Re: 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-----
>> 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
>>>>
>>>> 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 12:32:27 2009