCA0L is the low byte (LSB). Reading PCA0L automatically latches the value of PCA0H at the same time. By reading the PCA0L Register first, this allows the PCA0H value to be held (at the time PCA0L was read) until the user reads the PCA0H Register. Reading PCA0H or PCA0L does not disturb the counter operation. The CPS1 and CPS0 bits in the PCA0MD register select the timebase for the counter/timer as shown in Table 18.2. When the counter/timer overflows from 0xFFFF to 0x0000, the Counter Overflow Flag (CF) in PCA0MD is set to logic 1 and an interrupt request is generated if CF interrupts are enabled. Setting the ECF bit in PCA0MD to logic 1 enables the CF flag to generate an interrupt request. The CF bit is not automatically cleared by hardware when the CPU vectors to the interrupt service routine, and must be cleared by software. (Note: PCA0 interrupts must be globally enabled before CF interrupts are recognized. PCA0 interrupts are globally enabled by setting the EA bit (IE.7) and the EPCA0 bit in EIE1 to logic 1.) Clearing the CIDL bit in the PCA0MD register allows the PCA to continue normal operation while the microcontroller core is in Idle mode.
Table 18.2. PCA Timebase Input Options
CPS1 0 0 1 1 CPS0 0 1 0 1 Timebase System clock divided by 12 System clock divided by 4 Timer 0 overflow High-to-low transitions on ECI (max rate = system clock divided by 4)
Figure 18.7. PCA Counter/Timer Block Diagram
IDLE
PCA0MD
C I D L CCE PPC SSF 10
PCA0CN
CC FR CCCCC CCCCC FFFFF 43210
PCA0L read or write To SFR Bus
Snapshot Register
SYSCLK/12 SYSCLK/4 Timer 0 Overflow ECI
00 01 10 11 0 1
PCA0H
PCA0L
Overflow CF To PCA Modules
To PCA Interrupt System
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18.3.
PRELIMINARY
Register Descriptions for PCA
The system device may implement one or more Programmable Counter Arrays. Following are detailed descriptions of the special function registers related to the operation of the PCA. The CIP-51 System Controller section of the datasheet provides additional information on the SFRs and their use.
Figure 18.8. PCA0CN: PCA Control Register
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
CF
Bit7
CR
Bit6
Bit5
CCF4
Bit4
CCF3
Bit3
CCF2
Bit2
CCF1
Bit1
CCF0
Bit0
(bit addressable)
00000000
SFR Address:
0xD8
Bit7:
CF: PCA Counter/Timer Overflow Flag. Set by hardware when the PCA Counter/Timer overflows from 0xFFFF to 0x0000. When the Counter/Timer Overflow (CF) interrupt is enabled, setting this bit causes the CPU to vector to the CF interrupt service routine. This bit is not automatically cleared by hardware and must be cleared by software. CR: PCA Counter/Timer Run Control. This bit enables/disables the PCA Counter/Timer. 0: PCA Counter/Timer disabled. 1: PCA Counter/Timer enabled. UNUSED. Read = 0, Write = don't care. CCF4: PCA Module 4 Capture/Compare Flag. This bit is set by hardware when a match or capture occurs. When the CCF interrupt is enabled, setting this bit causes the CPU to vector to the CCF interrupt service routine. This bit is not automatically cleared by hardware and must be cleared by software. CCF3: PCA Module 3 Capture/Compare Flag. This bit is set by hardware when a match or capture occurs. When the CCF interrupt is enabled, setting this bit causes the CPU to vector to the CCF interrupt service routine. This bit is not automatically cleared by hardware and must be cleared by software. CCF2: PCA Module 2 Capture/Compare Flag. This bit is set by hardware when a match or capture occurs. When the CCF interrupt is enabled, setting this bit causes the CPU to vector to the CCF interrupt service routine. This bit is not automatically cleared by hardware and must be cleared by software. CCF1: PCA Module 1 Capture/Compare Flag. This bit is set by hardware when a match or capture occurs. When the CCF interrupt is enabled, setting this bit causes the CPU to vector to the CCF interrupt service routine. This bit is not automatically cleared by hardware and must be cleared by software. CCF0: PCA Module 0 Capture/Compare Flag. This bit is set by hardware when a match or capture occurs. When the CCF interrupt is enabled, setting this bit causes the CPU to vector to the CCF interrupt service routine. This bit is not automatically cleared by hardware and must be cleared by software.
Bit6:
Bit5: Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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PRELIMINARY
Figure 18.9. PCA0MD: PCA Mode Register
R/W R/W R/W R/W R/W R/W R/W
C8051F018 C8051F019
R/W
Reset Value
CIDL
Bit7
Bit6
Bit5
Bit4
Bit3
CPS1
Bit2
CPS0
Bit1
ECF
Bit0
00000000
SFR Address:
0xD9
Bit7:
CIDL: PCA Counter/Timer Idle Control. Specifies PCA behavior when CPU is in Idle Mode. 0: PCA continues to function normally while the system controller is in Idle Mode. 1: PCA operation is suspended while the system controller is in Idle Mode.
Bits6-3: UNUSED. Read = 0000b, Write = don't care. Bits2-1: CPS1-CPS0: PCA Counter/Timer Pulse Select. These bits select the timebase source for the PCA counter. CPS1 0 0 1 1 Bit0: CPS0 0 1 0 1 Timebase System clock divided by 12 System clock divided by 4 Timer 0 overflow High-to-low transitions on ECI (max rate = system clock divided by 4)
ECF: PCA Counter/Timer Overflow Interrupt Enable. This bit sets the masking of the PCA Counter/Timer Overflow (CF) interrupt. 0: Disable the CF interrupt. 1: Enable a PCA Counter/Timer Overflow interrupt request when CF (PCA0CN.7) is set.
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PRELIMINARY
Figure 18.10. PCA0CPMn: PCA Capture/Compare Registers
R/W R/W R/W R/W R/W R/W R/W R/W Reset Value
Bit7
ECOMn
Bit6
CAPPn
Bit5
CAPNn
Bit4
MATn
Bit3
TOGn
Bit2
PWMn
Bit1
ECCFn
Bit0
00000000
SFR Address: 0xDA-0xDE
PCA0CPMn Address:
PCA0CPM0 = 0xDA (n = 0) PCA0CPM1 = 0xDB (n = 1) PCA0CPM2 = 0xDC (n = 2) PCA0CPM3 = 0xDD (n = 3) PCA0CPM4 = 0xDE (n = 4)
Bit7: Bit6:
UNUSED. Read = 0, Write = don't care. ECOMn: Comparator Function Enable. This bit enables/disables the comparator function for PCA module n. 0: Disabled. 1: Enabled. CAPPn: Capture Positive Function Enable. This bit enables/disables the positive edge capture for PCA module n. 0: Disabled. 1: Enabled. CAPNn: Capture Negative Function Enable. This bit enables/disables the negative edge capture for PCA module n. 0: Disabled. 1: Enabled. MATn: Match Function Enable. This bit enables/disables the match function for PCA module n. When enabled, matches of the PCA counter with a module's capture/compare register cause the CCFn bit in PCA0MD register to be set. 0: Disabled. 1: Enabled. TOGn: Toggle Function Enable. This bit enables/disables the toggle function for PCA module n. When enabled, matches of the PCA counter with a module's capture/compare register cause the logic level on the CEXn pin to toggle. 0: Disabled. 1: Enabled. PWMn: Pulse Width Modulation Mode Enable. This bit enables/disables the comparator function for PCA module n. When enabled, a pulse width modulated signal is output on the CEXn pin. 0: Disabled. 1: Enabled. ECCFn: Capture/Compare Flag Interrupt Enable. This bit sets the masking of the Capture/Compare Flag (CCFn) interrupt. 0: Disable CCFn interrupts. 1: Enable a Capture/Compare Flag interrupt request when CCFn is set.
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
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PRELIMINARY
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Figure 18.11. PCA0L: PCA Counter/Timer Low Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xE9
Bits 7-0: PCA0L: PCA Counter/Timer Low Byte. The PCA0L register holds the low byte (LSB) of the 16-bit PCA Counter/Timer.
Figure 18.12. PCA0H: PCA Counter/Timer High Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address:
0xF9
Bits 7-0: PCA0H: PCA Counter/Timer High Byte. The PCA0H register holds the high byte (MSB) of the 16-bit PCA Counter/Timer. Note the value read is actually from the snapshot register in order to synchronize it with PCA0L.
Figure 18.13. PCA0CPLn: PCA Capture Module Low Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address: 0xEA-0xEE
PCA0CPLn Address:
PCA0CPL0 = 0xEA (n = 0) PCA0CPL1 = 0xEB (n = 1) PCA0CPL2 = 0xEC (n = 2) PCA0CPL3 = 0xED (n = 3) PCA0CPL4 = 0xEE (n = 4)
Bits7-6: PCA0CPLn: PCA Capture Module Low Byte. The PCA0CPLn register holds the low byte (LSB) of the 16-bit capture module n.
Figure 18.14. PCA0CPHn: PCA Capture Module High Byte
R/W Bit7 R/W Bit6 R/W Bit5 R/W Bit4 R/W Bit3 R/W Bit2 R/W Bit1 R/W Bit0 Reset Value
00000000
SFR Address: 0xFA-0xFE
PCA0CPHn Address:
PCA0CPH0 = 0xFA (n = 0) PCA0CPH1 = 0xFB (n = 1) PCA0CPH2 = 0xFC (n = 2) PCA0CPH3 = 0xFD (n = 3) PCA0CPH4 = 0xFE (n = 4)
Bits7-0: PCA0CPHn: PCA Capture Module High Byte. The PCA0CPHn register holds the high byte (MSB) of the 16-bit capture module n.
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19. JTAG (IEEE 1149.1)
PRELIMINARY
Each MCU has an on-chip JTAG interface and logic to support boundary scan for production and in-system testing, Flash read and write operations, and non-intrusive in-circuit debug. The JTAG interface is fully compliant with the IEEE 1149.1 specification. Refer to this specification for detailed descriptions of the Test Interface and BoundaryScan Architecture. Access of the JTAG Instruction Register (IR) and Data Registers (DR) are as described in the Test Access Port and Operation of the IEEE 1149.1 specification. The JTAG interface is via four dedicated pins on the MCU, which are TCK, TMS, TDI, and TDO. These pins are all 5V tolerant. Through the 16-bit JTAG Instruction Register (IR), any of the eight instructions shown in Figure 19.1 can be commanded. There are three Data Registers (DR's) associated with JTAG Boundary-Scan, and four associated with Flash read/write operations on the MCU.
Figure 19.1. IR: JTAG Instruction Register
Reset Value
0x0004
Bit15 Bit0
IR value 0x0000 0x0002 0x0004 0xFFFF 0x0082 0x0083 0x0084 0x0085
Instruction EXTEST SAMPLE/ PRELOAD IDCODE BYPASS Flash Control Flash Data Flash Address Flash Scale
Description Selects the Boundary Data Register for control and observability of all device pins Selects the Boundary Data Register for observability and presetting the scanpath latches Selects device ID Register Selects Bypass Data Register Selects FLASHCON Register to control how the interface logic responds to reads and writes to the FLASHDAT Register Selects FLASHDAT Register for reads and writes to the Flash memory Selects FLASHADR Register which holds the address of all Flash read, write, and erase operations Selects FLASHSCL Register which controls the prescaler used to generate timing signals for Flash operations
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PRELIMINARY
19.1. Boundary Scan
C8051F018 C8051F019
The Data Register in the Boundary Scan path is an 87-bit shift register. The Boundary DR provides control and observability of all the device pins as well as the SFR bus and Weak Pullup feature via the EXTEST and SAMPLE commands.
Table 19.1. Boundary Data Register Bit Definitions
EXTEST provides access to both capture and update actions, while Sample only performs a capture. Bit
0
Action Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update Capture Update
Target Reset Enable from MCU Reset Enable to /RST pin Reset input from /RST pin Reset output to /RST pin External Clock from XTAL1 pin Not used Weak pullup enable from MCU Weak pullup enable to Port Pins SFR Address Bus bit from CIP-51 (e.g. Bit4=SFRA0, Bit5=SFRA1...) SFR Address Bus bit to SFR Address Bus (e.g. Bit4=XSFRA0, Bit5=XSFRA1) SFR Data Bus bit read from SFR (e.g. Bit12=SFRD0, Bit13=SFRD1...) SFR Data Bus bit written to SFR (e.g. Bit12=SFRD0, Bit13=SFRD1...) SFR Write Strobe from CIP-51 SFR Write Strobe to SFR Bus SFR Read Strobe from CIP-51 SFR Read Strobe to SFR Bus SFR Read/Modify/Write Strobe from CIP-51 SFR Read/Modify/Write Strobe to SFR Bus P0.n output enable from MCU (e.g. Bit23=P0.0, Bit25=P0.1, etc.) P0.n output enable to pin (e.g. Bit23=P0.0oe, Bit25=P0.1oe, etc.) P0.n input from pin (e.g. Bit24=P0.0, Bit26=P0.1, etc.) P0.n output to pin (e.g. Bit24=P0.0, Bit26=P0.1, etc.) P1.n output enable from MCU (e.g. Bit39=P1.0, Bit41=P1.1, etc.) P1.n output enable to pin (e.g. Bit39=P1.0oe, Bit41=P1.1oe, etc.) P1.n input from pin (e.g. Bit40=P1.0, Bit42=P1.1, etc.) P1.n output to pin (e.g. Bit40=P1.0, Bit42=P1.1, etc.) P2.n output enable from MCU (e.g. Bit55=P2.0, Bit57=P2.1, etc.) P2.n output enable to pin (e.g. Bit55=P2.0oe, Bit57=P2.1oe, etc.) P2.n input from pin (e.g. Bit56=P2.0, Bit58=P2.1, etc.) P2.n output to pin (e.g. Bit56=P2.0, Bit58=P2.1, etc.) P3.n output enable from MCU (e.g. Bit71=P3.0, Bit73=P3.1, etc.) P3.n output enable to pin (e.g. Bit71=P3.0oe, Bit73=P3.1oe, etc.) P3.n input from pin (e.g. Bit72=P3.0, Bit74=P3.1, etc.) P3.n output to pin (e.g. Bit72=P3.0, Bit74=P3.1, etc.)
1
2
3
4-11
12-19
20
21
22 23,25,27,29, 31,33,35,37 24,26,28,30, 32,34,36,38 39,41,43,45, 47,49,51,53 40,42,44,46, 48,50,52,54 55,57,59,61, 63,65,67,69 56,58,60,62, 64,66,68,70 71,73,75,77, 79,81,83,85 72,74,76,78, 80,82,84,86
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19.1.1. EXTEST Instruction
PRELIMINARY
The EXTEST instruction is accessed via the IR. The Boundary DR provides control and observability of all the device pins as well as the SFR bus and Weak Pullup feature. All inputs to on-chip logic are set to one.
19.1.2. SAMPLE Instruction
The SAMPLE instruction is accessed via the IR. The Boundary DR provides observability and presetting of the scan-path latches.
19.1.3. BYPASS Instruction
The BYPASS instruction is accessed via the IR. It provides access to the standard 1-bit JTAG Bypass data register.
19.1.4. IDCODE Instruction
The IDCODE instruction is accessed via the IR. It provides access to the 32-bit Device ID register.
Figure 19.2. DEVICEID: JTAG Device ID Register
Version
Bit31 Bit28 Bit27
Part Number
Bit12 Bit11
Manufacturer ID
Bit1
1
Bit0
Reset Value (part dpdnt)
Version = 0000b (Revision A) = 0001b (Revision B) Part Number = 0000 0000 0000 0010b (C8051F018/9) Manufacturer ID = 0010 0100 001b (Cygnal Integrated Products)
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19.2. Flash Programming Commands
C8051F018 C8051F019
The Flash memory can be programmed directly over the JTAG interface using the Flash Control, Flash Data, Flash Address, and Flash Scale registers. These Indirect Data Registers are accessed via the JTAG Instruction Register. Read and write operations on indirect data registers are performed by first setting the appropriate DR address in the IR register. Each read or write is then initiated by writing the appropriate Indirect Operation Code (IndOpCode) to the selected data register. Incoming commands to this register have the following format: 19:18 IndOpCode 17:0 WriteData
IndOpCode: These bit set the operation to perform according to the following table: IndOpCode 0x 10 11 Operation Poll Read Write
The Poll operation is used to check the Busy bit as described below. Although a Capture-DR is performed, no Update-DR is allowed for the Poll operation. Since updates are disabled, polling can be accomplished by shifting in/out a single bit. The Read operation initiates a read from the register addressed by the IR. Reads can be initiated by shifting only 2 bits into the indirect register. After the read operation is initiated, polling of the Busy bit must be performed to determine when the operation is complete. The write operation initiates a write of WriteData to the register addressed by the IR. Registers of any width up to 18 bits can be written. If the register to be written contains fewer than 18 bits, the data in WriteData should be leftjustified, i.e. its MSB should occupy bit 17 above. This allows shorter registers to be written in fewer JTAG clock cycles. For example, an 8-bit register could be written by shifting only 10 bits. After a Write is initiated, the Busy bit should be polled to determine when the next operation can be initiated. The contents of the Instruction Register should not be altered while either a read or write operation is in progress. Outgoing data from the indirect Data Register has the following format: 19 0 18:1 ReadData 0
Busy
The Busy bit indicates that the current operation is not complete. It goes high when an operation is initiated and returns low when complete. Read and Write commands are ignored while Busy is high. In fact, if polling for Busy to be low will be followed by another read or write operation, JTAG writes of the next operation can be made while checking for Busy to be low. They will be ignored until Busy is read low, at which time the new operation will initiate. This bit is placed at bit 0 to allow polling by single-bit shifts. When waiting for a Read to complete and Busy is 0, the following 18 bits can be shifted out to obtain the resulting data. ReadData is always right-justified. This allows registers shorter than 18 bits to be read using a reduced number of shifts. For example, the result from a byte-read requires 9 bit shifts (Busy + 8 bits).
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C8051F018 C8051F019
PRELIMINARY
Figure 19.3. FLASHCON: JTAG Flash Control Register
Reset Value
WRMD3
Bit7
WRMD2
Bit6
WRMD1
Bit5
WRMD0
Bit4
RDMD3
Bit3
RDMD2
Bit2
RDMD1
Bit1
RDMD0
Bit0
00000000
This register determines how the Flash interface logic will respond to reads and writes to the FLASHDAT Register. Bits7-4: WRMD3-0: Write Mode Select Bits. The Write Mode Select Bits control how the interface logic responds to writes to the FLASHDAT Register per the following values: 0000: A FLASHDAT write replaces the data in the FLASHDAT register, but is otherwise ignored. 0001: A FLASHDAT write initiates a write of FLASHDAT into the memory location addressed by the FLASHADR register. FLASHADR is incremented by one when complete. 0010: A FLASHDAT write initiates an erasure (sets all bytes to 0xFF) of the Flash page containing the address in FLASHADR. FLASHDAT must be 0xA5 for the erase to occur. FLASHADR is not affected. If FLASHADR = 0x7DFE - 0x7DFF, the entire user space will be erased (i.e. entire Flash memory except for Reserved area 0x7E00 - 0x7FFF). (All other values for WRMD3-0 are reserved.) Bits3-0: RDMD3-0: Read Mode Select Bits. The Read Mode Select Bits control how the interface logic responds to reads to the FLASHDAT Register per the following values: 0000: A FLASHDAT read provides the data in the FASHDAT register, but is otherwise ignored. 0001: A FLASHDAT read initiates a read of the byte addressed by the FLASHADR register if no operation is currently active. This mode is used for block reads. 0010: A FLASHDAT read initiates a read of the byte addressed by FLASHADR only if no operation is active and any data from a previous read has already been read from FLASHDAT. This mode allows single bytes to be read (or the last byte of a block) without initiating an extra read. (All other values for RDMD3-0 are reserved.)
Figure 19.4. FLASHADR: JTAG Flash Address Register
Reset Value
0x0000
Bit15
Bit0
This register holds the address for all JTAG Flash read, write, and erase operations. This register autoincrements after each read or write, regardless of whether the operation succeeded or failed. Bits15-0: Flash Operation 16-bit Address.
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PRELIMINARY
C8051F018 C8051F019
Figure 19.5. FLASHDAT: JTAG Flash Data Register
Reset Value
DATA7
Bit9
DATA6
Bit8
DATA5
Bit7
DATA4
Bit6
DATA3
Bit5
DATA2
Bit4
DATA1
Bit3
DATA0
Bit2
FAIL
Bit1
FBUSY
Bit0
0000000000
This register is used to read or write data to the Flash memory across the JTAG interface. Bits9-2: DATA7-0: Flash Data Byte. Bit1: FAIL: Flash Fail Bit. 0: Previous Flash memory operation was successful. 1: Previous Flash memory operation failed. Usually indicates the associated memory location was locked. FBUSY: Flash Busy Bit. 0: Flash interface logic is not busy. 1: Flash interface logic is processing a request. Reads or writes while FBUSY = 1 will not initiate another operation
Bit0:
Figure 19.6. FLASHSCL: JTAG Flash Scale Register
Reset Value
FOSE
Bit7
FRAE
Bit6
Bit5
Bit4
FLSCL3
Bit3
FLSCL2
Bit2
FLSCL1
Bit1
FLSCL0
Bit0
00000000
This register controls the Flash read timing circuit and the prescaler required to generate the correct timing for Flash operations. Bit7: FOSE: Flash One-Shot Enable Bit. 0: Flash read strobe is a full clock-cycle wide. 1: Flash read strobe is 50nsec. FRAE: Flash Read Always Bit. 0: The Flash output enable and sense amplifier enable are on only when needed to read the Flash memory. 1: The Flash output enable and sense amplifier enable are always on. This can be used to limit the variations in digital supply current due to switching the sense amplifiers, thereby reducing digitally induced noise.
Bit6:
Bits5-4: UNUSED. Read = 00b, Write = don't care. Bits3-0: FLSCL3-0: Flash Prescaler Control Bits. The FLSCL3-0 bits control the prescaler used to generate timing signals for Flash operations. Its value should be written before any Flash operations are initiated. The value written should be the smallest integer for which: FLSCL[3:0] > log2(fSYSCLK / 50kHz) Where fSYSCLK is the system clock frequency. All Flash read/write/erase operations are disallowed when FLSCL[3:0] = 1111b.
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C8051F018 C8051F019
19.3. Debug Support
PRELIMINARY
Each MCU has on-chip JTAG and debug circuitry that provide non-intrusive, full speed, in-circuit debug using the production part installed in the end application using the four pin JTAG I/F. Cygnal's debug system supports inspection and modification of memory and registers, setting breakpoints, watchpoints, single stepping, and run and halt commands. No additional target RAM, program memory, or communications channels are required. All the digital and analog peripherals are functional and work correctly (remain in sync) while debugging. The WDT is disabled when the MCU is halted during single stepping or at a breakpoint. The C8051F015DK is a development kit with all the hardware and software necessary to develop application code and perform in-circuit debugging with the C8051F018/9. Each kit includes an Integrated Development Environment (IDE) which has a debugger and integrated 8051 assembler. It has an RS-232 to JTAG protocol translator module referred to as the EC. There is also a target application board with a C8051F015 installed and with a large prototyping area. The kit also includes RS-232 and JTAG cables, and wall-mount power supply.
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PRELIMINARY
Disclaimers
C8051F018 C8051F019
Life support: These products are not designed for use in life support appliances or systems where malfunction of these products can reasonably be expected to result in personal injury. Cygnal Integrated Products customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Cygnal Integrated Products for any damages resulting from such applications. Right to make changes: Cygnal Integrated Products reserves the right to make changes, without notice, in the products, including circuits and/or software, described or contained herein in order to improve design and/or performance. Cygnal Integrated Products assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask work infringement, unless otherwise specified.
Trademarks
The Cygnal's logo, CIP-51, and Cygnal are trademarks of Cygnal Integrated Products, Inc. I2C is a trademark of Philips Semiconductors SMBus and MCS-51 are trademarks of Intel Corporation SPI is a trademark of Motorola, Inc.
CYGNAL Integrated Products, Inc. www.cygnal.com
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