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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