How do you mod the PS1 for Digital Audio via TOSLINK?

Hello everyone, since the PS1 has a separate DAC, I was wondering how do you mod the PS1 for digital audio? Any diagrams or tutorials I can follow?

I would really like to get digital audio out of my PS1. I use it on my PS2 but I want it on the PS1 as well.

Any help would be highly appreciated!

 

There was a mod that did this - it used a Toshiba SPDIF encoder chip (TC9231N, I think) - this used to be a very common part (used in a lot of early '90s CD players)but it's been out of production for a long time. From what I remember, it was pretty easy to hook up - it would take the same BCLK/LRCLK/DATA signals that the DAC does, and could be strapped to use the same 384Fs MCLK that's already on the DAC.

I do have a vague memory that the LRCLK signal needed inverting, though - otherwise the L and R channels come out over the digital out swapped.

 

Any diagrams of it?

 

Yes, please! A diagram of this would be much appreciated. I would want to try this as well.

 

Hmm, it looks like it's dropped off the web

This is the original source (via archive.org):

http://web.archive.org/web/20050817164313/http://www.uyouyo.com/special/soundcrd/scph7000.htm

But the graphics are missing - annoyingly, the drawing for the Saturn still has them...

http://web.archive.org/web/20050826000956/http://www.uyouyo.com/special/soundcrd/hst3210.htm

Having said that, the text over the schematic says "It's exactly the same as the PlayStation circuit except in one place. The sole difference in pin 7, which should be connected to GND for the PlayStation (384Fs) but needs to be connected to +5V for the Saturn (256Fs). If you want to use the same board for both, use a jumper." (note: my Japanese sucks, but I'm pretty sure that's what it's saying).

 

So solder pin 7 to ground and then the rest of this will work on the PS1? Where can we get the parts?

I've been using my PS2 to play PS1 games over YPbPr Component and TOSLINK. If I can get this working on my PS1, then I would have a reason to use it again! Well, after I complete my PS1 VGA/RGBS mod.

 

There are people selling that Toshiba chip on ebay, but it's not especially cheap (it used to be a $0.50 part) - the rest of it looks standard, the 'ls04 is just a regular TTL chip and the TOSLINK transmitter is also generic.

 

Would the chip in this guide for the Saturn work? What other components would be needed for this mod?

 

It doesn't look like it - the PSX uses a clock that's at 384Fs, and according to the datasheet:

http://www.cirrus.com/en/pubs/proDatasheet/CS8406_F6.pdf

(Table on page 28) there is no way to select this by physical pin strapping. Confusingly, it looks like you *can* do it in software controlled mode (store 01 in the CLK1/CLK2 bits in the clock control register - see pages 20 and 21), but this would mean hooking an MCU up to the chip to configure it, which seems like overkill.

 

This is intresting, would be lovely to find a reliable source for these IC's and maybe buy bulk (10ish)

 

Using a Texas Instrument DIT4096 :
http://nfggames.com/forum2/index.php?topic=3858.0
It might be of some help

Using a Toshiba TC9231N:
http://kum.dyndns.org/works/daiout/

To keep things easy just use this diagram that TriMesh Supplied:

But pin 7 on the TC9231N goes to ground for ps1.

Then use these diagrams on the PS1 (7000)
Data Pins:

Power:

 

Thats also nice, so there are (ofcource) multiple chips probably compatible with some ps1s.
Connect the dots and make sure the ic understands the PS1 standard it speaks (Im new to spdif and toslink)

 

Yes, it looks like the TI chip can cause interference issues. I would try to source the TC9231N. I just picked 5 up on ebay for 30bones.

 

Toslink / S/PDIF is pretty standard - unfortunately the DAC interface isn't. There are lots of variants, related to which edge of the clock is used, if the bits are left or right justified, if the MSB or LSB is sent first, if the first bit cell is before or after the LRCLK transition, etc, etc.

The best thing is to get the datasheet for the DAC and try to match the parameters with that.

 

This thread is getting good

 

are you into gambling?
http://www.aliexpress.com/item/Free-Shipping-TC9231N/32253786193.html

 

ill try the €3,33 version Ok? ill report back when it arrives

EDIT: Payment Successful: € 3,33 Order Processing Time: 7 Days

 

I love the date code - week 36, 1991 - 24 year old chips...

Edit: And I just checked the format of the signals on the machine I have here (SCPH-7003, PU-18).

LRCLK is 44.1kHz (standard CD sample rate)
MCLK is 16.9344MHz (384Fs)
BCLK is 2.1168MHz (48Fs)

DATA transitions on the falling edge of BCLK (I.E. it's latched on the rising edge)
LRCLK is (unsurpringly) Sony style (I.E. it transitions on the first bit cell of the word).
DATA format is 2-complement, MSB first - the 16 bit word is padded to 24 bits with 0s at the MSB end.

I checked this on the board, then verified it with the DAC datasheet, and it all fits.

 

I've seen some people online saying this mod is not compatible with any PS1 after the SCPH-5xxx series. Is that true and if not, are the install instructions the same for the SCPH-7501?

 

It will work up to the SCPH-700x, but not on the SCPH-750x, SCPH-900x and PSone - they have the DAC integrated into the CD/DSP chip.