Re: [Techtoolslist] Atari 6502A NOP adapter

25 Jan 2009

      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: 

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OK Guys, 
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A 6502 NOP will not produce sig's that match Atari doc's. 
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Reason is the 6502 takes two clock cycles to do a NOP instruction. 
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The Cat Box takes one clock cycle. 
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So you get double readings of each address. All you need to do is 
make 
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an NOP using a couple of counter IC's to cycle through the address > 
range 
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on each clock cycle. Or divide the clock by 2 and use this as your > 
clock 
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connection for the Analyzer.  You can do this with one D type flip > 
flop IC. 
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Tim 
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-----Original Message----- 
=0
D
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From: "martin@guddler.co.uk" <martin@guddler.co.uk> 
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Sent: Jan 24, 2009 7:38 PM 
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To: Technical Tools Mail List <techtoolslist@flippers.com> 
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Subject: Re: [Techtoolslist] Atari 6502A NOP adapter 
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Sorry guys, I should have said, I've got the doc. I've probably got 
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the one you're pointing too as well John. But I'll pick it up from 
TT 
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tomorrow if not, thank you. 
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Nice to see the same people still reading as were here in 2002 as 
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well :) 
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OK. Tomorrow ill put more thought into comparing the two CPUs. The 
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only thing that really springs to mind at the moment is maybe 
they've 
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messed with the order of the address lines or something? 
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The really odd thing is I know for a fact I've fixed centipede 
boards 
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in the past with my 5006. 
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Incidentally, I'm now using the 9100 for the sigs. I keep meaning to 
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post the programs up on my website but they need some refining. 
Error 
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trapping and the like. I've had it producing HP signatures for some 
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time now. 
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I'll post back if I work anything out. Thanks for the pointers >> 
though. 
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Martin. 
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On Jan 24, 2009, at 20:39, John 
Robertson <jrr@flippers.com> wrote: 
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martin@guddler.co.uk wrote: 
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Hi all, 
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Just been trying to find information on what is different about 
the 
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KK 6502 (Atari) NOP adapter that makes it produce 8080 signatures 
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as opposed to the normal 6502 ones and I discovered that the 
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question has been posed before - not surprising I guess. 
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Just wandering if this mystery was ever solved and perhaps I'm not 
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looking in the right places? 
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I'm sure I once took down signatures from a working board using my 
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standard 6502 adapter but as always, when I want them, I'm damned 
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if I can find them so maybe I imagined it. 
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In case anyone hasn't a clue what I'm talking about, see the 
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footnote on page 14 of the PDF document "SigAnalNotes.pdf" that 
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ought to be all over the net but I can't find a link to it just 
yet! 
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The original TechTools list message where this was asked before is 
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here (with no answer): 
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http://www.vectorlist.org/TechTools/2002/10/0035.html 
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Thanks, 
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Martin. 
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Check the FTP archive on TTL (link below) for "Sig-Analy- 
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HPJMay77.pdf" this covers some Sig 
Analysis questions. I only have 
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info on the 6502, 6800 and Z80 NOP fixtures, which is at the rear 
of 
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"KK-Signature2.pdf" in the KurzKasch section of TTL. 
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For your question I would print off the last two pages of the 
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KK_Signature2.pdf, then pull up info on the 8080, find out what 
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instruction gives NOP, and then compare the pinout with the 6502. 
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John :-#)# 
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Re: [Techtoolslist] Atari 6502A NOP adapter

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