[Techtoolslist] Atari 6502A NOP adapter

[Adam Courchesne]

Not a dumb question at all. A NOP adapter is simply an adapter that you slap
onto a microprocessor to force it to execute nothing but NOP (no-op)
instructions.  The reason you would want to do this is to force the entire
system into a known state, or steady predictable behavior.  Then, you can
use a signature analyzer to probe points on the PCB to debug and find the
source of a problem.
Typically what someone will do is use a NOP adapter in a know, correctly
working system, and probe a bunch of points on the PCB and record a set of
signatures.  Then, if the system ever fails, they can repeat the process and
look for any signatures that differ from the ones recorded.  If the
signature on the input to an IC matches but the signature on the output
didn't, chances are that IC is the problem.



On Thu, Feb 5, 2009 at 3:16 PM, kevin spears <micrologix1500 at yahoo.com>wrote:


> This is surely a dumb question, but what is the purpose of the NOP adapter?

>

>

>

>

>

> _______________________________________________

> Techtoolslist mailing list

> Techtoolslist at flippers.com

> http://seven.pairlist.net/mailman/listinfo/techtoolslist

> FTP site is: ftp://ftp.flippers.com/TTL/TestEquipment

> Archive site: http://seven.pairlist.net/pipermail/techtoolslist/

>




-- 
-Adam
"Please don't judge my God by my inability to follow him"  - Chris Mollins
===============
www.onecircuit.com
www.youtube.com/user/ajcrm125
===============