[Techtoolslist] Developing using the 9100

[Martin White]

Happy New Year to everyone!

I've been doing some hacking about over the holidays with code on a 6502 based PCB (Asteroids as it happens). I've got to the point where I want to debug it on the real hardware so obviously the first thing I wanted to do was try and avoid keep burning ROMs all the time. The code is only really a proof of concept so it's very small. I've relocated my code down to zero page and I can transfer it to the PCB's memory that sits from 0 - 3FF.

On the 9100 that works ok. It's a bit of messing about but I can basically assemble the code, convert it to Intel Hex format, transfer it over serial link and then write it to the PCB's memory and execute it. The only caveat is that I needed to burn a dummy ROM that sits at 7800-7FFF which solely contains the interrupt and reset vectors. So far so good.

The problem is that by the time I've avoided the stack that lives at page 1 (100-1FF) I'm really rather restricted on space. Also by relocating down there I loose the ability to test the code in mame as well. That's not essential but it would be nice to retain that.

So does anyone know if there's any other way? Is there a way where I can keep the code where it's meant to live for instance? Preferably without hacking the PCB to put a RAM in there. The manuals for the 9100 very fleetingly mention something called POD overlay RAM which sounds very promising but I've not been able to find anything much more than just a quick mention.

Any suggestions would be greatly appreciated.

Martin.