Re: Atari 6502A NOP adapter

From: <electronicamuse_at_aol.com>
Date: Sun Jan 25 2009 - 16:15:22 EST

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

-----Original Message-----
From: martin@guddler.co.uk <martin@guddler.co.uk>
To: Technical Tools Mail List <techtoolslist@flippers.com>be
Sent: Sun, 25 Jan 2009 12:32 pm
Subject: Re: [Techtoolslist] Atari 6502A NOP adapter

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: 
 

> OK Guys, 


> A 6502 NOP will not produce sig's that match Atari doc's. 

> Reason is the 6502 takes two clock cycles to do a NOP instruction. 

> The Cat Box takes one clock cycle. 

> So you get double readings of each address. All you need to do is
make 

> an NOP using a couple of counter IC's to cycle through the address >
range 

> on each clock cycle. Or divide the clock by 2 and use this as your >
clock 

> connection for the Analyzer. You can do this with one D type flip >
flop IC. 


> Tim 



> -----Original Message----- 
=0
D
>> From: "martin@guddler.co.uk" <martin@guddler.co.uk> 

>> Sent: Jan 24, 2009 7:38 PM 

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

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

>> 

>> Sorry guys, I should have said, I've got the doc. I've probably got 

>> the one you're pointing too as well John. But I'll pick it up from
TT 

>> tomorrow if not, thank you. 

>> 

>> Nice to see the same people still reading as were here in 2002 as 

>> well :) 

>> 

>> OK. Tomorrow ill put more thought into comparing the two CPUs. The 

>> only thing that really springs to mind at the moment is maybe
they've 

>> messed with the order of the address lines or something? 

>> 

>> The really odd thing is I know for a fact I've fixed centipede
boards 

>> in the past with my 5006. 

>> 

>> Incidentally, I'm now using the 9100 for the sigs. I keep meaning to 

>> post the programs up on my website but they need some refining.
Error 

>> trapping and the like. I've had it producing HP signatures for some 

>> time now. 

>> 

>> I'll post back if I work anything out. Thanks for the pointers >>
though. 

>> 

>> Martin. 

>> 

>> 

>> On Jan 24, 2009, at 20:39, John
Robertson <jrr@flippers.com> wrote: 

>> 

>>> martin@guddler.co.uk wrote: 

>>>> Hi all, 

>>>> 

>>>> Just been trying to find information on what is different about
the 

>>>> KK 6502 (Atari) NOP adapter that makes it produce 8080 signatures 

>>>> as opposed to the normal 6502 ones and I discovered that the 

>>>> question has been posed before - not surprising I guess. 

>>>> 

>>>> Just wandering if this mystery was ever solved and perhaps I'm not 

>>>> looking in the right places? 

>>>> 

>>>> I'm sure I once took down signatures from a working board using my 

>>>> standard 6502 adapter but as always, when I want them, I'm damned 

>>>> if I can find them so maybe I imagined it. 

>>>> 

>>>> In case anyone hasn't a clue what I'm talking about, see the 

>>>> footnote on page 14 of the PDF document "SigAnalNotes.pdf" that 

>>>> ought to be all over the net but I can't find a link to it just
>>>> yet! 

>>>> 

>>>> The original TechTools list message where this was asked before is 

>>>> here (with no answer): 

>>>> http://www.vectorlist.org/TechTools/2002/10/0035.html%c2%a0

>>>> 

>>>> Thanks, 

>>>> Martin. 

>>>> 

>>> Check the FTP archive on TTL (link below) for "Sig-Analy- 

>>> HPJMay77.pdf" this covers some Sig
Analysis questions. I only have 

>>> info on the 6502, 6800 and Z80 NOP fixtures, which is at the rear
of 

>>> "KK-Signature2.pdf" in the KurzKasch section of TTL. 

>>> 

>>> For your question I would print off the last two pages of the 

>>> KK_Signature2.pdf, then pull up info on the 8080, find out what 

>>> instruction gives NOP, and then compare the pinout with the 6502. 

>>> 

>>> John :-#)# 

>>> 

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Received on Sun Jan 25 16:15:41 2009

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