[Techtoolslist] 6502 NOP, or Clock divider

[John Robertson]

Kevin Moore wrote:

> I'm looking for some schematics to build a 6502 NOP that will produce catbox

> sigs when used with the HP5004a. I think someone mentioned they built one

> with 2 ls393's I assume that would be the easiest way, instead of building a

> clock divider to use for my clock signal.

>

> If someone could point me in the right direction..

>

> Thanks,

>

> Kevin

> __________


A NOP can easily be built by using a 6502 CPU and bending the data lines 
up over the top, then hardwire them to NOP and disable any watchdog 
reset, then plug the modified CPU into the board and power it up!

I have a picture up on TTL FTP of several modified CPUs and an Eprom 
(can't remember using that - might work), also a PDF of an article 
written back in the 70s about making your own...both of these are files 
starting with "NOP".

John :-#)#