Hi there!
I am hoping that someone here with more experience will be able to help me with my first SBC...it isn't working, and I am at my wits end trying to figure out what is going on with it.
First, here's the schematic:
Eagle schematic:
http://ccureau.googlepages.com/mainboard.sch
PDF version:
http://ccureau.googlepages.com/mainboard.pdf
Postscript version:
http://ccureau.googlepages.com/mainboard.ps
Parts list:
CPU: WDC 65c02
ACIA: WDC 65c51
RAM: 2 pieces Toshiba TC55328P-35
ROM: Catalyst CAT28Cc64BG-90
Maxim MAX233
All TTL is HC or HCT technology
I've built it according to the specification on a breadboard, but so far I've not been able to get the thing to work. My ROM is burned with a short program from elsewhere on 6502.org which prompts for an xmodem transfer, then loads that image into memory and executes it. When I apply power, I get absolutely nothing out of the board. :-\
I don't have an oscilloscope, but I am able to test voltages with a DMM. I've single stepped the processor through NOP instructions, and it seems to work fine. I am really not sure what could be wrong, and I would appreciate any helpful hints that anyone has to try to figure this out.
Thanks,
Chris Cureau