IO Board v5.5: No audio over TOS-link mini

[Kasreyn]

Hi all!

I'm having trouble with audio on the short IO Board v5.5 (I got it back in 2019).

The 3.5 mm has faint and distorted analog audio, the plug has to be half way in to hear anything at all. The main output I wanted to use, namely optical doesn't appear to work at all.

I had a look at the v5.5 schematic and my board does indeed have the "R32" resistor before the LED. R32 seem to be specific to v5.5 where later boards use a different name. I measured R32 with multimeter and it's 200 Ohm.

v5.5 schematics: https://github.com/MiSTer-devel/Hardwar ... rd_5.5.pdf

There's continuity to Pin 9 on the GPIO header and the LED lights up solid (I see no flickering at all from cores) so I don't think it's a broken trace on the board.

I measured the LED voltage with multimeter and it's 1V. In an oscilloscope this is 2V peak and I don't see any data where there should be e.g. with a game loaded in NeoGeo or Arcade (1942, 1943 Kai). The signal is a perfect square wave, 2V always follow 0V. The scope identifies a 48 kHz signal but I don't see any data!

Any idea what's wrong or things that can be tried to enable optical audio?

I have a scope available so I can take a look, maybe even grab screenshots (if I can get it to work).

I've seen suggestions at setting the SW3 switch to ON, I tried this resulting in no output over VGA so I went back to how it is now:
http://opa.crabdance.com/img/MiSTer-IO-board-v5.5.jpg

The INI file I use:
http://opa.crabdance.com/img/MiSTer-IO-board-v5.5.ini

[FritoZipper]

What dose it do when you set all 4 switches to off?, looks like you have SW0 on.

[Kasreyn]

What dose it do when you set all 4 switches to off?, looks like you have SW0 on.

I get the same with all switches off and the same with dvi_mode=1 (HDMI audio off).

[Kasreyn]

A similar topic mention different versions of the NES core, one with audio on v5.5 I/O board !

I never thought to test the NES core, all the ones I tested didn't have audio over TOS-link (Neo Geo, Sega CD, GBA, some arcade cores).

TOS-link audio is coming through loud and clear on NES_20210114.rbf !

.. and now after the NES core it also works in Neo Geo core, glorious TOS-link audio

I'm really not sure what fixed the issue, was it that I loaded the NES core? I did flip all switches to OFF.
Now it works after a cold reboot straight into Neo Geo core.

[FritoZipper]

Glad its working for you now. Tos-link is the way to go, as the DAC in the mister is horrible, even the hdmi audio had some interference noise(at least with my equipment), are you using 96k or 48k? some cores don't output 96k.

[S0urceror]

I recently made a fix for Toslink that is being propagated to all cores. Glad it worked for you!

[Kasreyn]

I recently made a fix for Toslink that is being propagated to all cores. Glad it worked for you!

Thank you so much for that
I really prefer TOSLINK too since I can then more freely select VGA or HDMI source and have audio on both. Note that some capture cards (looking at you SC-512N1-L / PEXCAPHD) do not let you capture VGA video while capturing HDMI audio at the same time.

I think Neo Geo and NES core already have the update in their current releases, while GBA and Genesis need new releases.
At least that's what it looked like when I spied a little in the commit history of GBA.

TOSLINK was not working in GBA_20201120.rbf so I downloaded Quartus (Prime Lite 17.0 + the 17.0.2 update) and compiled the latest sources,
and now it works in GBA I didn't think it would be this easy

If you need it here's a link: http://opa.crabdance.com/bin/GBA_20210210.rbf

[Kasreyn]

TOSLINK also working in latest Genesis core
https://github.com/MiSTer-devel/Genesis ... 210210.rbf

[LamerDeluxe]

I didn't know TOS link didn't work on all cores yet. I didn't get around to testing it yet.

EDIT: Just tested this, wow, it sounds really good. I forgot my Sony amplifier can do stereo speaker simulation (cinema or home) on headphones, even pro logic II surround decoding.

[Kasreyn]

Glad its working for you now. Tos-link is the way to go, as the DAC in the mister is horrible, even the hdmi audio had some interference noise(at least with my equipment), are you using 96k or 48k? some cores don't output 96k.

hdmi_audio_96k=0,

I assume it applies separately and just for HDMI. The MiSTer configuration wiki doesn't mention TOSLINK, or if there are other audio options.

My external card (USB Aureon 7.1) set to 48 KHz has worked with every core so far.

The other standard would be at 44.1 kHz, and it would be good to support that, for compatibility's sake on audio equipment that's out there, right?

[FritoZipper]

Glad its working for you now. Tos-link is the way to go, as the DAC in the mister is horrible, even the hdmi audio had some interference noise(at least with my equipment), are you using 96k or 48k? some cores don't output 96k.

hdmi_audio_96k=0,

I assume it applies separately and just for HDMI. The MiSTer configuration wiki doesn't mention TOSLINK, or if there are other audio options.

My external card (USB Aureon 7.1) set to 48 KHz has worked with every core so far.

The other standard would be at 44.1 kHz, and it would be good to support that, for compatibility's sake on audio equipment that's out there, right?

I think it applys 96k to both hdmi and tos-link, on my Edirol usb capture card noticed a difference on some cores when I changed sample rate in mister settings.

[uzumaki]

SOLVED, nevermind. I had to wiggle and reseat the 3.5mm plug a number of times.

Hey guys, I am having trouble with my toslink as well. My IO board was purchased in Jan 2020 at mister addons. I'm unsure of the revision number and it's inside a case. I am trying to plug in from the mini toslink port to DAC to CRT TV speakers. Those are amplified speakers right, I don't need a separate amp?

I have tried:

• hdmi_audio_96k=0
  volumectl enabled and turned up all the way.
  I can see the red SPDIF light coming from the 3.5mm port and from the end of the mini toslink to spdif cable
  tried 2 DACs
  tried 2 RCA cables
  tried the latest genesis core 2/21 mentioned in this thread
  tried NES, SNES as well
  Audio works out of the 3.5mm analog into headphones

Here is my mister.ini: https://pastebin.com/skChjmhG