Micro SwinSID uses only standard C64 audio output.
You can use both ATMega88 or ATMega88PA but I recommend PA version since it may have better overclocking potential. If you are out of luck PA version my also fail with 32MHz. In this case i can release firmware for 24MHz clock. It is obvious that 32MHz version gives better quality or more features, depending on the firmware design.
This PCB is compatible with current ATmega88 firmware available on this forum that was already tested by Crisp. So there is no need to worry. Generally It will work and only output resistors may eventually require small tweaks to adjust output level or PWM filtering. Not a big deal.
SID registers reading is not implemented yet but version 1.1 of circuit supports this function and i'm going to modify firmware when i get working hardware.
The new Micro SwinSID is rather a transition to the new hardware using a very similar to the old 8515 firmware. With the newer and faster CPU some extra features will be available:
- higher samplerate for better sound quality (with 32MHz clock)
- better filter quality
- no need for TDA DAC thanks to 16bit PWM output
In the future I would like to add:
- support for registers reading
- reflashing directly from C64
- better support for Fanta in space and other tricks
- ADSR bug emulation
- new synth enhancements