Errors cloning a PLD
Posted: 10 Nov 2011 12:16
We're trying to clone the AMD PALCE16V8Q/4 PLD used on an obsolete board that we've copied (we need spares, and not only has the manufacturer has stopped making it but they have no interest in supporting it either
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I keep getting the following when trying to read the device: "Bad contact at pin(s) 8 of programmed chip." - sometimes other pins are listed too. Same on a second device un-soldered from another board, though different pins cited. When I finally managed to get an error-free read, the buffer seems to be almost entirely '1's which looks wrong too.
Is this due to some copy protection scheme or is there another explanation? I don't really want to have to reverse-engineer the PLD as well as the PCB!
Cheers
Richard

I keep getting the following when trying to read the device: "Bad contact at pin(s) 8 of programmed chip." - sometimes other pins are listed too. Same on a second device un-soldered from another board, though different pins cited. When I finally managed to get an error-free read, the buffer seems to be almost entirely '1's which looks wrong too.
Is this due to some copy protection scheme or is there another explanation? I don't really want to have to reverse-engineer the PLD as well as the PCB!
Cheers
Richard