CPC Pico ROM Emulator

Finally the edge connectors arrived and I was able to build the circuit on one of the PCBs supplied by PCBWay.

I added the optional USB interface as well and it all worked first time! The USB interface is compatible with the Albireo card so Alberio DOS or UniDOS work.

I have had one problem with the reset of the CPC from the Pico. This problem was reported to be by a user on the CPC Wiki, but my original prototype worked fine. The PCB version is using a different Pico, so I think I maybe got lucky with the prototype.

I will investigate this further. I'm thinking I will try increasing the drive current on the reset GPIO.

I was not going to design a PCB for this, but then the nice people at PCBWay reached out and offered to make some for free.   So after failing to get Eagle running, a installed KiCad and knocked up a quick PCB. I decided to add a USB adapter based on the CH367 breakout board (similar to Albireo)

I now have the boards back from PCBWay and they look great. I'm waiting on some new edge connectors before I can build them up and test them. Once I have confirmed it works, I will update github

Having recently picked up an old CPC464, I wanted to load some software. First step is to add some sideways ROM. I decided to make my own board as I wanted to learn more about using the Pi Pico and also the CPC.

I'd seen a couple of projects using a micro controller as a ROM emulator, so  I knew it could be done. I'd also seen some projects using the Pico on 5V, apparently with no issues.  I was also fascinated by the PIO inside the Pico. So I did a bit of research and worked out that I would just have enough pins on the Pico to do what I wanted.

Next steps, build the circuit on a proto board, and start coding...