Looking for a pesky data sheet - SAA7709H - Page 1
Forum section: electronics / beginners

author: viperidae
author_rank: Frequent Contributor
timestamp: November 30, 2019, 04:19:08 am
content: I've been looking for a datasheet for the software part of a Philips SAA7709H.I've found lots of copies of the hardware datasheet, where it saysQuoteMy goal is to control the input selection and DSP functions of it with an Arduino/Nucleo over I2C, but that's not going to be easy without information about the registers and how it works.The one that starts withQuoteis the one I already found. My Google-foo must of off today

author: jhpadjustable
author_rank: Frequent Contributor
timestamp: November 30, 2019, 06:37:37 am
content: When a chip contains licensed technologies like Dolby whatever whose use needs to be restricted solely to licensees, register programming information is sometimes distributed only under NDA. Sometimes, you can web search to find aLinux driver for a (hopefully) similar enough chipthat (hopefully) contains enough register programming information to get you started, and maybe even thenotes of other hardware hackerswho have tried to do something similar.

author: viperidae
author_rank: Frequent Contributor
timestamp: November 30, 2019, 08:12:46 pm
content: Bugger. Seems like it's going to be easier to remove the DSP and find another chip to do source select, volume and fader control

author: CircuitChaos
author_rank: Contributor
timestamp: April 02, 2023, 07:52:03 pm
content: Hi. I just found this forum by searching for this exact PDF. Were you able to find it?I'm trying to add AUX support to the radio using this IC by communicating with this chip via I2C, but without a documentation it might be… hard.

author: Jwillis
author_rank: Super Contributor
timestamp: April 02, 2023, 08:54:16 pm
content: Obsolete part according to Digikey.https://www.digikey.com/en/products/detail/nxp-usa-inc/SAA7709H-N104-518/2296387?WT.z_cid=ref_findchips_standard&utm_campaign=buynow&utm_medium=aggregator&utm_source=findchipsTry expanding search .https://www.digikey.com/en/products/base-product/nxp-usa-inc/568/SAA77/143097Maybe you might find somethingTry this maybe and expand other suppliers on digikey.https://www.digikey.com/en/products/detail/nxp-usa-inc/SAA7709H-N103S-557/2296637I'm not a programmer so I'm not sure if this would help or not . I t looks like theirs something in ths about addressing ?https://manualzz.com/doc/19484583/nxp-saa7706h-car-radio-digital-signal-processor--dsp--dat...

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: April 03, 2023, 11:40:23 pm
content: They may have something in the concise catalog or the audio one that came with it.I will look tuesday.Jeff

author: CircuitChaos
author_rank: Contributor
timestamp: April 04, 2023, 12:57:03 am
content: Quote from: Jwillis on April 02, 2023, 08:54:16 pmIt's a similar, but different chip. The protocol might be similar though. I'll take a look after I do some snooping on the lines.Quote from: Jeff eelcr on April 03, 2023, 11:40:23 pmThanks, I'll appreciate it.

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: April 05, 2023, 12:57:03 am
content: My 1996 catalog does not contain it and the audio book was IC01had the SAA7707H IC was the closest that was 1997.I had nothing newer than those books from Philips.Jeff

author: CircuitChaos
author_rank: Contributor
timestamp: April 05, 2023, 01:26:52 am
content: Thanks for checking, Jeff. Could you share at least the SAA7707H datasheet (if it contains information about I2C commands, registers, etc.)? Hopefully they're similar enough…I connected the oscilloscope to SCL to see the speed I'll be dealing with. Over 300 kHz. My DIY logic analyzer can't handle that much, so I ordered a Saleae clone that, as the seller claims, samples at 24 MHz sample rate. Looks a bit too optimistic for that price (around $10), but we'll see…

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: April 06, 2023, 02:37:44 am
content: The IC01 book only contains the preliminary description, pinout and block diagram.the IC12 book title says "I2C peripherals" I do not have that one.Jeff

author: CircuitChaos
author_rank: Contributor
timestamp: April 06, 2023, 10:50:47 am
content: I see. Well, thanks for checking. I'm waiting for the logic analyzer to arrive and maybe I'll come out with something.My idea is to hook a microcontroller parallel to the SCL and in series with the SDA, and modify commands sent to the DSP to select AUX when user selects AM radio (first I tried just hooking audio signal to the AM radio input, but DSP heavily filters it… which is good for AM radio reception, but horrible for music with a wider bandwidth).The other thing is if my MCU (I was thinking of just using a cheap ATtiny) will be able to keep up with the 300+ kHz clock speed (I might add clock stretching, but I don't know if the radio's MCU supports it). I'll see. Anyway, the first step is to analyze the communication.

author: Andy Watson
author_rank: Super Contributor
timestamp: April 06, 2023, 11:50:35 am
content: Quote from: Jeff eelcr on April 06, 2023, 02:37:44 amGo here if you want the IC12 book (towards the bottom of the page).http://www.bitsavers.org/components/philips/_dataBooks/Althouhg, it doesn't appear to contain any information spcific to the SAA7709 - any version.

author: CircuitChaos
author_rank: Contributor
timestamp: April 06, 2023, 11:39:56 pm
content: Ok, so the new logic analyzer arrived and I was able to snoop on the bus.From what I gathered:• 7-bit device address is 0x1c• all register addresses are (probably) 2-byte• register sizes differ, most seem to be 3-byte• every 250 ms MCU reads registers 03b0, 0307 and 030f, their values differ• before band is changed, MCU writes something to registers 003b, 003a and 0335 (the same value to 003b and 003a, and zeroes to 0335)• changing the band involves exchanging (mostly writing) enormous amount of data – way too much for a simple input selection• a part of this communication involves repeated writes to registers 10fa, 01fb, 01fc, 01fd• register maps for SAA7706H and SAA7709H are different• hardware documentation mentions that registers 0ff9 and 0ffa are involved in input selection, but I can't find them in communication (I also looked for registers with slightly lower addresses, hoping that autoincrement would take me to these registers, but didn't find anything)Frankly, I give up, at least until I find the I2C documentation (which, sadly, seems to be impossible). I'll explore the CD changer emulation possibility, but I'm posting the captured communication (and I'm keeping the notifications enabled for this thread in case someone stumbles across the pesky data sheet) – maybe someone smarter or more determined than me will find this thread in the future looking for the documentation and will have a starting point to do some magic…There are two switch-to-am files, because I enabled both AM bands.

author: dj-bobr
author_rank: Newbie
timestamp: May 25, 2023, 10:44:58 pm
content: I am also interested. SAA7709H is a main DSP chip also in Honda Accord 7gen stock radio and I am desperately looking for I2C command list.I already managed to enable AUX input in the car radio, successfully traced PCB paths, also sniffed a bit of comms to DSP with Saleae but I am probably not wise enough to crack this.Why I want the docs: I am annoyed of adding bass at 100-150Hz when EQing "bass level" and I want to get more bass without adding mud above 100Hz. Also I want to compensate some frequency dips and hills and I read that SAA7709H is equipped with 5 parametric EQs so I prefer to program SAA instead of embedding ADAU1701 DSP into the device.