I have a Midway grid board which is in constant reboots after it passes self-test. This uses the Athens board. Crusin' Exotica is also on the Athens board. I picked up an Exotica which is working fine. I did a rom swap Grid -> Crusin and get a mess of rom checksum errors. Digging around a touch I realized that they use an Altera Max EMP7128S at U29 as an address decoder. The Crusin boards appear to have a different memory map than the grid. I was able to rearrange some roms and combine four into two to get all but two roms to pass test. But it looks like there is no way to get the other two roms to come through. The Mame sources for this board imply that is should work but I was probing the chip select line (pin 11) at each of the sockets when the board did it's checksum on the problem roms. One socket triggers for just a moment and then the board fails the rom. The board has a 10 pin connector right next to the Altera chip, I am sure it's a jtag port. The Grid board has a hand written "AB" notation on the part id label which makes me believe they just flashed the board before they installed the roms. Problem is I have 0 experience with Altera parts and I don't have a clue how to try getting the code out (which could very well be protected). I am wondering if anyone here has any ideas on how to pull the code out on Grid and then reprogram the Exotica board. My only other alternative is to remove the chip from the exotica board and then pull the one from the grid and put onto the exotica. Doable if I am lucky. That's a really fine pitch 100 pin part. I tried arcade-service.com who say they work on these but they have been just shy of useless. David PS, oddly enough the crusin chips pass self-test on the grid board. I suspect they loaded both memory maps into the chip and then just select the correct one on boot using some configuration register. But as the grid didn't exist when they did the crusin boards.. _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com http://seven.pairlist.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
Problem is I have 0 experience with Altera parts and I don't have a clue how to try getting the code out (which could very well be protected). I am wondering if anyone here has any ideas on how to pull the code out on Grid and then reprogram the Exotica board. My only other alternative is to remove the chip from the exotica board and then pull the one from the grid and put onto the exotica. Doable if I am lucky. That's a really fine pitch 100 pin part.
The USB<->JTAG programmer/interface for Altera is the "USB Blaster". It's about $300 from Altera, but through the wonders of www.aliexpress.com you can pick one up for about $7 (not a typo) from China... Altera has a free download of their tool suite or just the programmer portion ("Quartus II Stand-Alone Programmer") which should be all you need to try to read the part. That having been said, I'd be flabbergasted if Atari didn't protect the fusemap. (Off the top of my head I don't recall if the Altera tools flat out *tell* you if the protection fuses are blown or if it just gives you garbage back.) The programmer is an easy test, so I'd probably try that first, but I suspect you're looking at a part swap (which really isn't bad with TQFP's as long as you have access to hot-air reflow-- or better yet, give it to someone that's done it before to do for you). The other thought that comes to mind is if the Altera is *just* being used for address decode since it has lots of IO and there's no internal state/register stuff going on, with the MAME memory map and some time tracing all the goes-intos and goes-outtas on the chip it may be possible to just write a new implementation of the functionality and make a works-alike JEDEC file you could throw down on the part instead. There's probably some places that could decap the CPLD and FIB the lock bit fuses, but I suspect you could buy a whole pile of boards for donor parts before you'd be at price parity. -Clay _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com http://seven.pairlist.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
participants (2)
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Clay Cowgill -
David Shoemaker