08-11-2006, 02:02 AM
I'v seen this forum 4 month ago, and I was very happy because I also want to connect Ipod to my head unit.
I tried the code, and it worked But since Ipod doesen't have SPDIF out I have decidec to make my own converter . After a few weeks of design and tips form CS the converter is ready ( At least the schematics ). It should work without a problem according to the chip's manufachter.
I didn't have the time and the possibility to try it, but I will do it in the next weeks.
It is designed to have a PIC and a max232 in the same circuit to make it complete. The Pic is 16F88 and it has been tested to work. ( Still displays CD 0 TR1 .
If anybody is interested then I will post the schematics and the hex also.
08-11-2006, 03:53 AM
Of course we are all interested
08-11-2006, 04:52 AM
Here is the schematics.
Hope I've helped you.
08-11-2006, 05:12 AM
Sorry I forgot some additional info.
The converter uses a CS5330/CS5330 delta-sigma ad converter, and CS8406 SPDIF transmitter. The circuit generates 18 Bit, 48 khz Stereo signal.
Of course you can easily modificate it to 24 bit 196 khz, but then you have to replace th cs5330 to cs5340 ( I think ). And also you have to add another preamplifier, and modificate the connection of cs8406 ( take care about the data flow, etc. ). Also you have to replace the transformer because it is only valid up to ~60 khz ( for example PE-65612 ).
Both cs ics are from Cirrus Logic. The TLC272 is a pre-amplifier. And a reset ic is required. The current one is from Dallas/Maxim.
Before anybody trie it please read the datasheets carefully because the circuit is very sensitive to grounding shields, and the type of capacitors.
If you can try it before me please let me know.
08-11-2006, 05:24 AM
This looks great, thanks for the info!
I'll have to look at this with a friend that understands electronics better than me, and I'll tell you for sure how this works out. Did you program the PIC yourself or you used the PIC code that was on this forum ?
Why did you go for 18bit/48kHz and not 16bit/44.1kHz ? (just curious)
Do you have to program the SPDIF chips or you just plug them ?
08-11-2006, 05:32 AM
The only chip you have to program is the PIC. The program is vritten by ( the original source is from the froum ) me in mikropascal. It fits in the 2k size demo limit of compiler.
All you have to do is to solder the other ics
The 18 bit comes from the chip ( I don't think it can be modificated ).
The khz can be set with the Master Clock ( 12.288 Mhz = 48 khz ). I only could get this cristal . It can be set 32-49 khz on CS5330, but the cs8406 supporst 256x and 512x fosc settings not 386x. If you read the dataseheet of 5330 you will see that how can you set the Master Clock, and fosc ( also set it on 8406 ).
And the source of PIC
08-11-2006, 07:53 AM
On a related note, anybody knows which bit/sample rates of SPDIF the head unit accepts ?
08-14-2006, 09:59 AM
SPDIF encoding solutions
For those who have a CarPC but no SPDIF output, I found this solution based on similar chips but converting USB to SPDIF, so that's another "no-analog" solution.
Of course, as Foldesa mentioned above, you have to solder these beasts and as they are surface-mount, you'd better have advanced soldering skills - not my case :-)
Just my 2 cents
08-15-2006, 06:43 AM
According to the datasheet of the head unit's main chip the acceptable sample rates are 32, 44.1, 48, 96 khz, but I'm not sure.
Originally Posted by FroMage
I have made a few changes on my desing. The digital and analog parts are separated. And it is easyer to understand now.
The Digital part contains the power suply and the clock generation. The 3 pin connectors are jumpers, so this way every setting of cs8406 can be easily changed.
The 2 other schematics are the analog-digital converters. The analog-1 is CS5330 or CS5331 ( they are pin compatible ). This is 18 bit.
The analog-2 is better, but more complicated. You can use here CS5361 or CS5381, they are also pin compatible. This conncection can go up to 192 khz, but the head unit may not accept a high resolution like this. This connection is 24 bits instead of 18 bits, so it has better sound quality.
08-15-2006, 08:19 AM
Thank you all guys, but all this info is way too much for a normal non-electro technician user, so here is my question:
Could anybody post an easy to read and understand scheme, so anybody who has a basic electro knowledge could sold it together and connect a MP3 player to the CD IN on the head unit?
I know some newer head units have the AUX IN on them, but some of us don't have that luck.
I know you can find the adapter for it online, but with the price of over 100 Euros is way too expensive - you could rather buy a new head unit for the price