Updated: Oct 23, 2021
I have posted previously about my journey to learn a bit about 6502 audio. (A Start to 6502 Audio, 6502 Sound Card -- Suggested changes to this design?, Dynamic Sound Editor, and Playing with Sounds) I recently completed the PCB for my 6502 Sound card. Below is a video summary.
Disclaimer: Use the above schematics and code at your own peril. Much of it is hacked together and could use some serious cleanup. But, you might find it helpful to see how I stitched together the overall solution.
For more information on the SPI configuration used in the video, see Arduino Due, 6502, & SPI... oh my....
As always, questions, feedback, and suggestions are welcome!