Hardnes, a project that uses a real 2a03 in an iPod style nsf player, has had its sources released. A intersting project for the brave or the bold. Kevtris writes:
Well, I was going thru my files and thought I’d release this for anyone who was curious how it worked.
It’s fairly outdated and I’m sorry in advance for the poor quality of the comments (lack thereof) and I bet my 6502 skills sucked too.
Anyways as can be seen from its page, it’s just an Intel flexlogic part, RP2A03G CPU, a 74244 input buffer for the buttons, a 128K SRAM (could be upgraded to 512K easily), and some audio amplification and a 3.3V reg with 7406 for logic level translation to the PS1 memory card.
The memory map and PDS file should be enough to go on for anyone wishing to build something similar.
At the time, uploading data to the card was an incredibly hilariously terrible job. I used a hack to load 3K or so of the 128K file at a time using the EPROM emulator I had. So loading a 128K card image took awhile to do.
Anyways, enjoy.
I got a hardON!