View CS8415A-IZ_2475288.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

preliminary product information this document contains information for a new product. cirrus logic reserves the right to modify this produ ct without notice. 1 copyright ? cirrus logic, inc. 2002 (all rights reserved) cirrus logic, inc. http://www.cirrus.com features ! complete eiaj cp120 1, iec-60958, aes3, s/pdif compatible receiver ! +5 v analog supply (va) ! +3 v to +5 v digital interface supply (vl) ! 7:1 s/pdif input mux ! flexible 3-wire serial digital output port ! 8 khz to 96 khz sample frequency range ! low jitter clock recovery ! pin and microcontroll er read access to channel status and user data ! microcontroller and standalone modes ! differential cable receiver ! on-chip channel status and user data buffer memories ! auto-detection of compressed audio input streams ! decodes cd q sub-code ! omck system clock mode general description the cs8415a is a monolithic cmos device which re- ceives and decodes one of 7 channels of audio data according to the iec60958, s/pdif, eiaj cp1201, or aes3. the cs8415a has a seri al digital audio output port and comprehensive cont rol ability through a 4-wire microcontroller port. channel status and user data are assembled in block sized buffers, making read access easy. a low jitter clock recovery mechanism yields a very clean recovered clock from the incoming aes3 stream. stand-alone operation allows systems with no micro- controller to operate the cs8415a with dedicated output pins for channel status data. target applications inclu de a/v receivers, cd-r, dvd receivers, multimedia speakers, digital mixing consoles, effects processors, set-top boxes, and computer and automotive audio systems. ordering infomation cs8415a-cs 28-pin soic -10 to +70c cs8415a-cz 28-pin tssop -10 to +70c cs8415a-is 28-pin soic -40 to +85c CS8415A-IZ 28-pin tssop -40 to +85c cdb8415a evaluation board i clock & data recovery misc. control serial audio output receiver aes3 s/pdif decoder c&ubit data buffer control port & registers rxn0 rxp6 olrck osclk sdout rst emph u sda/ cdout scl/ cclk ad1/ cdin ad0/ cs int va+ agnd filt rerr vl+ dgnd h/s rmck rxp5 rxp4 rxp3 rxp2 rxp1 rxp0 7:1 mux omck cs8415a 96 khz digital audio interface receiver jan ?03 ds470pp4
cs8415a 2 table of contents 1. characteristics and specifications ........................................................................ 5 specified operating conditions . .............. ................ ............. ............. ............. ........... 5 absolute maximum ratings ...... ................ ................ ................ ............. ............. ........... 5 dc electrical characteristics................................................................................... 6 digital input characteristics ..................................................................................... 6 digital interface specifications................................................................................ 6 switching characteristics .......................................................................................... 6 switching characteristics - serial audio ports................................................. 7 switching characteristics - control port - spi mode...................................... 8 switching characteristics - control port - i2c mode ...................................... 9 2. typical connection diagram ...................................................................................... 10 3. general description ..................................................................................................... 11 3.1 aes3 and s/pdif standards documents ........ ................ ............. ............. ............. ......... 11 4. serial audio output port ............................................................................................ 12 5. aes3 receiver ............................................................................................................. ....... 14 5.1 7:1 s/pdif input multiplexer ............................................................................................ 14 5.2 omck system clock mode ............................................................................................. 14 5.3 pll, jitter attenuation, and varispeed ............................................................................ 14 5.4 error reporting and hold function .................................................................................. 14 5.5 channel status data handlin g ......................................................................................... 15 5.6 user data handling ........................................................................................................ .. 15 5.7 non-audio auto-detection ............................ ................................................................... 15 5.8 mono mode operation ..................................................................................................... 15 6. control port description and timing .................................................................... 17 6.1 spi mode .................................................................................................................. ....... 17 6.2 i2c mode .................................................................................................................. ....... 17 6.3 interrupts ................................................................................................................ .......... 18 7. control port register summary ............................................................................. 19 7.1 memory address pointer (map) ....................................................................................... 19 8. control port register bit definitions .................................................................. 20 8.1 control 1(01h) ............................................................................................................. ...... 20 8.2 control 2 (02h) ............................................................................................................ ...... 20 8.3 clock source control (04h)............................................................................................... 21 contacting cirrus logic support for all product questions and inquiries cont act a cirrus logic sa les representative. to find one nearest you go to iimportant notice "preliminary" product information describes products that are in production, but for which full characterization data is not ye t available. "advance" product infor- mation describes products that are in development and subject to development changes. cirrus logic, inc. and its subsidiaries ( "cirrus") believe that the infor- mation contained in this document is accurate and reliable. however, the information is subject to change without notice and i s provided "as is" without warranty of any kind (express or implied). customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. all products are sold subject to the terms and conditions of sale supplied at the time of o rder acknowledgment, including those pertaining to warranty, patent infringement, and limitation of liability. no responsibility is assumed by cirrus for the use o f this information, including use of this information as the basis for manufacture or sale of any items, or for infringement of patents or other rights of third parties. this document is the property of cirrus and by furnishing this information, cirrus grants no license, express or implied under any patents, mask work rights, copyright s, trademarks, trade secrets or other intellectual property rights. cirrus owns the copyrights of the information contained herein and gives consent for copie s to be made of the information only for use within your organization with respect to cirrus integrated circuits or other parts of cirrus. this consent does not ex tend to other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale. an export permit needs to be obtained from the competent authorities of the japanese government if any of the products or techn ologies described in this ma- terial and controlled under the "foreign exchange and foreign trade law" is to be exported or taken out of japan. an export li cense and/or quota needs to be obtained from the competent authorities of the chinese government if any of the products or technologies described in this mate rial is subject to the prc foreign trade law and is to be exported or taken out of the prc. certain applications using semiconductor products may involve potential risks of death, personal injury, or severe property or environmental damage ("critical applications") . cirrus products are not desi gned, authorized , or warrant- ed to be suitable for use in li fe-support devices or systems or other critic al applications. incl usion of cirrus products in such applications is understood to be fully at the customer's risk. purchase of i 2 c components of cirrus logic, inc., or one of its sublicensed associated companies conveys a license under the phillips i 2 c patent rights to use those components in a standard i 2 c system. cirrus logic, cirrus, and the cirrus logic logo designs are trad emarks of cirrus logic, inc. all other brand and product names in this document may be trade- marks or service marks of their respective owners.
cs8415a 3 8.4 serial audio output port data format (06h) .................................................................... 21 8.5 interrupt 1 status (07h) (read only) ................................................................................ 22 8.6 interrupt 2 status (08h) (read only) ................................................................................ 23 8.7 interrupt 1 mask (09h) ...... ............................................................................................... .23 8.8 interrupt 1 mode msb (0ah) and interrupt 1 mode lsb(0bh).......................................... 23 8.9 interrupt 2 mask (0ch)................................ ..................................................................... .24 8.10 interrupt 2 mode msb (0dh) and interrupt 2 mode lsb(0eh) ....................................... 24 8.11 receiver channel status (0fh) (read only) .................................................................. 24 8.12 receiver error (10h) (read only)................................................................................... 25 8.13 receiver error mask (11h) ....................... ...................................................................... 26 8.14 channel status data buffer control (12h) ...................................................................... 26 8.15 user data buffer control (13h) ............. .......................................................................... 27 8.16 q-channel subcode bytes 0 to 9 (14h - 1dh) (read only) ........................................... 27 8.17 omck/rmck ratio (1eh) (r ead only).......................................................................... 27 8.18 c-bit or u-bit data buffer (20h - 37h) ............................................................................. 27 8.19 cs8415a i.d. and version register (7fh) (read only) ................................................. 27 9. pin description - software mode ............................................................................. 28 10. hardware mode ............................................................................................................ .30 10.1 serial audio port formats ....................... ...................................................................... 30 11. pin description - hardware mode .......................................................................... 31 12. applications ............................................................................................................ ...... 33 12.1 reset, power down and start-up .................................................................................. 33 12.2 id code and revision co de .......................................................................................... 33 12.3 power supply, grou nding, and pcb layout ................................................................... 33 13. package dimensions ................................................................................................... 34 14. appendix a: external aes3/spdif/iec60958 receiver components ............. 36 14.1 aes3 receiver external components ........................................................................... 36 14.2 isolating transformer requirements ............................................................................. 36 15. appendix b: channel status and user data buffer management ........... 38 15.1 aes3 channel status (c) bit management ................................................................... 38 15.2 accessing the e buffer ... ................................................................................................ 38 15.2.1 reserving the first 5 bytes in the e buffer ......................................................... 38 15.2.2 serial copy management system (s cms) ....................................................... 39 15.2.3 channel status data e buffer access .............................................................. 39 15.2.3.1 one byte mode ........................ ......................................................... 39 15.2.3.2 two byte mode .................... ............................................................. 39 15.3 aes3 user (u) bit management .................................................................................... 39 16. appendix c: pll filter .................................................................................................. 4 0 16.1 general .................................................................................................................. ........ 40 16.2 external filter component s ........................................................................................... 41 16.2.1 general ............................................................................................................. 41 16.2.2 capacitor selection . .......................................................................................... 41 16.2.3 circuit board layout ......................................................................................... 41 16.2.4 component value sele ction ............................................................................. 42 16.2.5 jitter attenuation ..... .......................................................................................... 42
cs8415a 4 list of tables table 1. control register map summary ............ .......................................................................... 19 table 2. equivalent software mode bit definitions ....................................................................... 30 table 3. hardware mode start-up options.................................................................................... 30 table 4. external pll component values .................................................................................... 42 list of figures figure 1. audio port master mode timing........... ............................................................................ 7 figure 2. audio port slave mode and data inpu t timing ................................................................ 7 figure 3. spi mode timing............................ .......................................................................... ........ 8 figure 4. i2c mode timing ...................................................................................................... ......... 9 figure 5. recommended connection diagram for software mode............................................... 10 figure 6. serial audio output example formats. .......................................................................... 13 figure 7. aes3 receiver timing for c & u pin output data .......................................................... 16 figure 8. control port timing in spi mode.................................................................................... 17 figure 9. control port timing in i2c mode.................................................................................... 18 figure 9. hardware mode........................................................................................................ ...... 30 figure 10. professional input circuit .......................................................................................... ... 36 figure 11. transformerless profe ssional input circuit .................................................................. 36 figure 12. consumer input circuit ................... ........................................................................... .. 37 figure 13. s/pdif mux input circuit .................. .......................................................................... 37 figure 14. ttl/cmos input circuit.............................................................................................. .37 figure 15. channel status data buffer structure.......................................................................... 38 figure 16. flowchart for readin g the e buffer .............................................................................. 38 figure 17. pll block diagram ... ................................................................................................ ... 40 figure 18. recommended layout example ............ ...................................................................... 41 figure 19. jitter attenuation ch aracteristics of pll with fs=32 to 96 khz filter components ..... 42
cs8415a 5 1. characteristics and specifications (all min/max characteristics and specifications are guarante ed over the specified operat ing conditions. typical per- formance characteristics and specifications are derived from measurements taken at nominal supply voltages and t a = 25 c.) specified operat ing conditions (agnd, dgnd = 0 v, all voltages with respect to 0v) notes: 1. i 2 c protocol is supported only in 5v mode. absolute maximum ratings (agnd, dgnd = 0 v; all voltages with respect to 0v. operation beyond these limits may result in permanent damage to th e device. normal operation is not guaranteed at these extremes.) notes: 2. transient currents of up to 100ma will not cause scr latch-up. parameter symbol min typ max units power supply voltage (note 1) va+ vl+ 4.5 2.85 5.0 3.3 or 5.0 5.5 5.5 v v ambient operating temperature: ?-cs? & ?-cz? ?-is? & ?-iz? t a -10 -40 - - +70 +85 c parameter symbol min max units power supply voltage vl+,va+ - 6.0 v input current, any pin ex cept supplies (note 2) i in -10ma input voltage v in -0.3 (vl+) + 0.3 v ambient operating temperature (power applied) t a -55 125 c storage temperature t stg -65 150 c
cs8415a 6 dc electrical characteristics (agnd = dgnd = 0 v; all voltages with respect to 0 v.) notes: 3. power down mode is defined as rst = lo with all clocks and data lines held static. 4. normal operation is defined as rst = hi. digital input characteristics digital interface specifications (agnd = dgnd = 0 v; all voltages with respect to 0 v.) notes: 5. at 5v mode, v il = 0.8v (max), at 3v mode, v il =0.4v (max). switching characteristics (inputs: logic 0 = 0v, logic 1 = vl+; c l = 20 pf) notes: 6. cycle-to-cycle using 32-96khz external pll filter components. parameters symbol min typ max units power-down mode (note 3) supply current in power down va+ vl+ = 3 v vl+ = 5 v - - - 20 60 60 - - - a a a normal operation (note 4) supply current at 48 khz frame rate va+ vl+ = 3 v vl+ = 5 v - - - 6.3 30.1 46.5 - - - ma ma ma supply current at 96 khz frame rate va+ vl+ = 3 v vl+ = 5 v - - - 6.6 44.8 76.6 - - - ma ma ma parameters symbol min typ max units input leakage current i in -110 a differential input voltage, rxp0 to rxn0 v th -200- mv parameters symbol min max units high-level output voltage (i oh = -3.2 ma) v oh (vl+) - 1.0 - v low-level output voltage (i oh = 3.2 ma) v ol -0.4v high-level input voltage, except rx n v ih 2.0 (vl+) + 0.3 v low-level input voltage, except rx n (note 5) v il -0.3 0.4/0.8 v parameter symbol min typ max units rst pin low pulse width 200 - - s pll clock recovery sample rate range 8.0 - 108.0 khz rmck output jitter - 200 - ps rms rmck output duty cycle (note 6) 40 50 60 %
cs8415a 7 switching characteristics - serial audio ports (inputs: logic 0 = 0 v, logic 1 = vl+; c l = 20 pf) notes: 7. the active edges of osclk are programmable. 8. the polarity olrck is programmable. 9. no more than 128 sclk per frame. 10. this delay is to prevent the previous osclk edge from being interpreted as the first one after olrck has changed. 11. this setup time ensures that this osclk edge is interpreted as the first one after olrck has changed. parameter symbol min typ max units osclk active edge to sdout output valid (note 7) t dpd - - 20 ns master mode rmck to osclk active edge delay (note 7) t smd 0 - 10 ns rmck to olrck delay (note 8) t lmd 0 - 10 ns osclk and olrck duty cycle - 50 - % slave mode osclk period (note 9) t sckw 36 - - ns osclk input low width t sckl 14 - - ns osclk input high width t sckh 14 - - ns osclk active edge to olrck edge (note 7,8,10) t lrckd 20 - - ns olrck edge setup before osclk active edge (note 7,8,11) t lrcks 20 - - ns t smd t lm d hardware mode software mode osclk (output) olrck (output) rmck (output) rmck (output) sckh sckl sckw t t t t dpd sdout (input) (input) lrcks t lrckd t osclk olrck figure 1. audio port master mode timing figure 2. audio port slave mode and data input timing
cs8415a 8 switching characteristics - control port - spi mode (inputs: logic 0 = 0 v, logic 1 = vl+; c l = 20 pf) notes: 12. if fs is lower than 46.875 khz, the maximum ccl k frequency should be less than 128 fs. this is dictated by the timing requirements necessary to access the channel status and user bit buffer memory. access to the control register file can be carried out at the full 6 mhz rate. the minimum allowable input sample rate is 8 khz, so choosing cclk to be less than or equal to 1.024 mhz should be safe for all possible conditions. 13. data must be held for sufficient time to bridge the transition time of cclk. 14. for f sck <1 mhz. parameter symbol min typ max units cclk clock frequency (note 12) f sck 0-6.0mhz cs high time between transmissions t csh 1.0 - - s cs falling to cclk edge t css 20 - - ns cclk low time t scl 66 - - ns cclk high time t sch 66 - - ns cdin to cclk rising setup time t dsu 40 - - ns cclk rising to data hold time (note 13) t dh 15 - - ns cclk falling to cdout stable t pd - - 50 ns rise time of cdout t r1 - - 25 ns fall time of cdout t f1 - - 25 ns rise time of cclk and cdin (note 14) t r2 - - 100 ns fall time of cclk and cdin (note 14) t f2 - - 100 ns t r2 t f2 t dsu t dh t sch t scl cs cclk cdin t css t pd cdout t csh figure 3. spi mode timing
cs8415a 9 switching characteristics - control port - i 2 c mode (note 15, inputs: logic 0 = 0 v, logic 1 = vl+; c l = 20 pf) notes: 15. i 2 c protocol is supported only in 5v mode. 16. data must be held for sufficient time to bridge the 25 ns transition time of scl. parameter symbol min typ max units scl clock frequency f scl - - 100 khz bus free time between transmissions t buf 4.7 - - s start condition hold time (p rior to first clock pulse) t hdst 4.0 - - s clock low time t low 4.7 - - s clock high time t high 4.0 - - s setup time for repeated start condition t sust 4.7 - - s sda hold time from scl falling (note 16) t hdd 0- - s sda setup time to scl rising t sud 250 - - ns rise time of both sda and scl lines t r - - 25 ns fall time of both sda and scl lines t f - - 25 ns setup time for stop condition t susp 4.7 - - s t buf t hdst t hdst t low t r t f t hdd t high t sud t sust t susp stop start start stop repeated sda scl figure 4. i 2 c mode timing
cs8415a 10 2. typical connection diagram rxp0 rxn0 aes3/ spdif sources clock control rmck hardware control rst rerr emph 3-wire serial audio input device olrck osclk sdout sda/cdout ad0/cs scl/cclk ad1/cdin u int va+ v l + ferrite * bead +5v analog supply * digital supply 0.1 f 0.1 f * a separate analog supply is only necessary in applications where rmck is used for a jitter sensitive task. for applications where rmck is not used for a jitter sensitive task, connect va+ to vd+ via a ferrite bead. keep the decoupling capacitor between va+ and agnd. dgnd filt agnd rfilt cfilt crip h/s dgnd2 rxp1 rxp2 rxp3 rxp4 rxp5 rxp6 cs8415a +3.3v or +5v ** ** please see section 5.1 "7:1 s/pdif input multiplexer" and appendix a for typical input configurations and recommended input circuits. a2 d / microcontroller figure 5. recommended conn ection diagram for software mode
cs8415a 11 3. general description the cs8415a is a monolithic cmos device which receives and decodes audio data according to the aes3, iec60958, s/pdif, and eiaj cp1201 inter- face standards. input data is either differential or single-ended. a low jitter clock is recovered from the incoming data using a pll. the decoded audio data is output through a configurable, 3-wire output port. the channel status and user data are assembled in block sized buffers and may be accessed through an spi or i 2 c microcontroller port. for systems with no microcontroller, a stand alone mode allows direct access to channel status and user data out- put pins. target applications include avr, cd-r, dat, dvd, multimedia speakers, md and vtr equip- ment, mixing consoles, di gital audio transmission and receiving equipment, high quality d/a and a/d converters, effects processors, set-top tv boxes, and computer audio systems. figure 5 shows the supply and external connec- tions to the cs8415a, when configured for opera- tion with a microcontroller. 3.1 aes3 and s/pdif standards documents this data sheet assumes t hat the user is familiar with the aes3 and s/pdif data formats. it is advis- able to have current copies of the aes3 and iec60958 specifications on hand for easy refer- ence. the latest aes3 standard is available from the au- dio engineering society or ansi at www.aes.org or www.ansi.org. obtain the latest iec60958 stan- dard from ansi or from the international electro- technical commission at www.iec.ch. the latest eiaj cp-1201 standard is available from the jap- anese electronics bureau. cirrus logic application note 22: overview of dig- ital audio interface data structures contains a use- ful tutorial on digital audio specifications, but it should not be considered a substitute for the stan- dards. the paper an understanding and implementation of the scms serial copy management system for digital audio transmission , by clifton sanchez, is an excellent tutorial on scms. it is available from the aes as preprint 3518.
cs8415a 12 4. serial audio output port a 3-wire serial audio output port is provided. the port can be adjusted to suit the attached device setting the control registers. the following param- eters are adjustable: master or slave, serial clock frequency, audio data resolution, left or right justifi- cation of the data relative to left/right clock, option- al one-bit cell delay of the first data bit, the polarity of the bit clock and the polarity of the left/right clock. by setting the appropriate control bits, many formats are possible. figure 6 shows a selection of common output for- mats, along with the control bit settings. it should be noted that in right justified mode, the serial au- dio output data is "msb extended". this means that in a sub-frame where the msb of the data is '1', all bits preceding the msb in the sub-frame will also be '1'. conversely, in a sub-frame where the msb of the data is '0', all bits preceding the msb in the sub-frame will also be '0'. a special aes3 direct output format is included, which allows the serial output port access to the v, u, and c bits embedded in the serial audio data stream. the p bit is replaced by a z bit that marks the start of each block. the received channel sta- tus block start signal is only available in hardware mode, as the rcbl pin. in master mode, the left/right clock and the serial bit clock are outputs, derived from the recovered rmck clock. in slave mode, the left/right clock and the serial bit clock are inputs. the left/right clock must be synchronous to the appropriate master clock, but the serial bit clock can be asynchronous and discontinuous if required. by appropriate phasing of the left/right clock and control of the se- rial clocks, multiple cs8415a?s can share one se- rial port. the left/right clock should be continuous, but the duty cycle can be less than the specified typical value of 50% if enough serial clocks are present in each phase to clock all the data bits. when in slave mode, the serial audio output port must not be set for right-justified data. when using the serial audio output port in slave mode with an olrck input which is asynchronous to the incom- ing aes3 data, then an interrupt bit(oslip) is pro- vided to indicate when repeated or dropped samples occur.the cs8415a allows immediate mute of the serial audio output port audio data by the mutesao bit of cont rol register 1.
cs8415a 13 msb lsb left right msb i s (out) olrck osclk sdout olrck osclk sdout 2 left justified (out) msb lsb olrck osclk sdout msb lsb msb left right aes3 direct (out) vz uc lsb lsb vz uc right justified (out) olrck osclk sdout msb lsb msb lsb msb left right msb lsb left right lsb msb lsb msb extended msb extended msb ex figure 6. serial audio output example formats x = don?t care to match format, but does need to be set to the desired setting * see serial output data format r egister bit descriptions for an expl anation of the meaning of each bit soms* sosf* sores[1:0]* soj ust* sodel* sospol* solrpol* left justified x x xx 0 0 0 0 i 2 s xxxx0101 right justified 1 x xx 1 0 0 0 aes3 direct x x 11 0 0 0 0
cs8415a 14 5. aes3 receiver the cs8415a includes an aes3 digital audio re- ceiver. a comprehensive buffering scheme pro- vides read access to the channel status and user data. this buffering scheme is described in appen- dix b. the aes3 receiver ac cepts and decodes audio and digital data accord ing to the aes3, iec60958 (s/pdif), and eiaj cp-1201 interface standards. the receiver consists of a differential input stage, driven through pins rxp0 and rxn0, a pll based clock recovery circuit, and a decoder which sepa- rates the audio data from the channel status and user data. external components are used to terminate and isolate the incoming data cables from the cs8415a. these components are detailed in ap- pendix a. 5.1 7:1 s/pdif input multiplexer the cs8415a employs a 7:1 s/pdif input multi- plexer to accommodate up to seven channels of in- put digital audio data. digital audio data is single- ended and input through the rxp0-6 pins. when any portion of the multiplexer is implemented, un- used rxp pins should be tied to ground, and rxn0 must be ac-coupled to ground. the multi- plexer select line control is accessed through bits mux2:0 in the control 2 register. the multiplexer defaults to rxp0. therefore, the default configura- tion is for a differential signal to be input through rxp0 & rxn0. please see appendix a for recom- mended input circuits. 5.2 omck system clock mode a special clock switching mode is available that al- lows the clock that is input through the omck pin to be output through the rmck pin. this feature is controlled by the swclk bit in register 1 of the control registers. when the pll loses lock, the fre- quency of the vco drops to 300 khz. the clock switching mode allows the clock input through omck to be used as a clock in the system without any disruption when the pll loses lock, for exam- ple, when the input is removed from the receiver. when swclk is enabled and this mode is imple- mented, rmck is an output and is not bi-direction- al. this clock switching is done glitch free. please note that internal circuitry associated with rmck is not driven by omck. this means that osclk and olrck continue to be derived from the pll and are not usable in this mode. this function is avail- able only in software mode. 5.3 pll, jitter attenuation, and varispeed please see appendix c for general description of the pll, selection of recommended pll filter com- ponents, and layout considerations. figure 5 shows the recommended configuration of the two capacitors and one resistor that comprise the pll filter. 5.4 error reporting and hold function while decoding the incoming aes3 data stream, the cs8415a can identify several kinds of error, in- dicated in the receiver error register. the un- lock bit indicates whether the pll is locked to the incoming aes3 data. the v bit reflects the cur- rent validity bit status. the conf (confidence) bit is the logical or of bip and unlock. the bip (bi- phase) error bit indicates an error in incoming bi- phase coding. the par (parity) bit indicates a re- ceived parity error. the error bits are "sticky": they are set on the first occurrence of the associated error and will remain set until the user reads the register through the control port. this enables the register to log all un- masked errors that occurred since the last time the register was read. the receiver error mask register allows masking of individual errors. the bits in this register serve as masks for the corresponding bits of the receiv- er error register. if a mask bit is set to 1, the error is unmasked, which implies the following: its occur- rence will be reported in the receiver error register, induce a pulse on rerr, invoke the occurrence of a rerr interrupt, and affect the current audio sample according to the status of the hold bits. the hold bits allow a choi ce of holding the previ- ous sample, replacing the current sample with zero (mute), or not changing the current audio sample. if a mask bit is set to 0, the error is masked, which implies the following: its occurrence will not be re- ported in the receiver error register, will not induce a pulse on rerr or generate a rerr interrupt, and will not affect the current audio sample. the
cs8415a 15 qcrc and ccrc errors do not affect the current audio sample, even if unmasked. 5.5 channel status data handling the first 2 bytes of the channel status block are decoded into the receiver channel status regis- ter. the setting of the chs bit in the channel sta- tus data buffer control register determines whether the channel status decodes are from the a channel (chs = 0) or b channel (chs = 1). the pro (professional) bit is extracted directly. for consumer data, the copy (copyright) bit is ex- tracted, and the category code and l bits are de- coded to determine scms status, indicated by the orig (original) bit. if the category code is set to general on the incoming aes3 stream, copyright will always be indicated even when the stream in- dicates no copyright. finally, the audio bit is ex- tracted and used to set an audio indicator, as described in the non-audio auto-detection section below. if 50/15 s pre-emphasis is detected, the state of the emph pin is adjusted accordingly. the encoded channel status bits which indicate sample word length are decoded according to aes3-1992 or iec 60958. audio data routed to the serial audio output port is unaffected by the word length settings; all 24 bits are passed on as re- ceived. appendix a describes the overall handling of channel status and user data. 5.6 user data handling the incoming user data is buffered in a user acces- sible buffer. received user data may also be out- put to the u pin under the control of a control register bit. depending on the clocking options se- lected, there may not be a clock available to qualify the u data output. figure 7 illustrates the timing. if the incoming user data bits have been encoded as q-channel subcode, the data is decoded and pre- sented in 10 consecutive re gister locations. an in- terrupt may be enabled to indicate the decoding of a new q-channel block, which may be read through the control port. 5.7 non-audio auto-detection an aes3 data stream may be used to convey non- audio data, thus it is important to know whether the incoming aes3 data stream is digital audio or not. this information is typica lly conveyed in channel status bit 1 (audio ), which is extracted automati- cally by the cs8415a. however, certain non-audio sources, such as ac-3 ? or mpeg encoders, may not adhere to this convention, and the bit may not be properly set. the cs8415a aes3 receiver can detect such non-audio data. this is accomplished by looking for a 96-bit sync code, consisting of 0x0000, 0x0000, 0x0000, 0x0000, 0xf872, and 0x4e1f. when the sync code is detected, an inter- nal autodetect signal will be asserted. if no ad- ditional sync codes are detected within the next 4096 frames, autodetect will be de-asserted until another sync code is detected. the audio bit in the receiver channel status register is the logi- cal or of autodetect and the received chan- nel status bit 1. if non-audio data is detected, the data is still processed exactly as if it were normal audio. it is up to the user to mute the outputs as re- quired. 5.8 mono mode operation an aes3 stream may be used in more than one way to transmit 96 khz sample rate data. one method is to double the frame rate of the current format. this results in a stereo signal with a sample rate of 96 khz, carried over a single twisted pair cable. an alternate method is implemented using the 2 sub-frames in a 48 khz frame rate aes3 sig- nal to carry consecutive samples of a mono signal, resulting in a 96 khz sample rate stream. this al- lows older equipment, whose aes3 transmitters and receivers are not rated for 96 khz frame rate operation, to handle 96 khz sample rate informa- tion. in this ?mono mode?, 2 aes3 cables are need- ed for stereo data transfer. the cs8415a offers mono mode operation, controlled through the mmr control register bit. the receiver mono mode effectively doubles fs compared to the input frame rate. the clock output on the rmck pin tracks fs, and so is doubled in frequency compared to stereo mode. the receiver will run at a frame rate of fs/2, and the serial audio output port will run at fs. sub-frame a data will be
cs8415a 16 routed to both the left and right data fields on sd- out. similarly, sub-frame b data will be routed to both the left and right data fields of the next word clock cycle of sdout. using mono mode is only necessary if the serial audio output port must run at 96 khz. if the cs8415a is kept in normal stereo mode, and re- ceives aes3 data arranged in mono mode, then the serial audio output port will run at 48 khz, with left and right data fields representing consecutive audio samples. rcbl out vlrck c, u ouput rcbl and c output are only available in hardware mode. rcbl goes high 2 frames after receipt of a z pre-amble, and is high for 16 frames. vlrck is a virtual word clock, which may not exist, but is used to illustrate the cu timing. vlrck duty cycle is 50%. vlrck frequency is always equal to the incoming frame rate. if the serial audio output port is in master mode, vlrck = olrck. if the serial audio output port is in slave mode, then vlrck needs to be externally created, if required. c, u transitions are aligned within 1% of vlrck period to vlrck edges figure 7. aes3 receiver timing for c & u pin output data
cs8415a 17 6. control port description and timing the control port is used to access the registers, al- lowing the cs8415a to be configured for the de- sired operational modes and formats. in addition, channel status and user data may be read through the control port. the operation of the con- trol port may be completely asynchronous with re- spect to the audio sample rates. however, to avoid potential interference problems, the control port pins should remain static if no operation is re- quired. the control port has 2 modes: spi and i 2 c, with the cs8415a acting as a slave device. spi mode is selected if there is a high to low transition on the ad0/cs pin, after the rst pin has been brought high. i 2 c mode is selected by connecting the ad0/cs pin to vl+ or dgnd, thereby permanently selecting the desired ad0 bit address state. 6.1 spi mode in spi mode, cs is the cs8415a chip select sig- nal, cclk is the control port bit clock (input into the cs8415a from the microcontroller), cdin is the in- put data line from the microcontroller, cdout is the output data line to the microcontroller. data is clocked in on the rising edge of cclk and out on the falling edge. figure 8 shows the operation of the control port in spi mode. to write to a register, bring cs low. the first seven bits on cdin form the chip address and must be 0010000. the eighth bit is a read/write in- dicator (r/w ), which should be low to write. the next eight bits form the memory address pointer (map), which is set to the address of the register that is to be updated. the next eight bits are the data which will be placed into the register designat- ed by the map. during writes, the cdout output stays in the hi-z state. it may be externally pulled high or low with a 47 k ? resistor, if desired. there is a map auto increment capability, enabled by the incr bit in the map register. if incr is a ze- ro, the map will stay constant for successive read or writes. if incr is set to a 1, the map will autoin- crement after each byte is read or written, allowing block reads or writes of successive registers. to read a register, the map has to be set to the correct address by execut ing a partial write cycle which finishes (cs high) immediately after the map byte. the map auto increment bit (incr) may be set or not, as desired. to begin a read, bring cs low, send out the chip address and set the read/write bit (r/w ) high. the next falling edge of cclk will clock out the msb of the addressed register (cdout will leave the high impedance state). if the map auto increment bit is set to 1, the data for successive registers will appear consecu- tively. 6.2 i 2 c mode in i 2 c mode, sda is a bidirectional data line. data is clocked into and out of the part by the clock, map msb lsb data byte 1 byte n r/w r/w address chip address chip cdin cclk cs cdout msb lsb msb lsb 0010000 0010000 map = memory address pointer, 8 bits, msb first high impedance figure 8. control po rt timing in spi mode
cs8415a 18 scl, with the clock to data relationship as shown in figure 9. there is no cs pin. each individual cs8415a is given a unique address. pins ad0 and ad1 form the two least significant bits of the chip address and should be connected to vl+ or dgnd as desired. the emph pin is used to set the ad2 bit by connecting a resistor from the emph pin to vl+ or to dgnd. the state of the pin is sensed while the cs8415a is being reset. the upper 4 bits of the 7-bit address field are fixed at 0010. to com- municate with a cs8415a, the chip address field, which is the first byte sent to the cs8415a, should match 0010 followed by the settings of the emph , ad1, and ad0. the eighth bit of the address is the r/w bit. if the operation is a write, the next byte is the memory address pointer (map) which selects the register to be read or written. if the operation is a read, the contents of the register pointed to by the map will be output. setting the auto increment bit in map allows successive reads or writes of consecutive registers. each byte is separated by an acknowledge bit. the ack bit is output from the cs8415a after each input byte is read, and is input to the cs8415a from the microcontroller after each transmitted byte. i 2 c mode is supported only with vl+ in 5v mode. 6.3 interrupts the cs8415a has a comprehensive interrupt ca- pability. the int output pin is intended to drive the interrupt input pin on the host microcontroller. the int pin may be set to be active low, active high or active low with no active pull-up transistor. this last mode is used for active low, wired-or hook-ups, with multiple peripherals connected to the micro- controller interrupt input pin. many conditions can cause an interrupt, as listed in the interrupt status register descriptions. each source may be masked off through mask register bits. in addition, each source may be set to rising edge, falling edge, or level sensitive. combined with the option of level sensitive or edge sensitive modes within the microcontroller, many different configurations are possible, depending on the needs of the equipment designer. sda scl 0010 ad2-0 r/w start ack data7-0 ack data7-0 ack stop note 2 note 1 note 3 notes: 1. ad2 is derived from a resistor attached to the emph pin. ad1 and ad0 are determined by the state of the corresponding pins. 2. if operation is a write, this byte c ontains the memory address pointer, map. 3. if operation is a read, the last bit of the read should be nack (high). figure 9. control port timing in i 2 c mode
cs8415a 19 7. control port register summary 7.1 memory address pointer (map) incr - auto increment address control bit default = ?0? 0 - disabled 1 - enabled map6:map0 - register address note: reserved registers must not be written to during no rmal operation. some reserved registers are used for test modes, which can completely alte r the normal operation of the cs8415a. addr (hex) function 7 6 5 4 3 2 1 0 01 control 1 swclk 0 mutesao 0 0 int1 int0 0 02 control 2 0 hold1 hold0 rmckf mmr mux2 mux1 mux0 04 clock source control 0 run 0 0 0 0 0 1 06 serial output format soms sosf sores1 sores0 sojust sodel sospol solrpol 07 interrupt 1 status 0 oslip 0 0 0 detc 0 rerr 08 interrupt 2 status 0 0 0 0 detu 0 qch 0 09 interrupt 1 mask 0 oslipm 0 0 0 detcm 0 rerrm 0a interrupt 1 mode (msb) 0 oslip1 0 0 0 detc1 0 rerr1 0b interrupt 1 mode (lsb) 0 oslip0 0 0 0 detc0 0 rerr0 0c interrupt 2 mask 0 0 0 0 detum 0 qchm 0 0d interrupt 2 mode (msb) 0 0 0 0 detu1 0 qch1 0 0e interrupt 2 mode (lsb) 0 0 0 0 detu0 0 qch0 0 0f receiver cs data aux3 aux2 aux1 aux0 pro audio copy orig 10 receiver errors 0 qcrc ccrc unlock v conf bip par 11 receiver error mask 0 qcrcm ccrcm unlockm vm confm bipm parm 12 cs data buffer control 0 0 bsel cbmr detci 0 cam chs 13 u data buffer control 0 0 0 0 0 0 detui 0 14-1d q sub-code data 1e omck/rmck ratio orr7 orr6 orr5 orr4 orr3 orr2 orr1 orr0 20-37 c or u data buffer 7f id and version id3 id2 id1 id0 ver3 ver2 ver1 ver0 table 1. control register map summary 7 6 543210 incr map6 map5 map4 map3 map2 map1 map0
cs8415a 20 8. control port register bit definitions 8.1 control 1(01h) swclk - controls output of omck on rmck when pll loses lock default = ?0? 0 - rmck default function 1 - omck output on rmck pin mutesao - mute control for the serial audio output port default = ?0? 0 - disabled 1 - enabled int1:0 - interrupt output pin (int) control default = ?00? 00 - active high; high output indicates interrupt condition has occurred 01 - active low, low output indicates an interrupt condition has occurred 10 - open drain, active low. requires an external pull-up resistor on the int pin. 11 - reserved 8.2 control 2 (02h) hold1:0 - determine how received audio sample is affected when a receiver error occurs default = ?00? 00 - hold the last valid audio sample 01 - replace the current audio sample with 00 (mute) 10 - do not change the received audio sample 11 - reserved rmckf - select recovered master clock output pin frequency. default = ?0? 0 - rmck is equal to 256 * fs 1 - rmck is equal to 128 * fs mmr - select aes3 receiver mono or stereo operation default = ?0? 0 - normal stereo operation 1 - a and b subframes treated as consec utive samples of one channel of data. data is duplicated to both left and right parallel outputs of the aes receiver block. the sample rate (fs) is doubled compared to mmr=0 7 6 543210 swclk 0 mutesao 0 0 int1 int0 0 7 6 543210 0 hold1 hold0 rmckf mmr mux2 mux1 mux0
cs8415a 21 mux2:0 - 7:1 s/pdif input multiplexer select line control default = ?000? 000 - rxp0 001 - rxp1 010 - rxp2 011 - rxp3 100 - rxp4 101 - rxp5 110 - rxp6 111 - reserved 8.3 clock source control (04h) this register configures the clock sources of various bloc ks. in conjunction with the data flow control register, var- ious receiver/transmitter/transceiver modes may be selected. run - controls the internal clocks , allowing the cs8415a to be placed in a ?powered down?, low current consumption, state. default = ?0? 0 - internal clocks are stopped. internal state mach ines are reset. the fully static control port is operational, allowing registers to be read or changed. reading and writing the u and c data buffers is not possible. power consumption is low. 1 - normal part operation. this bit must be writ ten to the 1 state to allow the cs8415a to begin operation. all input clocks should be stable in frequency and phas e when run is set to 1. 8.4 serial audio output port data format (06h) soms - master/slave mode selector default = ?0? 0 - serial audio output port is in slave mode 1 - serial audio output port is in master mode sosf - osclk frequency (for master mode) default = ?0? 0 - 64*fs 1 - 128*fs sores1:0 - resolution of the output data on sdout default = ?00? 00 - 24-bit resolution 01 - 20-bit resolution 10 - 16-bit resolution 11 - direct copy of the received nrz data from the aes3 receiver (includi ng c, u, and v bits, the time slot normally occupied by the p bit is used to indicate the locati on of the block start, 7 6 543210 0run000000 7 6 543210 soms sosf sores1 sores0 sojust sodel sospol solrpol
cs8415a 22 sdout pin only, serial audio outp ut port clock must be derive d from the aes3 receiver recov- ered clock) sojust - justification of sdout data relative to olrck default = ?0? 0 - left-justified 1 - right-justified (master mode only) sodel - delay of sdout data relative to olrck, for left-justified data formats default = ?0? 0 - msb of sdout data occurs in the first osclk period after the olrck edge 1 - msb of sdout data occurs in the second osclk period after the olrck edge sospol - osclk clock polarity default = ?0? 0 - sdout sampled on rising edges of osclk 1 - sdout sampled on falling edges of osclk solrpol - olrck clock polarity default = ?0? 0 - sdout data is for the left channel when olrck is high 1 - sdout data is for the right channel when olrck is high 8.5 interrupt 1 status (07h) (read only) for all bits in this register, a ?1? means the associated interrupt condition has o ccurred at least once since the register was last read. a ?0? means the associated interrupt conditi on has not occurred since the last reading of the register. reading the register resets all bits to 0, unless the interrupt mode is set to le vel and the interrupt source is still true. status bits that are masked off in the a ssociated mask register will always be ?0? in this register. this register defaults to 00h. oslip - serial audio output port data slip interrupt when the serial audio output port is in slave mode, and olrck is asynchronous to the port data source, this bit will go high every time a data sample is dropped or repeated. detc - d to e c-buffer transfer interrupt. the source for this bit is true during the d to e buffer transfer in the c bit buffer management process. rerr - a receiver error has occurred. the receiver error register may be read to determine the nature of the error which caused the interrupt. 7 6 543210 0 oslip 0 0 0 detc 0 rerr
cs8415a 23 8.6 interrupt 2 status (08h) (read only) for all bits in this register, a ?1? means the associated interrupt condition has o ccurred at least once since the register was last read. a ?0? means the associated interrupt conditi on has not occurred since the last reading of the register. reading the register resets all bits to 0, unless the interrupt mode is set to le vel and the interrupt source is still true. status bits that are masked off in the a ssociated mask register will always be ?0? in this register. this register defaults to 00h. detu - d to e u-buffer transfer interrupt. (block mode only) the source of this bit is true during the d to e buffer transfer in th e u bit buffer management process. qch - a new block of q-subcode da ta is available for reading. the data must be comple tely read within 588 aes3 frames af ter the interrupt occurs to avoid corruption of the da ta by the next block. 8.7 interrupt 1 mask (09h) the bits of this register serve as a mask for the interrupt 1 register. if a mask bit is set to 1, the error is unmasked, meaning that its occurrence will af fect the int pin and t he status register. if a mask bit is set to 0, the error is masked, meaning that its occurrence will not affect the int pin or the status regi ster. the bit positions align with the corre- sponding bits in interrupt 1 regist er. this register defaults to 00h. 8.8 interrupt 1 mode msb (0ah) and interrupt 1 mode lsb(0bh) the two interrupt mode registers form a 2-bit code for each interrupt register 1 function. there are three ways to set the int pin active in accordance with the interrupt co ndition. in the rising edge ac tive mode, the int pin be- comes active on the arrival of the interrupt condition. in the falling edge active mode, the int pin becomes active on the removal of the interrupt condition. in level active mode, the int interrupt pin becomes active during the in- terrupt condition. be aware that the active level(actice high or low) only depends on t he int[1:0] bits. these regis- ters default to 00. 00 - rising edge active 01 - falling edge active 10 - level active 11 - reserved 8.9 interrupt 2 mask (0ch) the bits of this register serve as a mask for the interrupt 2 register. if a mask bit is set to 1, the error is unmasked, meaning that its occurrence will af fect the int pin and t he status register. if a mask bit is set to 0, the error is masked, meaning that its occurrence will not affect the int pin or the status regi ster. the bit positions align with the corre- 7 6 543210 0 0 0 0 detu 0 qch 0 7 6 543210 0 oslipm 0 0 0 detcm 0 rerrm 7 6 543210 0 oslip1 0 0 0 detc1 0 rerr1 0 oslip0 0 0 0 detc0 0 rerr0 7 6 543210 0000detum0qchm0
cs8415a 24 sponding bits in interrupt 2 regist er. this register defaults to 00h. 8.10 interrupt 2 mode msb (0dh) and interrupt 2 mode lsb(0eh) the two interrupt mode registers form a 2-bit code for each interrupt register 1 function. there are three ways to set the int pin active in accordance with the interrupt co ndition. in the rising edge ac tive mode, the int pin be- comes active on the arrival of the interrupt condition. in the falling edge active mode, the int pin becomes active on the removal of the interrupt condition. in level active mode, the int interrupt pin becomes active during the in- terrupt condition. be aware that the active level(actice high or low) only depends on t he int[1:0] bits. these regis- ters default to 00. 00 - rising edge active 01 - falling edge active 10 - level active 11 - reserved 8.11 receiver channel status (0fh) (read only) the bits in this register can be associated with either channel a or b of the received data. the desired channel is selected with the chs bit of the channe l status data buffer control register. aux3:0 - incoming auxiliary data field width, as indicated by the incoming channel status bits, de- coded according to iec60958 and aes3. 0000 - auxiliary da ta is not present 0001 - auxiliary data is 1 bit long 0010 - auxiliary da ta is 2 bits long 0011 - auxiliary da ta is 3 bits long 0100 - auxiliary data is 4 bits long 0101 - auxiliary da ta is 5 bits long 0110 - auxiliary da ta is 6 bits long 0111 - auxiliary da ta is 7 bits long 1000 - auxiliary da ta is 8 bits long 1001 - 1111 reserved pro - channel status block format indicator 0 - received channel status block is in consumer format 1 - received channel status block is in professional format audio - audio indicator 0 - received data is linearly coded pcm audio 1 - received data is not linearly coded pcm audio copy - scms copyright indicator 0 - copyright asserted 1 - copyright not asserted if the category code is set to genera l in the incoming aes3 stream, copyrigh t will always be indicated by copy, even when the stream indicates no copyright. 7 6 543210 0 0 0 0 detu1 0 qch1 0 0 0 0 0 detu0 0 qch0 0 7 6 543210 aux3 aux2 aux1 aux0 pro audio copy orig
cs8415a 25 orig - scms generation indicator, decoded from the category code and the l bit. 0 - received data is 1st generation or higher 1 - received data is original note: copy and orig will both be se t to 1 if the incoming data is flagged as professional, or if the receiver is not in use. 8.12 receiver error (10h) (read only) this register contains the aes3 receiver and pll status bits. unmasked bits will go high on occurren ce of the error, and will stay high until the regist er is read. reading the regist er resets all bits to 0, unl ess the error source is still true. bits that are masked off in the receiver error mask regist er will always be 0 in this re gister. this register defaults to 00h. qcrc - q-subcode data crc error indicator. updated on q-subcode block boundaries 0 - no error 1 - error ccrc - channel status block cyclic redundancy ch eck bit. updated on cs block boundaries, valid in pro mode 0 - no error 1 - error unlock - pll lock status bit. updated on cs block boundaries. 0 - pll locked 1 - pll out of lock v - received aes3 validity bit stat us. updated on sub-frame boundaries. 0 - data is valid and is no rmally linear coded pcm audio 1 - data is invalid, or ma y be valid compressed audio conf - confidence bit. updated on sub-frame boundaries. 0 - no error 1 - confidence error. this is th e logical or of bip and unlock. bip - bi-phase error bit. updated on sub-frame boundaries. 0 - no error 1 - bi-phase error. this indicates an error in the received bi-phase coding. par - parity bit. updated on sub-frame boundaries. 0 - no error 1 - parity error 8.13 receiver error mask (11h) the bits in this register serve as masks for the correspondi ng bits of the receiver error register. if a mask bit is set to 1, the error is unmasked, meaning that its occurrence will appear in the receiver erro r register, will affect the rerr pin, will affect the rerr interrupt, and will affect the current audi o sample according to the status of the hold bit. if a mask bit is set to 0, the error is ma sked, meaning that it s occurrence will not appear in the receiver error register, 7 6 543210 0 qcrc ccrc unlock v conf bip par 7 6 543210 0 qcrcm ccrcm unlockm vm confm bipm parm
cs8415a 26 will not affect the rerr pin, will not a ffect the rerr interrupt, and will not af fect the current audio sample. the ccrc and qcrc bits behave differently fr om the other bits: they do not affect the current audio sample even when unmasked. this register defaults to 00h. 8.14 channel status data buffer control (12h) bsel - selects the data buffer register addresse s to contain user data or channel status data default = ?0? 0 - data buffer address space contains channel status data 1 - data buffer address space contains user data cbmr - control for the first 5 bytes of channel status ?e? buffer default = ?0? 0 - allow d to e buffer transfers to overwr ite the first 5 bytes of channel status data 1 - prevent d to e buffer transfers from over writing first 5 bytes of channel status data detci - d to e c-data buffer transfer inhibit bit. default = ?0? 0 - allow c-data d to e buffer transfers 1 - inhibit c-data d to e buffer transfers cam - c-data buffer control port access mode bit default = ?0? 0 - one byte mode 1 - two byte mode chs - channel select bit default = ?0? 0 - channel a information is displayed at the emph pin and in the receiver channel status reg- ister. channel a information is output during control port reads when cam is set to 0 (one byte mode) 1 - channel b information is displayed at the emph pin and in the receiver channel status reg- ister. channel b information is output during control port reads when cam is set to 0 (one byte mode) 8.15 user data buffer control (13h) detui - d to e u-data buffer transfer inhibit bit (valid in block mode only). default = ?0? 0 - allow u-data d to e buffer transfers 1 - inhibit u-data d to e buffer transfers 7 6 543210 0 0 bsel cbmr detci 0 cam chs 7 6 543210 000000detui0
cs8415a 27 8.16 q-channel subcode bytes 0 to 9 (14h - 1dh) (read only) the following 10 registers contain the decoded q-channel subcode data each byte is lsb first with respect to the 80 q-subc ode bits q[79:0]. thus bit 7 of address 14h is q[0] while bit 0 of address 0eh is q[7]. similarl y bit 0 of address 1dh corresponds to q[79]. 8.17 omck/rmck ratio (1eh) (read only) this register allows the calculation of the incoming sample rate by the host microcontroller from the equation orr=fso/fsi. the fso is determined by omck, whose frequency is assumed to be 256 fso. orr is represented as an unsigned 2-bit inte ger and a 6-bit fractional part. the value is mean- ingful only after the pll has reached lock. for ex ample, if the omck is 12.288mhz, fso would be 48khz (48khz = 12.288mhz/256). then if the input sample rate is also 48khz, you would get 1.0 from the orr register.(the value fr om the orr register is hexadecimal, so the actual value you will get is 40h). if f so /f si > 3 63 / 64 , orr will saturate at the value ffh. also, there is no hysteresis on orr. therefore a small am ount of jitter on either clock can cause the lsb orr[0] to oscillate. orr7:6 - integer part of the ratio (integer value=in teger(srr[7:6])) orr5:0 - fractional part of the ratio (fraction value=integer(srr[5:0])/64) 8.18 c-bit or u-bit data buffer (20h - 37h) either channel status data buffer e or user data bu ffer e is accessible through these register addresses. 8.19 cs8415a i.d. and version register (7fh) (read only) id3:0 - id code for the cs8415a. permanently set to 0100 ver3:0 - cs8415a revision level. revision a is coded as 0001 7 6 543210 control control control control address address address address track track track track track track track track index index index index index index index index minute minute minute minute minute minute minute minute second second second second second second second second frame frame frame frame frame frame frame frame zero zero zero zero zero zero zero zero abs minute abs minute abs minut e abs minute abs minute abs minute abs minute abs minute abs second abs second abs second abs secon d abs second abs second abs second abs second abs frame abs frame abs frame abs frame abs frame abs frame abs frame abs frame 7 6 543210 orr7 orr6 orr5 orr4 orr3 orr2 orr1 orr0 7 6 543210 id3 id2 id1 id0 ver3 ver2 ver1 ver0
cs8415a 28 9. pin description - software mode sda/cdout ad0/cs emph rxp0 rxn0 va+ agnd filt rst rmck rerr rxp1 28 27 26 25 *24 *23 *22 *21 20 19 *18 *17 *16 15 1 2 3*+ 4* 5* 6* 7* 8* 9* 10* 11* 12 13 14 scl/cclk ad1/cdin h/s v+ dgnd omck u int sdout olrck osclk * pins which remain the same function in all modes. + pins which require a pull up or pull down resistor to select the desired startup option. rxp2 rxp3 rxp4 rxp6 rxp5 l sda/cdout 1 serial control data i/o (i 2 c) / data out (spi) ( input/output ) - in i 2 c mode, sda is the control i/o data line. sda is open drain and requires an external pull-up resistor to vl+. in spi mode, cdout is the out- put data from the control po rt interface on the cs8415a ad0/cs 2 address bit 0 (i 2 c) / control port chip select (spi) ( input) - a falling edge on this pin puts the cs8415a into spi control port mode. with no falling edge, the cs8415a defaults to i 2 c mode. in i 2 c mode, ad0 is a chip address pin. in spi mode, cs is used to enable the cont rol port interface on the cs8415a emph 3 pre-emphasis ( output ) - emph is low when the incoming channel status data indicates 50/15 s pre- emphasis. emph is high when the channel status data indicates no pre-emphasis or indicates pre- emphasis other than 50/15 s. this is also a start-up option pin, and requires a 47 k ? resistor to either vl+ or dgnd, which determines the ad2 ad dress bit for the control port in i 2 c mode rxp0 rxn0 4 5 aes3/spdif receiver port ( input ) - differential line receiver inputs carrying aes3 data. rxp0 may be used as a single-ended input as part of 7:1 s/pdif input mux. if rxp0 is used in mux, rxn0 must be ac coupled to ground. rxp1 rxp2 rxp3 rxp4 rxp5 rxp6 12 13 14 15 25 26 additional aes3/spd if receiver port ( input ) - single-ended receiver inputs carrying aes3 or s/pdif digital data. these inputs, along with rxp0, comprise the 7:1 s/pdif input multiplexer and select line control is accessed using the mux2:0 bits in the co ntrol 2 register. please note that any unused inputs should be tied to ground. see appendix a for recommended input circuits. va+ 6 positive analog power ( input ) - positive supply for the analog section. nominally +5 v. this supply should be as quiet as possible since noise on this pin will directly affect the jitter performance of the recovered clock agnd 7 analog ground ( input ) - ground for the analog circuitry in the chip. agnd and dgnd should be con- nected to a common ground area under the chip. filt 8 pll loop filter ( output ) - an rc network should be connecte d between this pin and ground. see ?appendix c: pll filter? on page 40 for recommended schematic and component values. rst 9 reset ( input ) - when rst is low, the cs8415a enters a low po wer mode and all internal states are reset. on initial power up, rst must be held low until the power supply is stable, and all input clocks are stable in frequency and phase. this is particularly true in hardware mode with multiple cs8415a devices where synchronization between devices is important
cs8415a 29 rmck 10 input section recovered master clock ( output ) - input section recovered master clock output when pll is used. frequency defaults to 256x the sample rate (fs) and may be set to 128x. rerr 11 receiver error ( output ) - when high, indicates a problem with the operation of the aes3 receiver. the status of this pin is updated once per sub-frame of incoming aes3 data. conditions that can cause rerr to go high are: validity, parity error, bi- phase coding error, confidence, qcrc and ccrc errors, as well as loss of lock in the pll. each conditi on may be optionally masked fr om affecting the rerr pin using the receiver error mask regi ster. the rerr pin tracks the status of the unmasked errors: the pin goes high as soon as an unmasked error occurs and goes low immediately when all unmasked errors go away osclk 16 serial audio output bit clock ( input / output ) - serial bit clock for audio data on the sdout pin olrck 17 serial audio output left/right clock ( input / output ) - word rate clock for the audio data on the sdout pin. frequency will be the output sample rate (fs) sdout 18 serial audio output data ( output ) - audio data serial output pin int 19 interrupt ( output ) - indicates errors and key events during th e operation of the cs8415a. all bits affect- ing int may be unmasked through bits in the control re gisters. the condition(s) t hat initiated interrupt are readable through a control register. the polarity of th e int output, as well as selection of a standard or open drain output, is set through a control register. once set true, the int pin goes false only after the interrupt status registers have been read and the interrupt status bits have returned to zero u 20 user data ( output ) - outputs user data from the aes3 rece iver, see figure 7 for timing information omck 21 system clock ( input ) - when the omck system clock mode is enabled using the swclk bit in the control 1 register, the clock signal input on this pi n is output through rmck. omck serves as reference signal for omck/rmck ratio expressed in register 0x1e dgnd 22 digital ground ( input ) - ground for the digital circuitry in the chip. dgnd and agnd should be con- nected to a common ground area under the chip. vl+ 23 positive digital power ( input ) - positive supply for the digita l section. typically +3 to +5 v. h/s 24 hardware/software mode control ( input ) - determines the method of controlling the operation of the cs8415a, and the method of accessing cs and u data . in software mode, device control and cs and u data access is primarily through the control port, using a microcontroller. hardware mode provides an alternate mode of operation and access to the cs and u data through dedicated pins. this pin should be permanently tied to vl+ or dgnd ad1/cdin 27 address bit 1 (i 2 c) / serial control data in (spi) ( input ) - in i 2 c mode, ad1 is a chip address pin. in spi mode, cdin is the input data lin e for the control port interface scl/cclk 28 control port clock ( input ) - serial control interface clock and is used to clock control data bits into and out of the cs8415a. in i 2 c mode, scl requires an external pull-up resistor to vl+
cs8415a 30 10. hardware mode the cs8415a has a hardware mode which allows using the device without a microcontroller. hard- ware mode is selected by connecting the h/s pin to vl+. various pins change function in hardware mode, described in the hardware mode pin defini- tion section. hardware mode data flow is shown in figure 9. au- dio data is input through the aes3 receiver, and routed to the serial audio output port. the pro, copy, orig, emph , and audio channel status bits are output on pins. the decoded c and u bits are also output, clocked at both edges of olrck (master mode only, see figure 7).the current au- dio sample is passed unmod ified to the serial audio output port if the validity bit is high, or a parity, bi- phase, or pll lock error occurs. 10.1 serial audio port formats in hardware mode, only a limited number of alter- native serial audio port formats are available. table 2 defines the equivalent software mode bit settings for each format. start-up options are shown in table 3, and allow choice of the serial au- dio output port as a master or slave, and the serial audio port format. sosf sores1/0 sojust sodel sospol solrpol of1 - left justified 0 00 0 0 0 0 of2 - i 2 s 24-bit data 000 010 1 of3 - right justified, master mode only 0 00 1 0 0 0 of4 - direct aes3 data 0 11 0 0 0 0 table 2. equivalent software mode bit definitions sdout orig emph function lo - - serial output port is slave hi - - serial output port is master - lo lo left justified - lo hi i2s 24-bit data - hi lo right justified - hi hi direct aes3 data table 3. hardware mo de start-up options serial audio output aes3 rx & decoder c & u bit data buffer rxp rxn olrck osclk sdout rmck rerr copy orig emph rcbl pro audio chs h/s power supply pins (vd+, va+, dgnd, agnd) & the reset pin (rst) and the pll filter pin (filt) are omitted from this diagram. please refer to the typical connection diagram for hook-up details. vl+ nverr c u figure 9. hardware mode
cs8415a 31 11. pin description - hardware mode copy 1 copy channel status bit ( output ) - reflects the state of the copyright channel status bit in the incom- ing aes3 data stream. if the category code is set to general, copyright will be indicated whatever the state of the copyright bit. vl2+ vl+ vl3+ 2 23 27 positive digital power ( input ) - typically +3 to +5v. emph 3 pre-emphasis ( output ) - emph is low when the incoming channel status data indicates 50/15 s pre- emphasis. emph is high when the channel status data indicates no pre-emphasis or indicates pre- emphasis other than 50/15 s. this pin is also a start-up option which, along with orig, determines the serial port format. a 47 k ? resistor to either vl+ or dgnd is required. rxp0 rxn0 4 5 aes3/spdif receiver port ( input ) - differential line receiver inputs for the aes3 biphase encoded data. see appendix a for recommended circuits. va+ 6 positive analog power ( input ) - nominally +5 v. this supply should be as quiet as possible since noise on this pin will directly affect the ji tter performance of the recovered clock. agnd 7 analog ground ( input ) - ground for the analog circuitry in the chip. agnd and dgnd should be con- nected to a common ground area under the chip. filt 8 pll loop filter ( output ) - an rc network should be connecte d between this pin and ground. see ?appendix c: pll filter? on page 40 for recommended schematic and component values. rst 9 reset ( input ) - when rst is low, the cs8415a enters a low po wer mode and all internal states are reset. on initial power up, rst must be held low until the power supply is stable, and all input clocks are stable in frequency and phase. this is particularly true in hardware mode with multiple cs8415a devices where synchronization between devices is important. rmck 10 recovered master clock ( output ) - recovered master clock output wh en pll is locked to the incoming aes3 stream. frequency is 256x the sample rate (fs). rerr 11 receiver error ( output ) - when high, indicates an error condition in the aes3 receiver. the status of this pin is updated once per sub-fr ame of incoming aes3 data. condition s that can cause rerr to go high are: validity bit high, parity error, bi-phase coding error, and loss of lock by the pll.
cs8415a 32 rcbl 12 receiver channel status block ( output ) - indicates the beginning of a received channel status block. rcbl goes high two frames after the recepti on of a z preamble, remains high for 16 frames while copy, orig, audio, emph and pro are updated, and returns low for the remainder of the block. rcbl changes on rising edges of rmck. pro 13 pro channel status bit ( output ) - reflects the state of the professional/consumer channel status bit in the incoming aes3 data stream. low indicates consumer and high indi cates professional. chs 14 channel select (input) - selects which sub-frame?s channel status data is output on the emph , copy, orig, pro and audio pins. channel a is selected when chs is low, channel b is selected when chs is high. nverr 15 no validity receiver error indicator ( output ) - a high output indicates a problem with the operation of the aes3 receiver. the status of this pin is update d once per frame of incoming aes3 data. conditions that cause nverr to go high are: parity error, and bi-phase coding error, and loss of lock by the pll. osclk 16 serial audio output bit clock ( input / output ) - serial bit clock for audio data on the sdout pin. olrck 17 serial audio output left/right clock ( input / output ) - word rate clock for the audio data on the sdout pin. frequency will be the output sample rate (fs). sdout 18 serial audio output data ( output ) - audio data serial output pin. this pin is also a start-up option which determines if the serial audio port is master or slave. a 47 k ? resistor to either vl+ or dgnd is required. audio 19 audio channel status bit ( output ) - reflects the state of the audio/non audio channel status bit in the incoming aes3 data stream. when this bit is low a valid audio stream is indicated. dgnd3 dgnd2 dgnd 20 21 22 digital ground ( input ) - ground for the digital circuitry in the chip. dgnd and agnd should be con- nected to a common ground area under the chip. h/s 24 hardware/software mode control ( input ) - determines the method of controlling the operation of the cs8415a, and the method of accessing cs and u data . in software mode, device control and cs and u data access is primarily through the control port, using a microcontroller. hardware mode provides an alternate mode of operation and access to the cs and u data through dedicated pins. this pin should be permanently tied to vl+ or dgnd. u 25 user data ( output ) - outputs user data from the aes3 receiv er, clocked by the rising and falling edges of olrck. c 26 channel status data ( output ) - outputs channel status data from the aes3 receiver, clocked by the ris- ing and falling edges of olrck. orig 28 original channel status ( output ) - scms generation indicator. this is decoded from the incoming cat- egory code and the l bit in the channel status bits. a low output indicates that the source of the audio data stream is a copy not an original. a high indicates that the audio data stream is original. this pin is also a start-up option which, along with emph , determines the serial audio port format. a 47 k ? resistor to either vl+ or dgnd is required.
cs8415a 33 12. applications 12.1 reset, power down and start-up when rst is low, the cs8415a enters a low pow- er mode and all internal states are reset, including the control port and registers, and the outputs are muted. when rst is high, the control port be- comes operational and the desired settings should be loaded into the control registers. writing a 1 to the run bit will then cause the part to leave the low power state and begin operation. after the pll has settled, the serial audio outputs will be enabled. some options within the cs8415a are controlled by a start-up mechanism. during the reset state, some of the output pins are reconfigured internally to be inputs. immediately upon exiting the reset state, the level of these pins is sensed. the pins are then switched to be outputs. this mechanism allows output pins to be used to set alternative modes in the cs8415a by connecting a 47 k ? re- sistor to between the pin and either vl+ (hi) or dgnd (lo). for each mode, every start-up option select pin must have an external pull-up or pull- down resistor. in software mode, the only start-up option pin is emph , which is used to set a chip ad- dress bit for the control port in i 2 c mode. the hard- ware mode uses many start-up options, which are detailed in the hardware definition section at the end of this data sheet. 12.2 id code and revision code the cs8415a has a register that contains a 4-bit code to indicate that the addressed device is a cs8415a. this is useful when other cs84xx fam- ily members are resident in the same system, al- lowing common software modules. the cs8415a 4-bit revision code is also available. this allows the software driver for the cs8415a to identify which revision of the device is in a particu- lar system, and modify its behavior accordingly. to allow for future revisions, it is strongly recommend that the revision code is read into a variable area within the microcontroller, and used wherever ap- propriate as revision details become known. 12.3 power supply, grounding, and pcb layout for most applications, the cs8415a can be oper- ated from a single +5 v supply, following normal supply decoupling practices, see figure 5. note that the i 2 c protocol is supported only in 5v mode. for applications where the recovered input clock, output on the rmck pin, is required to be low jitter, then use a separate, quiet, analog +5 v supply for va+, decoupled to agnd. in addition, a separate region of analog ground plane around the filt, agnd, va+, rxp0-6 and rxn0 pins is recom- mended. extensive use of power and ground planes, ground plane fill in unused areas and surface mount de- coupling capacitors are recommended. decou- pling capacitors should be mounted on the same side of the board as the cs8415a to minimize in- ductance effects, and all decoupling capacitors should be as close to the cs8415a as possible.
cs8415a 34 13. package dimensions inches millimeters dim min nom max min nom max a 0.093 0.098 0.104 2.35 2.50 2.65 a1 0.004 0.008 0.012 0.10 0.20 0.30 b 0.013 0.017 0.020 0.33 0.42 0.51 c 0.009 0.011 0.013 0.23 0.28 0.32 d 0.697 0.705 0.713 17.70 17.90 18.10 e 0.291 0.295 0.299 7.40 7.50 7.60 e 0.040 0.050 0.060 1.02 1.27 1.52 h 0.394 0.407 0.419 10.00 10.34 10.65 l 0.016 0.026 0.050 0.40 0.65 1.27 0 4 8 0 4 8 jedec #: ms-013 controlling dimension is millimeters 28l soic (300 mil body) package drawing d h e b a1 a c l seating plane 1 e
cs8415a 35 notes: 1. ?d? and ?e1? are reference datums and do not included mold flash or protrusions, but do include mold mismatch and are measured at the parting line, mold flash or protrusions shall not exceed 0.20 mm per side. 2. dimension ?b? does not include dambar protrusion /intrusion. allowable dambar protrusion shall be 0.13 mm total in excess of ?b? dimension at maximu m material condition. dambar intrusion shall not reduce dimension ?b? by more than 0.07 mm at least material condition. 3. these dimensions apply to the fl at section of the lead between 0.10 and 0.25 mm from lead tips. inches millimeters note dim min nom max min nom max a -- --0.47-- --1.20 a1 0.002 0.004 0.006 0.05 0.10 0.15 a2 0.03150 0.035 0.04 0.80 0.90 1.00 b 0.00748 0.0096 0.012 0.19 0.245 0.30 2,3 d 0.378 bsc 0.382 bsc 0.386 bsc 9.60 bsc 9.70 bsc 9.80 bsc 1 e 0.248 0.2519 0.256 6.30 6.40 6.50 e1 0.169 0.1732 0.177 4.30 4.40 4.50 1 e -- 0.026 bsc -- -- 0.65 bsc -- l 0.020 0.024 0.029 0.50 0.60 0.75 0 4 8 0 4 8 jedec #: mo-153 controlling dimension is millimeters. 28l tssop (4.4 mm body) package drawing e n 1 23 e b 2 a1 a2 a d seating plane e1 1 l side view end view top view
cs8415a 36 14. appendix a: external aes3/spdif/iec60958 receiver components 14.1 aes3 receiver external components the cs8415a aes3 receiver is designed to accept both the professional and consumer interfaces. the digital audio specifications for professional use call for a balanced receiver, using xlr con- nectors, with 110 ? 20% impedance. the xlr connector on the receiver should have female pins with a male shell. since the receiver has a very high input impedance, a 110 ? resistor should be placed across the receiver terminals to match the line impedance, as shown in figure 10. although transformers are not required by the aes, they are, however, strongly recommended. if some isolation is desired without the use of trans- formers, a 0.01 f capacitor should be placed in series with each input pin (rxp0 and rxn0) as shown in figure 11. however, if a transformer is not used, high frequency energy could be coupled into the receiver, causing degradation in analog performance. figures 10 and 11 show an optional dc blocking capacitor (0.1 f to 0.47 f) in series with the ca- ble input. this improves the robustness of the re- ceiver, preventing the saturation of the transformer, or any dc current flow, if a dc voltage is present on the cable. in the configuration of systems, it is important to avoid ground loops and dc current flowing down the shield of the cable that could result when boxes with different ground potentials are connected. generally, it is good practice to ground the shield to the chassis of the transmitting unit, and connect the shield through a capacitor to chassis ground at the receiver. however, in some cases it is advan- tageous to have the ground of two boxes held to the same potential, and the cable shield might be depended upon to make that electrical connection. generally, it may be a good idea to provide the op- tion of grounding or capacitively coupling the shield to the chassis. in the case of the consumer interface, the stan- dards call for an unbalanced circuit having a re- ceiver impedance of 75 ? 5%. the connector for the consumer interface is an rca phono socket. the receiver circuit for the consumer interface is shown in figure 12. figure 13 shows an imple- mentation of the input s/pdif multiplexer using the consumer interface. the circuit shown in figure 14 may be used when external rs422 receivers, optical receivers or oth- er ttl/cmos logic outputs drive the cs8415a re- ceiver section. 14.2 isolating transformer requirements please refer to the application note an134: aes and spdif recommended transformers for re- sources on transformer selection. 1 xlr twisted pair 110 ? 110 ? cs8415a rxp0 rxn0 * see text 1 xlr twisted pair 110 ? 110 ? cs841 5a rxp0 rxn0 0.01 f 0.01 f *seetext figure 10. professional input circuit figure 11. transformerless professional input circuit
cs8415a 37 rca phono rxp0 rxn0 cs8415a coax 75 ? 75 ? 0.01 f 0.01 f rxp6 rxn0 rxp0 rxp5 75 ? .01 f .01 f .01 f . . . .01 f 75 ? coax 75 ? 75 ? 75 ? coax 75 ? coax figure 12. consumer input circuit figure 13. s/pdif mux input circuit rxp0 rxn0 cs8415a 0.01 f 0.01 f ttl/cmos gate figure 14. ttl/cmos input circuit
cs8415a 38 15. appendix b: channel status and user data buffer management 15.1 aes3 channel status (c) bit management the cs8415a contains sufficient ram to store a full block of c data for both a and b channels (192 x 2 = 384 bits), and also 384 bits of u information. the user may read from these buffer rams through the control port. the buffering scheme involves 2 block-sized buff- ers, named d and e, as shown in figure 15. the msb of each byte represents the first bit in the se- rial c data stream. for example, the msb of byte 0 (which is at control port address 20h) is the con- sumer/professional bit for channel status block a. the first buffer (d) accepts incoming c data from the aes receiver. the 2nd buffer (e) accepts entire blocks of data from the d buffer. the e buffer is also accessible from the control port, allowing reading of the c data. 15.2 accessing the e buffer the user can monitor the incoming data by reading the e buffer, which is mapped into the register space of the cs8415a, through the control port. the user can configure the interrupt enable regis- ter to cause interrupts to occur whenever d to e buffer transfers occur. this allows determination of the allowable time periods to interact with the e buffer. also provided is a d to e inhibit bit. this may be used whenever ?long? control port interactions are occurring. a flowchart for reading the e buffer is shown in figure 16. since a d to e interrupt just occurred af- ter reading, there is a substantial time interval until the next d to e transfer (approximately 24 frames worth of time). this is usually plenty of time to ac- cess the e data without having to inhibit the next transfer. 15.2.1 reserving the fi rst 5 bytes in the e buffer d to e buffer transfers periodically overwrite the data stored in the e buffer. the cs8415a has the capability of reserving the first 5 bytes of the e buff- er for user writes only. when this capability is in use, internal d to e buffer transfers will not affect the first 5 bytes of the e buffer. therefore, the user can set values in these first 5 e bytes once, and the settings will persist until the next user change. this mode is enabled using the channel status data buffer control register. control port from aes3 receiver e 24 words 8-bits 8-bits ab d received data buffer figure 15. channel status data buffer structure dtoeinterruptoccurs optionally set d to e inhibit read e data if set, clear d to e inhibit return figure 16. flowchart for reading the e buffer
cs8415a 39 15.2.2 serial copy management system (scms) in software mode, the cs8415a allows read ac- cess to all the channel status bits. for consumer mode scms compliance, the host microcontroller needs to read and interpret the category code, copy bit and l bit appropriately. in hardware mode, the scms protocol can be fol- lowed by either using the copy and orig output pins, or by using the c bi t serial output pin. these options are documented in the hardware mode section of this data sheet. 15.2.3 channel status data e buffer access the e buffer is organized as 24 x 16-bit words. for each word the ms byte is the a channel data, and the ls byte is the b channel data (see figure 15). there are two methods of accessing this memory, known as one byte mode and two byte mode. the desired mode is selected by setting a control regis- ter bit. 15.2.3.1 one byte mode in many applications, the channel status blocks for the a and b channels will be identical. in this situ- ation, if the user reads a byte from one of the chan- nel's blocks, the corresponding byte for the other channel will be the same. one byte mode takes ad- vantage of the often identical nature of a and b channel status data. when reading data in one byte mode, a single byte is returned, which can be from channel a or b data, depending on a register control bit. one byte mode saves the user substantial control port access time, as it effectively accesses 2 bytes worth of information in 1 byte's worth of access time. if the control port's autoincrement addressing is used in combination with this mode, multi-byte accesses such as full-block reads can be done es- pecially efficiently. 15.2.3.2 two byte mode there are those applications in which the a and b channel status blocks will not be the same, and the user is interested in accessing both blocks. in these situations, two byte mode should be used to access the e buffer. in this mode, a read will cause the cs8415a to out- put two bytes from its control port. the first byte out will represent the a channel status data, and the 2nd byte will represent the b channel status data. 15.3 aes3 user (u) bit management entire blocks of u data are buffered using a cas- cade of 2 block-sized rams to perform the buffer- ing. the user has access to the second of these buffers, denoted the e buffer, through the control port. the u buffer access only operates in two byte mode, since there is no concept of a and b blocks for user data. the arrangement of the data is as fol- lowings: bit15[a7]bit14[b7]bit13[a6]bit12[b6]...bit1[a0]bit 0[b0]. the arrangement of the data in the each byte is that the msb is the first received bit and is the first transmitted bit. the first byte read is the first byte received, and the first byte sent is the first byte transmitted. if you read two bytes from the e buffer, you will get the following arrangement: a[7]b[7]a[6]b[6]....a[0]b[0].
cs8415a 40 16. appendix c: pll filter 16.1 general an on-chip phase locked loop (pll) is used to re- cover the clock from the incoming data stream. figure 17 is a simplified diagram of the pll in these parts. when the pll is locked to an aes3 in- put stream, it is updated at each preamble in the aes3 stream. this occurs at twice the sampling frequency, f s . when the pll is locked to ilrck, it is updated at f s so that the duty cycle of the input doesn?t affect jitter. there are some applications where low jitter in the recovered clock, presented on the rmck pin, is important. for this reason, the pll has been de- signed to have good jitter attenuation characteris- tics, as shown in figure 19. in addition, the pll has been designed to only use the preambles of the aes3 stream to provide lock update informa- tion to the pll. this results in the pll being im- mune to data dependent jitter affects because the aes3 preambles do not vary with the data. the pll has the ability to lock onto a wide range of input sample rates with no external component changes. if the sample rate of the input subse- quently changes, for exam ple in a varispeed appli- cation, the pll will only track up to 12.5% from the nominal center sample rate. the nominal cen- ter sample rate is the sample rate that the pll first locks onto upon applicat ion of an aes3 data stream or after enabling the cs8415a clocks by setting the run control bit. if the 12.5% sample rate limit is exceeded, the pll will return to its wide lock range mode and re-acquire a new nominal center sample rate. phase comparator and charge pump n vco rmck input c rip c filt r filt figure 17. pll block diagram
cs8415a 41 16.2 external filter components 16.2.1 general the pll behavior is affected by the external filter component values. figure 5 shows the recom- mended configuration of the two capacitors and one resistor that comprise the pll filter. in table 4, the component values shown for the 32 to 96khz range have the highest corner frequency jit- ter attenuation curve, takes the shortest time to lock, and offers the best output jitter performance. the component values shown for the 8 to 96khz range allows the lowest input sample rate to be 8 khz, and increases the lock time of the pll. lock times are worst case for an fsi transition of 96 khz. 16.2.2 capacitor selection the type of capacitors used for the pll filter can have a significant effect on receiver performance. large or exotic film capacitors are not necessary as their leads and the required longer circuit board traces add undesirable inductance to the circuit. surface mount ceramic capacitors are a good choice because their own inductance is low, and they can be mounted close to the filt pin to minimize trace inductance. for c rip , a c0g or npo dielectric is recommended, and for c filt , an x7r dielectric is preferred. avoid capacitors with large temperature co-efficients, or capacitors with high dielectric constants, that are sensitive to shock and vibration. these include the z5u and y5v dielectrics. 16.2.3 circuit board layout board layout and capacitor choice affect each other and determine the performance of the pll. figure 18 contains a suggested layout for the pll filter components and for bypassing the analog supply voltage. the 0.1 f bypass capacitor is in a 1206 form factor. r filt and the other three capacitors are in an 0805 form factor. the traces are on the top surface of the board with the ic so that there is no via inductance. the traces themselves are short to minimize the inductance in the filter path. the va+ and agnd traces extend back to their origin and are shown only in truncated form in the drawing. va+ agnd filt c filt 1000 pf .1f r filt c rip figure 18. recommended layout example
cs8415a 42 16.2.4 component value selection the external pll component values are listed in table 4. 16.2.5 jitter attenuation shown in figure 19 is the jitter attenuation plot when used with the 36-96khz pll component val- ues. the aes3 and iec 60958-4 specifications state a maximum of 2db jitter gain or peaking. fs range r filt (k ? )c filt ( f) c rip (nf) pll lock time (ms) 8 - 96 0.909 1.8 33 56 32 - 96 3.0 0.047 2.2 60 table 4. external pll component values figure 19. jitter attenuation characteristics of pll with fs=32 to 96 khz filter components 10 ?1 10 0 10 1 10 2 10 3 10 4 10 5 ?20 ?15 ?10 ?5 0 5 jitter frequency (hz) jitter attenuation (db)

▲Up To Search▲

Price & Availability of CS8415A-IZ

	To Download CS8415A-IZ Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .