Since I’m always on the lookout for PAL dumps, because I really hate it when a perfectly good PCB is useless because of one dodgy PAL, I have been looking at ways to allow people to make copies of protected PAL’s from their arcade boards.
Several people I know, who have quite a few arcade boards between them, also own a piece of test gear made by ABI, called a Board Master. These allow you to test chips in and out of circuit, the in-circuit part of the testing being extremely useful when fixing things. However these beasts also have a built in programming language, so here is the script and PC program to allow you to dump some of the PAL’s (combination logic ones only at the moment)
You need to download this file, inside which you will find a text file containing the script for the ABI side of things. Unless you know of a method to send files to the ABI from the PC (which I don’t yet – so please tell me), then you will need to key this into the ABI in program mode, and save it to a floppy disk to use in future.
You will also need to construct an RS232 cable to connect the ABI to your PC
|1. Go into program mode on your ABI
|2. Load the ‘paldump’ program (or whatever you called it when you saved it)
|3. Place the PAL to be examined into the internal socket, with pin 1 facing upwards. (may work in other positions, the ABI is meant to be clever about this sort of thing!)
|4. Load ‘hyperterminal’ or similar communications program on your PC
|5. set the PC to capture the text to a file
|6. run the program on the ABI. This should produce a file of information on the PC, which is a condensed dump of all input / output combinations
|7. once this has finished running (time depends upon number of inputs, worst case is 32 passes at the moment, which is about 5 minutes at 9600 baud) then close the capture file.
|8. on the PC, run the PD program to convert the data file to the equation file needed to recreate the PAL.
Command line > PD CAPTURE.TXT > OUTPUT.ABL
where CAPTURE.TXT is the filename you captured the output as, and redirect to OUTPUT.ABL to get the file to compile to produce a new .JED file.
PD is very heavily based on the paldump utility written by Charles – he wrote all of the decoding stuff, I just added some extra code so it can understand the ASCII dump generated by the ABI script. Sending the whole file in the format used by his pal cracker would take around 3 hours to run on the ABI!
See his page for more info, and to see what he is working on in the pal cracking department!