> Using a test instrument (pulse stretcher/logic probe, oscilloscope,
> etc.) to monitor the reset line is another thing to check. IIRC,
> they use a 555 timer to generate the reset pulse (common in the
> mid-70s) and I've seen those circuits fail for a variety of reasons.
> You can also build a NOP generator (use a second CPU chip) by bending
> the appropriate data bus leads up and hardwiring the databus to the
> NOP instruction (0xEA?) - You can then use a logic analyzer to monitor
> the address bus for stuck bits and the select lines on the MSI chips
> to see that they respond at the appropriate times.
Hey, that's pretty slick! Yes, $ea is NOP on the 6502.
--
----------------------------- personal page: http://www.armory.com/~spectre/ --
Cameron Kaiser, Point Loma Nazarene University * ckaiser_at_stockholm.ptloma.edu
-- 10% of computer users [use] Mac ... the top 10 percent. -- Douglas Adams ---
Received on Tue Jan 07 2003 - 11:18:00 GMT