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cknave / c64-pico-ram-interface

Let your Raspberry Pi Pico pretend to be a Commodore 64 ROM cartridge
BSD 3-Clause "New" or "Revised" License
213 stars 15 forks source link

Possible with alternate bus devices? #2

Open mwedmark opened 2 years ago

mwedmark commented 2 years ago

Would it be possible for alternate usage of this hardware? For example:

I guess it is a question of: Free I/O's, Free Pico memory and performance..

cknave commented 2 years ago

This particular design is only capable of emulating a ROM, so you're limited to reading from its memory and using the USB serial port on the Pico as I/O. My interest was in being able to use the Pico's ARM cores as a co-processor and have an "infinite" amount of data (or as much as fits on the flash).

If you're not interested in emulating ROM, there's potential for interfacing with other devices. Depending on how many address lines you need, this will free up a good amount of GPIO pins. There's another PIO unit that you could also use.

The biggest limitations to me are needing to level shift everything between 3.3V and 5V, the limited space for PIO programs, and the limited number of GPIO pins on the Pico. Still not bad for $4!