exxos's Atari, Amiga & retro forum

danboid wrote: 13 Jul 2026 08:12 Congrats on getting the A2 running Anders!

Over the weekend, via the EmuTOS mailing list I learned of another very cool open source M68K machine, Y Ddraig (Welsh for The Dragon).

Thank you!
The portability of EmuTOS is really good indeed, and I think a great OS choice for any m68k based machine :)

Have been hunting an ADC issue off and on and finally.. solved! :)
The sampled data was so catastrophically bad that my head was completely locked into thinking it _had_ to be my DSP code and me misunderstanding how to configure ESSI correctly for the i2s data stream.

But in the end, turns out I was missing series capacitor on the audio input to the ADC.
So.. traces cut, capacitors soldered in, and I finally have clean audio coming into the DSP from the ADC :)

Schematics, gerbers and so on which lives on Github has been updated with this fix.

And the external 128 kword SRAM for the DSP has now also been tested and verified working.
With DSP clocked at 90mhz it can do 1 waitstate access to 12ns SRAM so the bootup dsp code configures it for that timing.

agranlund wrote: 14 Jul 2026 21:44 And the external 128 kword SRAM for the DSP has now also been tested and verified working.
With DSP clocked at 90mhz it can do 1 waitstate access to 12ns SRAM so the bootup dsp code configures it for that timing.

Nice! You'll be making @dml mouth water :P

Scrappy bird has fancy toys too now :)


YM2149 -> ADC -> DSP56303 -> DAC -> Lineout
Running an example DSP56001 reverb effect ported to DSP56303.

Awesome! You made chip music slightly less annoying! :lol: :thumbup:

\o/

I guess (obviously) that means you got it all working :)


:dualthumbup:

:cheer: :cheer: :cheer: I'm gonna have to build a second one now :lol:

Well done @agranlund sounds awesome.

Smiles and thumbs up from me too.

The reverb effect is ported from the Falcon DSP. Is it a case of playing back SND Player through an existing DSP realtime effects player, or is there more to it?

I'm thinking of either CT60 or stock Falcon to try this on.

agranlund wrote: 19 Jul 2026 12:38 YM2149 -> ADC -> DSP56303 -> DAC -> Lineout
Running an example DSP56001 reverb effect ported to DSP56303.

great,
what was changed in DSP56001 asm in to run on DSP56303?

dml wrote: 19 Jul 2026 15:01 I guess (obviously) that means you got it all working :)

I don't know about it all yet, have been mesmerised by that shiny new dsp toy so haven't done a full-on testing of absolutely everything yet :)
But the dsp itself appears working, and there is a small subset of dsp xbios routines implemented so far.

asm56k has gotten some 56300 code generation bugs fixed as well so that's been an interesting sidetrack, not being able to fully trust the assembler actually generating valid code when using 56300 specific instructions :)
(to its defense, it does state the 56300 support was largely untested)