Re: Gottlieb / Q*bert scripts for the 9010A/9100
There is hardware for running an HP signature in the 9010a. I found this in the service manual (page 4 of 4 of the main board schematic, or something like that, there was no page number). Included in the calculation was a counter that counts the number of high to low transitions made by the incoming data bitstream.
Is this the Async clock module? (where you looking at the PDF from spies or do yo have a schematic?)
If this circuit is being used to calculate the sigs, it could be that this count value is being added back into the calculation to convolute things. If this is the case, the above solution won't work.
This could be tested by, finding two identical signatures, using different bytes, that created the same CRC, and then adding a third byte to see if they are both still equal.
2 identical signatures for the 9010A? we've got a collection of a paultry few. I did run across one the otherday but I'm pretty confident it was a typo. Alex Yeckley are you reading? Kev
On Wed, 8 May 2002 20:02:04 -0400, "Kev" <KKlopp@erols.com> wrote:
There is hardware for running an HP signature in the 9010a. I found this in the service manual (page 4 of 4 of the main board schematic, or something like that, there was no page number). Included in the calculation was a counter that counts the number of high to low transitions made by the incoming data bitstream.
Is this the Async clock module? (where you looking at the PDF from spies or do yo have a schematic?)
Yes, the one from spies. It's a small circuit all by itself on the page, and the bottom right corner of the page says "sh 4 of 4". You can recognize it by all the xor gates. -Zonn
Is this the Async clock module? (where you looking at the PDF from spies or do yo have a schematic?)
2 identical signatures for the 9010A? we've got a collection of a paultry few. I did run across one the otherday but I'm pretty confident it was a typo.
Alex Yeckley are you reading?
If I understand the question, I'm being asked if I know of any duplicate checksums or sigs? Yes I do - it was either Missile Command or Lunar Lander between different code revs, I don't recall the details. My theory was that Atari wanted to mix and match code revs of certain ROMs without altering the self-test (and hence requiring owners to swap more ROMs than was absolutely necessary). I think they probably just added a "catch-up" byte at the top of affected ROM to force the checksum/sig to whatever value they wanted. Maybe it was Asteroids - I have it written down, but not in any kind of format that I can search on. I haven't encountered any situations where - for example - a Pac Man checksum/sig just happened to be the same as a Sprint 2 checksum/sig. Alex ---- http://www.elektronforge.com ayeckley@elektronforge.com
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Alex Yeckley -
Kev -
Zonn