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CDB5471
CDB5471 Evaluation Board and Software
Features
l Direct
General Description
The CDB5471 is an inexpensive tool designed to evaluate the functionality/performance of the CS5471 2channel A/D Converter. In addition to this data sheet, the CS5471 Data Sheet is required in conjunction with the CDB5471 Evaluation Board. Two terminal-block connectors serve as inputs to the CS5471's two analog input pairs. The CDB5471 includes an optional voltage reference source for CS5471. A 4.096MHz crystal is provided as a source for CS5471's XIN pin, or an external clock source can be supplied by the user. Digital output data from the CS5471 is transferred to the user's IBM-compatible PC via the included 25-pin parallel port cable. The CDB5471 includes PC software, allowing the user to perform data capture (includes option for time domain analysis, histogram analysis, and frequency domain analysis). The software also allows real-time RMS calculation/analysis to be performed simultaneously on the instantaneous data from both channels. ORDERING INFORMATION CDB5471
VAVA+ +5 VIN GND VD+
Shunt Sensor and Current Transformer Interface for 3-Phase Power Voltage Reference crystal for XIN
l On-Board l On-board l Digital l Lab
Interface to PC
Windows/CVITM Evaluation Software
"Real-Time" RMS calculation FFT Analysis Time Domain Analysis Noise Histogram Analysis
Evaluation Board
Charge Pump Circuitry
3V Regulator
(Not Populated)
Control Switches
VIN1+ VIN1IIN1+ IIN1VIN2+ VIN2IIN2+ IIN2VIN3+ VIN3IIN3+ IIN3-
CPD
VAVA+ GAIN OWRS
RESET FSO SDO CLK SE
Reset Circuit Serial-toParallel Interface Crystal 4.096 MHz
DB25
To PC
CS5451
XIN VREF IN OUT Header
VREF Voltage Reference
Preliminary Product Information
P.O. Box 17847, Austin, Texas 78760 (512) 445 7222 FAX: (512) 445 7581 http://www.cirrus.com
This document contains information for a new product. Cirrus Logic reserves the right to modify this product without notice.
Copyright (c) Cirrus Logic, Inc. 2001 (All Rights Reserved)
FEB `01 DS480DB1 1
CDB5471
TABLE OF CONTENTS
1. INTRODUCTION ....................................................................................................................... 4 1.1 CS5471 .............................................................................................................................. 4 1.2 Data Flow on Evaluation Board ......................................................................................... 4 2. HARDWARE ............................................................................................................................. 5 2.1 Evaluation Board Description ............................................................................................. 5 2.2 Power Supply Connections ................................................................................................ 5 2.2.1 Analog Power Supply ............................................................................................ 5 2.2.2 Digital Power Supply ............................................................................................. 5 2.2.3 Charge Pump Options ........................................................................................... 6 2.3 Eval Board Control - Headers/Switches ............................................................................. 6 2.3.1 Analog Inputs ........................................................................................................ 8 2.3.2 Voltage Reference Input ....................................................................................... 9 2.3.3 Clock Source for XIN ............................................................................................. 9 2.3.4 S1 DIP Switch ....................................................................................................... 9 2.3.5 Reset Circuit .......................................................................................................... 9 2.3.6 External Signal In/Out Header .............................................................................. 9 2.3.7 Serial-to-Parallel Interface ..................................................................................... 9 2.3.8 Connecting the Eval Board to PC ....................................................................... 10 3. SOFTWARE ............................................................................................................................ 14 3.1 Installing the Software ...................................................................................................... 14 3.2 Running the Software ...................................................................................................... 14 3.2.1 Getting Started .................................................................................................... 14 3.2.2 The Start-Up Window .......................................................................................... 15 3.2.3 The Conversion Window ..................................................................................... 15 3.2.4 Data Collection Window ...................................................................................... 17 3.2.5 Config Window .................................................................................................... 18 3.2.6 Analyzing Data .................................................................................................... 19 3.2.7 Time Domain Information .................................................................................... 19 3.2.8 Frequency Domain Information ........................................................................... 20 3.2.9 Histogram Information ......................................................................................... 21
Contacting Cirrus Logic Support
For a complete listing of Direct Sales, Distributor, and Sales Representative contacts, visit the Cirrus Logic web site at: http://www.cirrus.com/corporate/contacts/sales.cfm
IBM, AT and PS/2 are trademarks of International Business Machines Corporation. Windows is a trademark of Microsoft Corporation. Lab Windows and CVI are trademarks of National Instruments. SPITM is a trademark of Motorola. MicrowireTM is a trademark of National Semiconductor.
Preliminary product information describes products which are in production, but for which full characterization data is not yet available. Advance product information describes products which are in development and subject to development changes. Cirrus Logic, Inc. has made best efforts to ensure that the information contained in this document is accurate and reliable. However, the information is subject to change without notice and is provided "AS IS" without warranty of any kind (express or implied). No responsibility is assumed by Cirrus Logic, Inc. for the use of this information, nor for infringements of patents or other rights of third parties. This document is the property of Cirrus Logic, Inc. and implies no license under patents, copyrights, trademarks, or trade secrets. No part of this publication may be copied, reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photographic, or otherwise) without the prior written consent of Cirrus Logic, Inc. Items from any Cirrus Logic website or disk may be printed for use by the user. However, no part of the printout or electronic files may be copied, reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photographic, or otherwise) without the prior written consent of Cirrus Logic, Inc.Furthermore, no part of this publication may be used as a basis for manufacture or sale of any items without the prior written consent of Cirrus Logic, Inc. The names of products of Cirrus Logic, Inc. or other vendors and suppliers appearing in this document may be trademarks or service marks of their respective owners which may be registered in some jurisdictions. A list of Cirrus Logic, Inc. trademarks and service marks can be found at http://www.cirrus.com.
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LIST OF FIGURES
Figure 1. Power Supply, CS5471, and Oscillator .............................................. 11 Figure 2. Analog Inputs ..................................................................................... 12 Figure 3. Digital Circuitry ................................................................................... 13 Figure 4. Start-Up Window ................................................................................ 15 Figure 5. Conversion Window ........................................................................... 16 Figure 6. Data Collection Window (Time Domain) ............................................ 17 Figure 7. Configuration Window ........................................................................ 19 Figure 8. Data Collection Window (FFT) ........................................................... 20 Figure 9. Data Collection Window (Histogram) ................................................. 21 Figure 10.Silkscreen ........................................................................................... 22 Figure 11.Circuit Side ......................................................................................... 23 Figure 12.Solder Side......................................................................................... 24
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1. INTRODUCTION
The CDB5471 Evaluation Board demonstrates the performance of the CS5471 6-channel A/D converter. The CDB5471 evaluation board provides a quick means of evaluating the CS5471. Analysis software supplied with the CDB5471 allows the user to observe the CS5471's digital output data on the user's PC monitor. The PC software allows the user to quantify the device's performance in the timedomain and frequency domain. The user can save raw data from the CS5471 to a data file, which allows to user to analyze performance with other tools that may be preferable to the user. Additional features of CS5471 include a charge pump driver, on-chip 1.2 V reference, and a digital input that can select between two different output word rates. (The two output word rates are equal to XIN/2048 and XIN/1024.) The CS5471 requires a 1.2 V reference input on VREFIN. The modulators and high rate digital filters allow the user to measure instantaneous voltage and current at an output word rate of 4 kHz (or 2000 kHz, depending on the state of the OWRS pin) when a 4.096 MHz clock source is used.
1.2 Data Flow on Evaluation Board
The output serial bit-stream from the CS5471 is shifted into an 8-bit latch circuit so that it can be quickly ported to the DB25 connector. From this connector, the data can be sent through the provided 25-pin printer cable to the parallel port of the user's IBM-compatible PC (the PC must run under Windows `95/'98/2000 operating system). Once the 8-bit segments of data are ported to the user's PC, the LabWindows software (included with this kit) will re-segment the data into the appropriate 16-bit word format for both of the CS5471's two data channels. The data is sent quickly to the user's PC, which allows the software to perform various data processing and graphical illustrations on the digital output data. This includes real-time RMS, variance, and standard deviation calculations for both channels. The output data from each channel can be plotted on-screen in the time domain or in the frequency domain. A histogram function is also included to help the user to evaluate the noise characteristics of each channel. The software can also calculate the mean and standard deviation of the output codes both channels. This feature allows the user to scrutinize the variation of the A/D converters if the user applies constant DC voltage levels to the inputs. RMS calculation is also provided to assist in the quick analysis AC input signals.
1.1 CS5471
The CS5471 is a highly integrated Two-Channel Delta-Sigma Analog-to-Digital Converter (ADC) developed for power measurement/metering applications. However the CS5471 has other potential uses in various data acquisition applications, particularly in motor/servo control applications which require very high precision. The CS5471 combines two delta-sigma modulators with decimation filters, along with a master-mode serial interface on a single chip device. The CS5471 was designed for the purpose of performing the A/D conversion operations required at the front-end of a digital singlephase metering system. The six ADC channels can be thought of as a pair of voltage/current-channel ADC's in a digital single-phase power metering application. The CS5471 contains one programmable gain amplifier (PGA) for the current input. The PGA sets the maximum input level of the current channel at 800 mV DC (for gain = 1x) or 40 mV DC (for gain = 20x). The voltage channel has only the 1x gain setting, and so the range of input levels on the voltage channel is 800 mV DC.
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2. HARDWARE 2.1 Evaluation Board Description
The CDB5471 board contains circuitry that will: * Accept appropriate DC voltage levels from the user's +3V and/or +5V power supplies, and direct this power to the VA+, VD+, VA- and DGND pins of the CS5471. * Direct the six analog input signals to the six input pairs of the CS5471. * Supply necessary voltage reference input for the CS5471's VREFIN pin. * Supply appropriate crystal/oscillator stimulus to the CS5471's XIN pin. * Direct the output driver signal from the CS5471's charge-pump driver pin (CPD) which is used produce the negative power supply source for the CS5471's VA- pin. * Provide a reset switch that allows the user to set the CS5471's RESET pin from logic "1" to logic "0". * Provide two DIP switches which allow the user to set the logic levels on the CS5471's GAIN and OWRS input pins. * Detect and receive the data frame signal and digital serial output data signals from the CS5471's FSO and SDO pins, and send this output data through the included parallel cable, and up to user's PC. Several areas of blank proto-board space are provided so that, if desired, the user can interface their own electronic sensor equipment onto the board. The output from these sensors can be wired to the two nearby analog input terminal block connectors, which is then fed to the two analog input channels of the CS5471. Examples of such sensors would include voltage and current transformers, shunt resistors, and resistor divider networks. The next section of this document describes the various sections of the board. After this, operation of the PC software is described in detail.
2.2 Power Supply Connections
The CDB5471 can be used in several different power supply configurations. Table 1 shows the various possible power connections with the required jumper settings. There are various +3 V and +5 V options. The user must supply the +3V, +5V, GND, and sometimes -2V voltage levels needed to power the evaluation board.
2.2.1 Analog Power Supply
Referring to Figure 1, the A+ post supplies power to the positive analog power input pin (VA+) of the CS5471. This post also supplies power to the LT1004 voltage reference (D3) and the optional +3V regulator (U5). If HDR9 is set to the "A-" setting, the A- post can supply the required negative voltage to the VA- pin of the CS5471. Note that the evaluation board contains the footprints and connectivity which allows the user to install a LM317 voltage regulator (U5), which can be used to create +3 V from a +5 V supply. This option is useful if the user wants to interface the evaluation board to another board that can only operate from a +5V supply. With HDR17 set to "+5V_IN", one single +5 V supply can be used to provide both a +5V to various microcontrollers and/or other peripheral devices, as well as +3 V for the CS5471. The included schematic diagram shows the circuitry for the +5V regulator circuitry inside a box with dashed lines. These components are not populated when the board is shipped from the factory, but the user can install these components if desired.
2.2.2 Digital Power Supply
The A+ post can be used to supply both the analog power (to CS5471 VA+ pin) as well as the digital power (to CS5471 VD+ pin). However if a separate supply voltage is desired for the digital power
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CDB5471
supply, the "VD+" banana connector post can be used to independently supply a separate digital power supply to the input of the CS5471 (VD+ pin), the 4.096 MHz oscillator (U1), and circuitry for the parallel port interface. This is controlled by the setting on HDR18. The user should note that the CS5471 can operate with a digital supply voltage of either +3V or +5V. This voltage is defined as the voltage presented across VD+ and DGND. ferring to Figure 1, circuitry for a charge-pump circuit is included on-board. The charge pump circuit consists of capacitors C11, C12, and C36, and diodes D1 and D2. As an alternative to using the charge pump circuit, the user can supply an off-board -2V DC power source to the "A-" banana connector. This option is controlled by the setting on HDR9.
2.3 Eval Board Control - Headers/Switches
Table 2 lists the various adjustable headers and switches on the CDB5471 Evaluation Board, as well as their default settings (as shipped from the factory). The header settings can be adjusted by the user to select various options on the evaluation board. These options are described further in the following paragraphs.
2.2.3 Charge Pump Options
The output from CS5471's charge-pump driver pin (CPD) can be used to generate a -2V supply when the proper jumper settings are selected on HDR9. This -2V supply can be used as the negative power supply connection for the CS5471's VA- pin. RePower Supplies Analog +3 +3 +3 +3 +3 +3 +3 +3 +3 +3 +5 Digital +3 +3 +3 +3 +3 +3 +5 +5 +5 +5 +3 A+ +3 +3 +3 +3 NC NC +3 +3 NC NC +5
Power Post Connections A-2 -2 NC NC -2 NC -2 NC -2 NC 0 GND 0 0 0 0 0 0 0 0 0 0 +2 D+ +3 NC +3 NC NC NC +5 +5 +5 +5 +5 +5 V_IN NC NC NC NC +5 +5 NC NC +5 +5 NC HDR9
A- O O CPD O O A- O O CPD O O AO CPD O AO CPD O O O O O
HDR17
+5V_IN O A+ O +5V_IN O A+ O +5V_IN O A+ O +5V_IN O A+ O +5V_IN O O A+ +5V_IN O A+ O +5V_IN O A+ O +5V_IN O A+ O +5V_IN O A+ O +5V_IN O A+ O +5V_IN O A+ O O O O O O O O O O O O O O O O O O O O O O O
HDR18
VD+ O V+ O VD+ O V+ O VD+ O V+ O VD+ O V+ O VD+ O V+ O VD+ O V+ O VD+ O V+ O VD+ O V+ O VD+ O V+ O VD+ O V+ O VD+ O V+ O O O O O O O O O O O O O O O O O O O O O O O
A- O O CPD O O AO CPD O O O
A- O O CPD O O AO CPD O O O
A- O O CPD O O AO CPD O O O
A- O O CPD O O
Table 1. Power Supply Connections
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Name HDR1
Function Description Used to switch IIN3+ on the CS5471 between J2 and AGND. Used to switch VIN3- on the CS5471 between J3 and AGND. Used to switch VIN3+ on the CS5471 between J1 and AGND. Used to switch IIN3- on the CS5471 between J4 and AGND. Used to switch VIN2- on the CS5471 between J6 and AGND. Used to switch IIN2+ on the CS5471 between J7 and AGND. Used to switch IIN2- on the CS5471 between J5 and AGND. Used to switch VIN2+ on the CS5471 between J8 and AGND. Used to switch between external VA- and on-board CS5471 charge-pump circuit, CPD Used to switch VIN1+ on the CS5471 between J9 and AGND. Used to switch IIN1- on the CS5471 between J12 and AGND. Used to switch IIN1+ on the CS5471 between J10 and AGND. S1-1 sets logic level on CS5471 GAIN input pin S1-2 sets logic level on CS5471 OWRS input pin Used to switch VIN1- on the CS5471 between J11 and AGND. Used to switch the VREFIN from external VREF post connector, to the on board LT1004 reference, or to the on-chip reference VREFOUT. Refer to Table 3.
Default Setting IIN3+ Set to BNC J2
Default Jumpers
O O O IIN3+ O AGND
HDR2
VIN3- Set to BNC J3
O O O O
O VIN3O AGND O VIN3+ O AGND
HDR3
VIN3- Set to BNC J1
HDR4
IIN3- Set to BNC J4
O O O O O O
O IIN3O AGND O VIN2O AGND O IIN2+ O AGND
HDR5
VIN2- Set to BNC J6
HDR6
IIN2+ Set to BNC J7
HDR7
IIN2+ Set to BNC J5
O O O O A- O CPD O O O O O O O
2
O IIN2O AGND O VIN2+ O AGND O O O VIN1+ O AGND O IIN1O AGND O IIN1+ O AGND
3
HDR8
VIN2+ Set to BNC J8
HDR9
CPD active
HDR10
VIN1+ Set to BNC J9
HDR11
IIN1- Set to BNC J12
HDR12
IIN1- Set to BNC J10
SW1
SW1-2 Open (GAIN=x1) SW1-1 Open (XIN/1024)
OPEN
HDR13
VIN1- Set to BNC J11 VREFIN Set to onchip reference VREFOUT
O O
O VIN1O AGND
HDR14
O O O
O LT1004 O VREFOUT O EXT VREF
Table 2. Default Header Settings
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CDB5471
Name HDR15 HDR16 HDR17 Function Description Controls the source for the CS5471 XIN clock input. This header should always be shorted. Determines whether the main analog supply will be powered from the A- post, or from the regulated 3V voltage (generated from the +5V_IN) post input. Choose whether the digital circuitry will be powered by main analog supply, or powered by separate digital supply (through VD+ post). Default Setting Set to on-board 4.000 MHz crystal (U1). Short this header Set to ASet to main analog supply Default Jumpers
O O O O EXT XIN O DGND O 4.0096 MHz OSC O O O O O +5V_IN O A+
HDR18
VD+ O V+ O
O O
Table 2. Default Header Settings (Continued)
2.3.1 Analog Inputs
Refer to Figure 2. The settings on the 14 analog input headers (2 headers per channel) which are designated as HDR10 through HDR13, determine which of the input lines will carry a signal, and which input lines may be grounded. They can be configured to accept either a single-ended or differential signal. Using the voltage channel as an example (see Figure 2), note that HDR10 sets the input to the positive side of the first voltage channel input (VIN1+ pin). HDR13 sets the input to the negative side of the first voltage channel input (VIN1- pin). In a single-ended input configuration, HDR13 would be set to the "AGND" setting, and HDR10 would be set to "VIN1+" and would conduct the single-ended signal. In a differential input configuration, HDR13 would be set to "VIN1-" and HDR10 would be set to "VIN1+" and this pair of inputs would form the differential input pair into the VIN1+ and VIN1- pins of the CS5471. WARNING: DANGER! One of the possible applications for the CS5471 includes data acquisition for a power metering system. However, the user should not attempt to directly connect any leads from a high-voltage power line to the evaluation board inputs, even if the current/voltage levels are gain reduced by resistive dividers and/or shunts. Because the ground terminal of the parallel cable (from the PC) is near or at earth ground potential,
8
the ground node on the evaluation board will also be forced to earth ground potential. Serious damage and even personal injury can occur if a "hot" voltage main is connected to any point on the evaluation board, including the analog input connectors. Such power line signals must be isolated by current/voltage transformers and reduced in magnitude before they can be safely applied to the evaluation board. Several patch-circuit areas are provided near the voltage/current input headers, in case the user wants to connect special sensor circuitry to the analog inputs (such as transformers, shunt resistors, etc., for sensory the voltage/current on a singlephase power line). For the input channel, a Shunt Resistor or Current Transformer can be mounted in these areas and connections can be made to currentchannel input pair. Likewise, the three channels, a Voltage Divider or Voltage Transformer can be connected to the CS5471's voltage input pair. Note from Figure 2 that a simple R-C network filters each sensor's output to reduce any interference picked up by the input leads. The 3 dB corner of the filter is approximately 50 kHz differential and common mode. Note that the CDB5471 Evaluation Board is also used as the evaluation board for the CS5451 A/D converter, which is a 6-channel version of the CS5471. The user can use this board to the evaluDS480DB1
CDB5471
ate CS5451 by obtaining a CS5451 sample and connect it in place of the CS5471 device. Then the remaining four input channels serve as the inputs to the CS5451's four additional input pairs. Other header options listed in Table 2 allow the user to set the source of the input clock signal and the source of the voltage reference (VREFIN) input, etc. The voltage reference options and clock input options are discussed next.
2.3.4 S1 DIP Switch
Referring to Figure 3, the two single-pole singlethrow switches on SW1 DIP switch should be used to control the logic settings on the CS5471's OWRS pin and GAIN pin. When these SW1 switches are set to "OPEN" the corresponding pin on CS5471 is set to D+ potential, which creates a logic-high state. When the user closes either of these SW1 switches, the corresponding pin on CS5471 is grounded, which creates a logic-low state on the pin.
2.3.2 Voltage Reference Input
To supply the CS5471 with a suitable 1.2 V voltage reference input at the VREFIN pin, the evaluation board provides three voltage reference options: onchip, on-board, and external. See HDR14 as shown in Figure 1. Table 3 illustrates the available voltage reference settings for HDR14. With HDR14's
Reference Description Select on board LT1004 Reference LT1004 (5 ppm/C) Select reference supVREFOUT plied from CS5471 VREFOUT pin EXTVREF Select external reference HDR14
O O O O O O O O O O O O O O O O O O
LT1004 VREFOUT EXT VREF LT1004 VREFOUT EXT VREF LT1004 VREFOUT EXT VREF
2.3.5 Reset Circuit
Circuitry has been provided which allows the user to execute a hardware reset on the CS5471. (See Figure 3). By pressing on the S1 switch, the RESET pin on the CS5471 will be held low until the switch is released.
2.3.6 External Signal In/Out Header
Note that HDR16 is included on the CDB5471 Evaluation Board as a header that is normally left unconnected. This header provides a way for the user to interface the CDB5471 Evaluation Board to other prototype boards, calibrators, logic analyzers, other peripherals, etc. in order to further evaluate the CS5471 device and/or to use the evaluation board as a platform for the prototype development of a digital power metering solution. However, note that the CDB5471 Evaluation Board is not intended to be integrated directly into a commercial digital power meter. The layout of the board is not optimized for practical power metering situations.
Table 3. Reference Selection
jumpers in position "VREFOUT," the CS5471's on-chip reference provides 1.2 volts. With HDR14 set to position "LT1004," the LT1004 provides 1.23 volts (the LT1004 temperature drift is typically 50 ppm/C). By setting HDR14's jumpers to position "EXT VREF," the user can supply an external voltage reference to J16 connector post (VREF) and AGND inputs.
2.3.7 Serial-to-Parallel Interface
Glue-logic on the evaluation board converts the CS5471 serial data into 8-bit segments (bytes). The bytes are sent to the DB25 connector (J17), and then through the standard printer cable to the user's PC. This section briefly describes the operation of the digital circuitry on the CDB5471 that provides the 8-bit parallel data to the PC. Refer to Figure 3.
2.3.3 Clock Source for XIN
A 4.000 MHz crystal is provided to drive the XIN input of the CS5471. (See Figure 1.) However, the user has the option to provide an external oscillator signal for XIN, by switching the setting of HDR15.
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The user should recall from CS5471 Data Sheet that the serial interface on the CS5471 device is a "master-mode" interface, which means that the device provides the clock. Once the CS5471 is powered on, the SCLK pin produces a clock signal, and data is sent out on the SDO pin of the device. When the evaluation software is instructed (by the user) to acquire data through the parallel interface, a twostep process is performed: First the software synchronizes itself to the frame rate of the CS5471, then the software acquires multiple frames of data from the CS5471. After sixteen SCLKs, the PC software has acquired two bytes (16 bits) which represents one data sample. The 4-bit up/down counter (U6) will roll over after every 16 SCLKs. (Note that U6 is cleared by the CS5471's FSO signal at the beginning of each frame, which insures that the counter begins the frame in the correct state--cleared). This sequence, which lasts for 16 SCLKs, is performed a total of six times, although only the first two repetitions of this sequence are relevant. In the first two sequences, the two 16-bit words from the CS5471 are acquired by the PC. The data contained in the remaining four sequence executions will be meaningless, as the state of the CS5471's SDO pin is be undefined during the last 64 clocks of each data frame. After the sixth 16-bit word is acquired, the software recognizes that the end of a data frame has been reached, and it will continue to wait for the next transition on the "BUSY" line. This will not occur until the first 8 SCLKs of the next frame are sent from the CS5471. Various other signals in Figure 3 (STRB, FEED, ACK, etc.) are not used during data capture and are only used for testing (internal use only).
2.3.7.1. Synchronization
When the software is commanded to acquire data, the software will first synchronize itself to the frame rate of the CS5471 (see CS5471 Data Sheet). This is done by measuring the amount of time between rising and falling edges of the "BUSY" signal. (BUSY will change state every time the CS5471 issues eight SCLKs--See next section for a more detailed description.) By measuring this time period, the software can determine the idle period of the frame, which allows it to be prepared to collect a complete frame's worth of data when the next CS5471 frame is received. This acquisition sequence is described next.
2.3.8 Connecting the Eval Board to PC
The CDB5471 connects to the user's IBM-compatible PC with the included 25-pin parallel port cable. The user should not connect this cable between the CDB5471 and the parallel port on the PC until all of the header options in Table 2 have been set to appropriate settings and the user has applied power to the CDB5471. The parallel cable attached to the CDB5471 Evaluation Board at J17. After connecting the parallel port cable between the PC and CDB5471, the user should always actuate (press down on) the "RESET" switch (S1) at least one time before performing any other evaluation activities.
2.3.7.2. Acquisition
Referring to Figure 3, the CS5471's SCLK line is used to clock the 8-bit serial-in/parallel-out shiftregister (U7) which accepts the serial data on SDO and shifts it into the 8 output bits QA-QG. The SCLK signal is also fed into the up/down counter U6 and after every 8 SCLKs, the "QC" pin of U6 will latch the QA-QG output bits of U6 into the 8bit D-Flip-Flop (U3). While this is happening, the software monitors the "BUSY" signal (from the "QD" pin of U6). BUSY is the critical handshake signal. A rising or falling transition on BUSY indicates to the software that it is now time to collect another byte of data from the latched output on U3.
10
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100
J21
Z4 P6KE6V8P
C42 10UF
C39 .1UF
C40 .1UF
C41 22UF
1
140
R31
R29
1K
R30
CON_BANANA
HDR17 HDR2X2
3 1 4 2
V+
A+
J14
R2 R3 4.99K TP40 TP1
2
L1 10 FERRITE_BEAD TP40 TP76
GND
VA+ VAVIN3+ VIN3IN3+ IN3-
IIN1+ IIN1VIN2+ VIN2IIN2+
GND
C19
3
C16 .1UF
.1UF
VIN3+ VIN3IN3+ IN3-
BNC_RA
D3 LT1004
J13
GND
2
HDR2X2 HDR9
4
1
Z1 P6KE6V8P
C15 47UF C1 .1UF
TANT 2.2UF C12
3
DS480DB1 11
+5V
CON_BANANA
U5 LM317LZ
3
TP40 TP77
2
+5V_IN
IN
OUT ADJ
3.0V
D+ GND
V+
HDR18 HDR2X2
1 3 2 4
GND
C38 .33UF TANT
U4
Do Not Populate
CON_BANANA
SCLK SDO FSO SE /GAIN
GND
J18
GND
C20 .1UF
VIN3+ VIN3IN3+ IN3-
TP36 TP38 TP40 TP42 TP44 TP46 TP48 TP50 TP52 TP54 TP56 TP58 TP60 TP62 4.7UF TANT
TP37 TP39 TP41 TP43 TP45 TP47 TP49 TP51 TP53 TP55 TP57 TP59 TP61 TP63
1 2 3 4 5 6 7 8 9 10 11 12 13
SCLK SDO FSO SE /GAIN AGND VREFIN VREFOUT VA+ VAVIN3+ VIN3IN3+ IN3-
VD+ DGND CPD XIN /RESET OWRS VIN1+ VIN1IIN1+ IIN1VIN2+ VIN2IIN2+
14
IIN2-
28 27 26 25 24 23 22 21 20 19 18 17 16 15
TP79 TP73 TP74 TP14 TP17 TP19 TP21 TP23 TP25 TP27 TP29 TP31 TP33 TP35
TP78 TP72 TP75 TP15 TP16 TP18 TP20 TP22 TP24 TP26 TP28 TP30 TP32 TP34
HDR1X2 HDR16 12
CON_BANANA
VD+
C21
XIN /RESET OWRS VIN1+ VIN1IIN1+ IIN1VIN2+ VIN2IIN2+ IIN2-
C14 C22 .1UF .1UF C23 47UF Z3 J20 P6KE6V8P
10UF
GND
GND GND
+3V
GND
C37
SSOP28_200_P65MM
U2
SCLK SDO FSO SE /GAIN
1 2 3 4 5 6 7 8 9 10 11 12 13
SCLK SDO FSO SE /GAIN AGND VREFIN VREFOUT VD+ DGND CPD XIN /RESET OWRS VIN1+ VIN1-
Z2
P6KE6V8P
C13 47UF
C17 .1UF
HDR3X2 HDR14
2 1 3 5 4 6
1.2V
+3V
14
IIN2-
28 27 26 25 24 23 22 21 20 19 18 17 16 15
XIN /RESET OWRS VIN1+ VIN1IIN1+ IIN1VIN2+ VIN2IIN2+ IIN2-
GND
EXT_IN
GND
CON_BANANA
GND
GND
SKT_SSOP28_ENP
GND
4.0960MHZ C18 .1UF
14 7
HDR3X2 HDR15
2 4 6 1 3 5
EXT VREF
J16
GND
8
TP2 TP40 TANT 4.7UF
D+
XIN
R32
10
VCC U1
GND
C36
CON_BANANA
C2.1UF
AJ15
GND
D2 BAT85
C11 .039UF D1 BAT85
CDB5471
GND GND
Figure 1. Power Supply, CS5471, and Oscillator
1 2 3 4
GND
J25
J23
1 2 3 4
GND
GND
1 2 3 4
12
J22
1 2 3 4
TP67
J5 BNC_RA
R23
301 0.1% C8 4700PF TP66
GND
HDR2X2 HDR7
1 3 2 4
IIN2-
C24 .01UF
J7 BNC_RA
R22
301 0.1%
GND
HDR2X2 HDR6
1 3 2 4
GND IIN2+
C25 .01UF
TP65
J6 BNC_RA
R21
301 0.1% C7 4700PF TP64
GND
HDR2X2 HDR5
1 3 2 4
GND VIN2-
C26 .01UF
J8 BNC_RA
R24
301 0.1%
GND
HDR2X2 HDR8
1 3 2 4
GND VIN2+
C27 .01UF
GND
J24
1 2 3 4
1 2 3 4
TP4
J12 BNC_RA
TP71
HDR2X2 HDR11
1 3 2 4
J1
R26
301 0.1% C9 4700PF TP5
GND
R19
IIN1-
BNC_RA
301 0.1% C6
GND
HDR2X2 HDR3
1 3 2 4
VIN3+
C28 .01UF 4700PF TP70
C32 .01UF
J10 BNC_RA
R27
301 0.1%
GND
HDR2X2 HDR12
1 3 2 4
GND IIN1+
J3 BNC_RA
R18
301 0.1%
GND
HDR2X2 HDR2
1 3 2 4
GND VIN3-
C29 .01UF TP69
C33 .01UF
TP6
J11 BNC_RA
R28
301 0.1% C10 4700PF TP3
GND
HDR2X2 HDR13
1 3 2 4
GND VIN1-
J2 BNC_RA
R17
301 0.1% C5
GND
HDR2X2 HDR1
1 3 2 4
GND IN3+
C30 .01UF 4700PF TP68
C34 .01UF
J9 BNC_RA
R25
301 0.1%
GND
HDR2X2 HDR10
1 3 2 4
GND VIN1+
J4 BNC_RA
R20
301 0.1%
GND
HDR2X2 HDR4
1 3 2 4
GND IN3-
C31 .01UF
C35 .01UF
CDB5471
J26
GND
J27
GND
DS480DB1
Figure 2. Analog Inputs
MM74HC193N
GND
GND
BUSY INIT
U8
GND
19 11 13 15 17
2/G 2A1 2A2 2A3 2A4 2Y1 2Y2 2Y3 2Y4
9 7 5 3
R15 R7
D+
4.7K 470 C45
R9
470
SE ACK
SN74HC240N
10K 10K
220PF COG
GND
SW1
R6
10K
OPEN
/GAIN OWRS
R35 R34
10K 10K
R33
R16
GND
GND
GND
10K
10K
U8
D+
R4
VCC 1Y1 1Y2 1Y3 1Y4 GND
1/G 1A1 1A2 1A3 1A4
SCLK
R11
470
18 16 14 12 10
2 4 6 8
R12 R14
4.7K 4.7K
STRB FEED
R5
20
1
R1
D+
GND
.1UF
C44
10K
DS480DB1
OWRS /RESET /GAIN SE FSO SCLK SDO
HDR7X2 HDR19 1 2 3 4 5 6 7 8 9 10 11 12 13 14
C43 .1UF
GND
D+
D+
U6
1 2 3 4 5 6 7 QD 8 GND DATA C DATA D 16 15 14 13 12 11 10 9
DATA B QB QA CD CU QC
VCC DATA A CLR BORROW CARRY LOAD
R8
470
FSO
D+
DB25M_RA J17 1 14 2 15 3 16 4 17 5 18 6 19 7 20 8 21 9 22 10 23 11 24 12 25 13
GND
2 1
SW_DIP_2
SN74HC374N SN74HC164N
7 13 12 11 10 6 5 4 3 14
.1UF C4
10 20 19 16 15 12 9 6 5 2
GND VCC
18 17 14 13 8 7 4 3 11 1
D+
/RESET
R10 R36
D+
GND
SDO
470
20K R37 49.9 S1 SW_B3W_1100
2 1 8 9
B A CLK /CLR U7
GND
QG QF QE QD QC QB QA VCC
8D 7D 6D 5D 4D 3D 2D 1D CLK /OC U3 R13
8Q 7Q 6Q 5Q 4Q 3Q 2Q 1Q
C46 .1UF
GND
C3 .1UF
D+
4.7K
SEL D+ GND
CDB5471
SN74HC240N
GND
Figure 3. Digital Circuitry 13
CDB5471
3. SOFTWARE
The evaluation software was developed with Lab Windows/CVITM, a software development package from National Instruments. The software is designed to run under Windows 95TM or later, and requires about 3 MB of hard drive space (2 MB for the CVI Run-Time EngineTM, and 1 MB for the evaluation software). After installing the software, read the readme.txt file for any last minute updates or changes. More sophisticated analysis software can be developed by purchasing the development package from National Instruments (512-794-0100).
Note: The software is written to run with 640 x 480 resolution; however, it will work with 1024 x 768 resolution. If the user interface seems to be a little small, the user might consider setting the display settings to 640 x 480. (640x480 was chosen to accommodate a variety of computers).
3.2 Running the Software 3.2.1 Getting Started
The CDB5471 Evaluation software allows the user to obtain, display, and save data that is acquired by the CS5471 chip. Before running the software, the first step is to make sure that all of the headers that are listed in Table 2 are set to an appropriate setting, the exact setting should be determined by the user. Next, with the user's DC power supplies still turned off, the user should connect the necessary power leads to the banana jack power connectors on the evaluation board. Refer to Table 1 for various acceptable power supply connection configurations. Then at this time the user should turn on their DC power supplies, which should apply power to the CDB5471. Several test point locations are available on the evaluation board. The user can check these test points with a voltmeter, to make sure that the voltages at these test points are at the expected levels. When the user has verified that the power supply levels are constant, the user should connect the included 25-pin cable between J17 of the evaluation board and the parallel port on the user's PC. The user should then press down on the S1 "RESET" switch, and make sure to hold it down for at least ~0.5 seconds before releasing. Finally, the user can start the PC software. To start the software, double click on the EVAL5451 icon, or initiate through the Start menu.
3.1 Installing the Software
Installation Procedure: 1) Turn on the PC, running Windows 95TM or later. 2) Insert the Installation Diskette #1 into the PC. 3) Select the Run option from the Start menu. 4) At the prompt, type: A:\SETUP.EXE . 5) The program will begin installation. 6) If it has not already been installed on the PC, the user will be prompted to enter the directory in which to install the LabWindows CVI RunTime EngineTM. The Run-Time EngineTM manages executables created with Lab Windows/CVITM. If the default directory is acceptable, select OK and the Run-Time EngineTM will be installed there. 7) After the Run-Time EngineTM is installed, the user is prompted to enter the directory in which to install the CDB5471 software. Select OK to accept the default directory. 8) Once the program is installed, it can be run by double clicking on the EVAL5451 icon, or through the Start menu.
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CDB5471
Figure 4. Start-Up Window
3.2.2 The Start-Up Window
When the software first executes, the user should see the Start-Up Window appear on the user's PC monitor. This window is shown in Figure 4. From this window, the user can navigate to three other main windows: the Conversion Window, the Data Collection Window, and CS5471 Pinout Diagram. (The CS5451 Pinout Diagram is also included in a fourth window.) To navigate to these windows, use the mouse to click on the "Menu" item, which is located towards the upper left corner of the Start-Up Window. "Menu" is a pull-down menu which contains four options. From this pull-down menu, the user can select any of the three windows mentioned above, and once this is done, the new window should appear. A fourth option called "Exit" should be selected when the user wants to terminate execution of the evaluation board software program. If the user selects the "CS5471 Pinout Diagram" option in the "Menu" pull-down, the software will
DS480DB1
display a window which contains the pin diagram of the CS5471. This pin diagram is included for the user's reference. Note that this window has no actual functionality. The functionality of the Conversion Window and the Data Collection Window is described next.
3.2.3 The Conversion Window
Refer to Figure 5. After the user presses on the green-colored "START" button in this window, the software will begin to collect data for both channels of the CS5471. For each channel, a certain number of instantaneous data samples from the CS5471 are bundled together. The period over which each bundle of samples is taken is called a "computation cycle." The user controls the number of instantaneous data samples that will be taken (per channel) during one computation cycle by adjusting the number in the box labeled "Evaluation Software Cycle Count:." Note that the default value for this is set to 4000. Thus during every computation cycle, the PC software will acquire 4000 samples
15
CDB5471
(from both channels) and it will update the onscreen results of both channels after calculating the results on each successive set of 4000 samples. The results that are displayed on this screen are therefore updated after each computation cycle. Note that the results in the very first computation cycle (after the "START" button has been activated) will not be valid. Accuracy of the Mean, Std. Dev. and RMS results will increase as the "Samples to Average" value is increased. The user should understand how to interpret the values that are displayed in the array of number boxes in the Conversion Window. For CDB5471, only the results displayed in the "Voltage 1" and "Current 1" rows are valid. The result values that are displayed in these numeric output boxes are all expressed on a normalized scale. The highest value (0.999...) represents the highest digital output code that can be issued from the CS5471 (which is +32767), while the lowest value -0.999... represents the most negative output code that can be issued from the CS5471 (which is -32768). This is because the CS5471 issues instantaneous output codes as two's complement 16-bit words. Therefore, the range of values that can be returned from the CS5471 are between -32768 and +32767. The CS5471 issues instantaneous data, and every computation cycle, the software computes/displays the quantities which are described below:
Figure 5. Conversion Window
16
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CDB5471
Figure 6. Data Collection Window (Time Domain)
3.2.3.1. Last Value
The first column is labelled as "Last Value." The value in this box represents the value of the very last instantaneous sample that was taken (for both channels) in the most recently-completed computation cycle. If the user's analog input waveforms are AC in nature, then this column of results will rarely have any meaning. But if the user applies a constant DC input signal to any of the analog input channels, then the Last Value column for that channel should display an output code that is relatively constant from one conversion cycle to the next.
3.2.3.4. RMS
The values in this column represent the computed RMS value over the most recently-completed computation cycle.
3.2.4 Data Collection Window
The Data Collection Window (Figs 6, 8, and 9) allows the user to collect samples sets of data from CS5471 and analyze them using time domain, FFT, and histogram plots. The Data Collection Window is accessible through the Menu option, or by pressing F4.
3.2.3.2. Mean
The values in this column represent the simple average of the sample values in the latest computation cycle.
3.2.4.1. Collect Button
This button will collect data from the CS5471, to be analyzed in the plot area. See the section on Collecting Data Sets for more information.
3.2.3.3. Std Dev.
The values in this column represent the computed standard deviation over the set of values in the most recent computation cycle.
DS480DB1
17
CDB5471
3.2.4.2. Time Domain / FFT / Histogram Selector
This selector button is located just to the right of the Collect Button. The label on this button will change as the user selects which analysis is to be performed ("Time Domain" or "FFT" or "Histogram"). When the software is first started, the default mode on this selector button is Time Domain. This user should click on this button to select which type of data processing to perform on the collected data and display in the plot area. Refer to the section on Analyzing Data for more information.
3.2.4.6. Save Button
The red-colored SAVE button will save the data in the current plot to a file. The exact path and filename can be specified by the user in the text window located just to the left of the SAVE button. The data collected for both channels will be saved to a text file.
3.2.4.7. Load Button
The green colored LOAD button will load any data file that was previously generated by clicking on the red SAVE button. The exact path and filename must be specified by the user in the text window located just to the left of the LOAD button.
3.2.4.3. "Crystal" Value Indicator Box
The value in this box reflects the frequency of the CS5451's clock input (at the XIN pin). Since the XIN frequency affects the sampling rate (the output word rate) of the CS5451, this information must be specified to the software so that it can accurately depict the frequency-content of the sampled data (in Hz) when performing an FFT analysis. The user can enter the crystal frequency that is used on the CDB5451 board into this box. The default value of this box is set for the on-board 4.096MHz oscillator.
3.2.4.8. Channel Selector Buttons
Clicking on buttons labeled as "V1" and "I1" will display a certain channel of data. "V1" refers to the voltage data taken across the Vin1+/Vin1- pins of the CS5471. In a similar manner, clicking on the "I1" button will display the data representing the voltage level across the current channel input pins (Iin1+/Iin1-).
3.2.5 Config Window
See Figure 7. Clicking on the Config button will bring up a small pop-up window called the Config Window. The Config Window allows the user to set up the data collection and analysis parameters, which are described next.
3.2.4.4. OWRS Pin Setting:
This switch should be adjusted whenever the user toggles the S1-1 DIP switch (on the evaluation board). The default setting of this switch is HI, corresponding to the default setting on S1-1 (default setting is "OPEN"). S1-1 drives the CS5471's OWRS pin to logic "1". A logic "1" on OWRS sets the sampling frequency of both CS5471 input channels to XIN/1024. To toggle the state of the on-screen switch, simply click on the switch with the mouse.
3.2.5.1. Number of Samples
This box allows the user to select the number of samples to collect. The user can choose any wholenumber power of 2 between 16 and 32768.
3.2.5.2. Average
When performing FFT processing, this box will determine the number of FFTs to average. FFTs will then be collected and averaged when the user clicks on the Collect Button.
3.2.4.5. Config Button
This button will bring up the configuration window (shown in Fig 7) in which the user can modify the data collection specifications. See the discussion of the Config Window in this document.
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CDB5471
all six channels). The number of samples that are actually saved is equal to the number specified in the Number of Samples box.
3.2.5.6. Ready Button
After the user has adjusted the parameters in the Config Window to the desired settings, the user must click on the READY button to close the Config Window and return to the Data Collection Window.
3.2.6 Analyzing Data
The evaluation software provides three types of analysis tests - Time Domain, Frequency Domain, and Histogram. The Time Domain analysis processes acquired conversions to produce a plot of Output Code versus Conversion Sample Number. The Frequency Domain analysis processes acquired conversions to produce a magnitude versus frequency plot using the Fast-Fourier transform (results up to Fs/2 are calculated and displayed). The Histogram analysis test processes acquired conversions to produce a histogram plot. Statistical noise calculated are also calculated and displayed.
Figure 7. Configuration Window
3.2.5.3. FFT Window
This box allows the user to select the type of windowing algorithm for FFT processing. Windowing algorithms include the Blackman, Black-Harris, Hanning, 5-term Hodie, and 7-term Hodie. The 5term Hodie and 7-term Hodie are windowing algorithms developed at Cirrus Logic.
3.2.7 Time Domain Information
The following controls and indicators are associated with the Time Domain Analysis. Time domain data can be plotted in the Data Collection Window by setting the Time Domain / FFT / Histogram selector to "Time Domain."
3.2.5.4. Histogram Bin Width
This box allows for a variable "bin width" when plotting histograms of the collected data. Each vertical bar in the histogram plot will contain the number of output codes contained in this box. Increasing this number may allow the user to view histograms with larger input ranges.
3.2.7.1. Count
Displays current x-position of the cursor on the time domain display.
3.2.5.5. Samples to Discard
This number represents the number of CS5471 sample periods that will be ignored before the software starts to collect samples (when the user presses on the Collect Button). After the software has skipped over this many data samples, the software will then begin to save samples from the device (for
DS480DB1
3.2.7.2. Magnitude
Displays current y-value of the cursor on the time domain display.
3.2.7.3. Maximum
Indicator for the maximum value of the collected data set.
19
CDB5471
3.2.7.4. Minimum
Indicator for the minimum value of the collected data set.
3.2.8.3. S/D
Indicator for the Signal-to-Distortion Ratio, 4 harmonics are used in the calculations (decibels).
3.2.8 Frequency Domain Information
The following section describes the indicators associated with FFT (Fast-Fourier Transform) analysis. Refer to Figure 8. FFT data can be plotted in the Data Collection Window by setting the Time Domain / FFT / Histogram selector button to "FFT."
3.2.8.4. SINAD
Indicator for the Signal-to-Noise + Distortion Ratio (decibels).
3.2.8.5. SNR
Indicator for the Signal-to-Noise Ratio, first 4 harmonics are note included (decibels).
3.2.8.1. Frequency
Displays the x-axis value of the cursor on the FFT display.
3.2.8.6. S/PN
Indicator for the Signal-to-Peak Noise Ratio (decibels).
3.2.8.2. Magnitude
Displays the y-axis value of the cursor on the FFT display.
3.2.8.7. FS-PdB
Not using windowing, how far down from zero the peak voltage input value is (decibels).
Figure 8. Data Collection Window (FFT)
20
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CDB5471
3.2.9 Histogram Information
See figure 9. The following is a description of the indicators associated with Histogram Analysis. Histogram can plotted in the Data Collection Window by setting the Time Domain / FFT / Histogram selector to "Histogram."
3.2.9.4. Variance
Indicator for the calculated variance of the collected data set.
3.2.9.5. STD_DEV
Indicator for the calculated standard deviation of the collected data set.
3.2.9.1. Bin
Displays the x-axis value of the cursor on the Histogram.
3.2.9.6. Maximum
Indicator for the maximum value of the collected data set.
3.2.9.2. Magnitude
Indicator for the maximum value of the collected data set.
3.2.9.7. Minimum
Indicator for the minimum value collected in the data set.
3.2.9.3. Mean
Average value of the collected data set.
Figure 9. Data Collection Window (Histogram)
DS480DB1
21
CDB5471
Figure 10. Silkscreen
22
DS480DB1
CDB5471
Figure 11. Circuit Side
DS480DB1
23
CDB5471
Figure 12. Solder Side
24
DS480DB1
* Notes *

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