Re: Space Duel PCB weirdness

Chris Brooks wrote:
> Hello all - new to the list, but not arcade stuff :) Howdy from Texas!
>
> Anyway, I have a Space Duel board that is behaving badly and I am stumped
> as to what is going on.
>
> The watchdog barks, so I disabled it, then looked at the CPU bus. It
> appears to address memory for a few milliseconds, then completely stop - no
> activity, address bus locked, data bus locked. Clock looks clean on the
> scope and is operating at the correct frequency.
>
> I would completely understand this happening if it was a processor that
> supported halting or DMA, but the 6502 has no support for such things.
>

Could be missing interrupts. And just because the normal opcodes don't
cause a halt doesn't mean illegal opcodes can't do it.

Also, the ready line (if used) will stop it dead in it's tracks.

> Anyone have a clue on what to look at next? I'm thinking its time to invest
> in a logic analyzer.
>
> Thanks,
>
>
> Chris Brooks
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Received on Mon Jan 26 12:08:05 2009