A2 proto board update

After an email exchange with Vince Briel where Vince casually indicated that the A2 community really needs a prototyping board, I’ve decided to raise priority and get a batch of these prototype cards built.

I’m a little concerned about timing, especially with the 6522. The Mockingbird board, which also uses the 6522, does some strange stuff with clock timing and I need to really investigate what is going on with a real board. So, before doing the production build, I need to get a prototype proto board working.

Normally, I would just etch a prototype PCB at home, but a proto card needs a bunch of holes drilled in it which would take a long time to do manually and besides, I might need to make some significant changes, which is easy to do with wirewrap. In addition I had on hand an Apple Hobbyboard, which is ideal for this project. The Hobbyboard had been used before for a simple temperature sensor project that I did in the 80’s, but the old circuit had been removed from the board a few years ago. So in the last week, I have wirewrapped the new circuit onto the old Hobbyboard.

prototype proto board

prototype proto board

I haven’t gone very far in debugging because I keep frying the 16V8 GAL chips I’m using to cut down on chip count (and leave more prototyping space). Could be something to do with the ancient Data I/O Pal programmer I”m using. Anyway, there is real progress being made on this project and I hope to get things squared away so I can make a build this spring or summer.