How exactly do PAL chips get programmed?
ard at p850ug1.demon.co.uk
Thu Nov 17 17:33:45 CST 2005
> So if I have the original code and know what chip it needs to be programmed
> on I might be in luck, otherwise there is little hope?
If you have the original, working, chip, it's worth sticking it into a
programmer that supports that chip and manufacturer and trying to read
Some manufactuerers did not copy-protect their PALs. For example, all the
PALs in the VAX 11/730 CPU are readable (for all they're the key to the
design). All PALs in every PERQ I've seen (including the AGW3300) are
readable. All PALs in the Torch XXX -- apart from those on the (3rd
party?) 68020 kludgeboard -- are readable. But then again, most PALs on
clone ISA boards are protected.
If the original chip is a HAL, you are out of luck. HAL == Hard Array
Logic, it's a mask-programmed equivalent to a PAL. I've never found one
that can be read out, I suspect the circuitry simply isn't there.
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