[Techtoolslist] Atari 6502A NOP adapter

[John Robertson]

electronicamuse at aol.com wrote:

> Does anybody sell laid out PCBs for making NOPs?

>

> I know that it's not tough to make them from scratch, but would nice 

> to just have them already started.

>

> thanks

>

>

> Dave

>

I simply used good CPUs (6800, Z80, etc.) and bent the Data and Reset 
pins up over the top of the IC. Then I hooked the Data lines to 
correspond to the NOP instruction grounding or Vccing for '0' or '1'. 
Z80 you have to lift the Halt pin as well. Tie any essential pins ( for 
the CPU to run) to Vcc via 3K6 resistors. Reset can often be faked with 
a 10ufd and 10K resistor for the Reset pin.

I was not aware of the 6502 NOP bit but using a 6502 with the Data lines 
tied in NOP worked for me!

John :-#)#

>

> -----Original Message-----

> From: martin at guddler.co.uk <martin at guddler.co.uk>

> To: Technical Tools Mail List <techtoolslist at flippers.com>be

> Sent: Sun, 25 Jan 2009 12:32 pm

> Subject: Re: [Techtoolslist] Atari 6502A NOP adapter

>

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> Thanks for the info Tim. 

>  

>

> I've made a new NOP adapter today that just uses a pair of LS393s as a 

> 16 bit counter as per the CAT box schematics and am now getting Atari 

> signatures! 

>  

>

> Martin. 

>  

>

> On 25 Jan 2009, at 02:22, teeray wrote: 

>  

...

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