*Update2* SPDIF Audio mod Sega Saturn with *ahem* big pics

[brendanraymond]

For my Sega saturn...

I was wanting to do this mod. http://gamesx.com/wiki/doku.php?id=av:saturn_sp_dif

My Audio chip is a Philips Noise Shaping filter (no SPDIF) TDA1386T.

I can buy a CS8406 chip but I am slightly confused on how I am to wire this.

I want to be able to switch between analoge audio and digital audio... so I will need to switch between.

ISCLK (pin13) Serial Audio Bit Clock (Input/Output) - Serial bit clock for audio data on the SDIN pin. to BCK (pin4) bit clock input.

ILRCK (pin12) Serial Audio Input Left/Right Clock (Input/Output) - Word rate clock for the audio data on the SDIN to WS (pin5) word select input pin.

... but I have no idea if those two channels plus the serial audio line is the same format. I hope so...

As for the rest of the pins, id switch between pin9/15 , pin3/13 , pin21/12 and hook up grounds and +5V where shown on the wiki.

But the largest worry I have is what am I supposed to do with pin3/13 (AD2/EMPH/APP3)?

The TDA1386T de-emphasis line being low indicates no de-emphasis. The EMPH line on the CS8406 low indicates signal pre-emphasis. This meens the emph line has to be inverted. (Or you could just assume no pre-emphasis and tie the EMPH line high)

I cant work out what the minimum and maximum values are for this line. I'm sure there is some sort of modulating chip that can flip the signal... or is that just crazy talk?

I'm abit out of my depth. I'm just a humble mechanical engineer... im not so great with electrical but I try I suppose.

If I can get it to work, I will post up a write up with lots of hi res pics written in plain english so joe blogs can do this mod

Any help would be greatly appreciated

Kind Regards

Brendan

Update: See last post (pg 2)

[winds]

While I can be of no help in this area (sorry haha). I would just like to say if you do get it figured out, that the guide you write up would be very welcomed . I'd love to do this mod but am in the population that needs easy, error-free, idiot guides .

[brendanraymond]

Simplifying the question...

What is the maximum high/low values for de-emphasis/pre-emphasis on each chip? I dont know where to find it in the data sheets

I am thinking about using an XOR gate to invert the signal... but the stregth of the signal might have to be increased/degreased. I hope not

[Mod_Man_Extreme]

Topic moved to the proper hacks and mods section for both forum cleanliness and so you can get some more help!

Personally I've been looking at all these digital audio mods quite intensively ever since I finally got a receiver with digital inputs not too long ago so I hope you get it figured out!

[brendanraymond]

VDDD digital supply voltage (pin 10) note 1
MIN.4.5 TYP.5.0 MAX.5.5

VIH HIGH level digital input voltage (pins 3 to 8 and 11 to 17)
MIN.0.7VDDD TYP.- VDDD + MAX.0.5

VIL LOW level digital input voltage (pins 3 to 8 and 11 to 17)
MIN.-0.5 TYP.- MAX.0.3VDDD V

Done!

So, no all I need is a NOT logic gate that will work with 5v digital signals.

I have a feeling Jaycar isn't going to be able to help me find a chip that can do it.

if anyone knows of a chip or can find out... please let me know

Regards

Brendan

[eSPy]

VDDD digital supply voltage (pin 10) note 1

I have a feeling Jaycar isn't going to be able to help me find a chip that can do it.

Jaycar eh? are you an Aussie or a Kiwi?

[eSPy]

VDDD digital supply voltage (pin 10) note 1

I have a feeling Jaycar isn't going to be able to help me find a chip that can do it.

Jaycar eh? are you an Aussie or a Kiwi?...and yea...i think dick smith might be more likely to have something...but even that would be pushing it

[lisalover1]

What? You can mod a Saturn for optical audio?! I never knew this; I've been planning a big audio setup in my game room for some time now, and I was kind of sad that some of my game systems would sound really weird with stereo audio coming out of more than two speakers. I'm very interested in this mod now. Let us know how it goes, and post pictures when you're done!

[Marspants]

http://gamesx.com/wiki/doku.php?id=av:dreamcastda

If you look here you can see that he changes his method and talks briefly about working on the Saturn if that may be of some use. I would recommend talking to people over at forum for more tech savvy members, but if you do get it working please post the results here! haha

[Mod_Man_Extreme]

What? You can mod a Saturn for optical audio?! I never knew this; I've been planning a big audio setup in my game room for some time now, and I was kind of sad that some of my game systems would sound really weird with stereo audio coming out of more than two speakers. I'm very interested in this mod now. Let us know how it goes, and post pictures when you're done!

Well the mod allows for either optical or coax mods, but that won't give you any more channels than just the two stereo ones as a game needs to be coded in either Dolby Surround (Check most games and usually a good amount have this or just some "Surround" mode in the options or audio options menu.) which is now called Dolby Pro-Logic. Or Dolby Digital which is sadly impossible as the Saturn does not support it due to Dolby Digital not existing for the home market at the time of it's release.

There's also a DA mod for the PS1, N64, Dreamcast, Gamecube, Snes and more, but unfortunately none for the genesis as it handles everything inside the Z80 & YM2612 and produces only an analog signal.