Vectorlist Archives: RE: Space Duel PCB weirdness

From: Chris Brooks <armis_at_pcdochouston.com>
Date: Mon Jan 26 2009 - 22:19:50 EST

Hi Matt,

Not at all - the processor pins just stop. It really is baffling me - I'm
looking to get a logic analyzer here sometime this week - I think it's the
only way to really see what the processor is doing. Unless you have a trick
up your sleeve? :)

Thanks,

Chris Brooks

713-931-0975

-----Original Message-----
From: Matt J. McCullar [mailto:mccullar@flash.net]
Sent: Monday, January 26, 2009 8:59 PM
To: vectorlist@vectorlist.org
Subject: RE: VECTOR: Space Duel PCB weirdness

Howdy, Chris! I'm in Arlington, between Fort Worth and Dallas. Where in
Texas are you?

Can you put the board into self-test at all?

Matt J. McCullar

-----Original Message-----
From: owner-vectorlist@vectorlist.org
[mailto:owner-vectorlist@vectorlist.org]On Behalf Of Chris Brooks
Sent: Monday, January 26, 2009 6:30 AM
To: vectorlist@vectorlist.org
Subject: VECTOR: Space Duel PCB weirdness

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.

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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