reading "secure" GAL chips

[Ray Carlsen]

I know they are almost a thing of the past but I wonder if there is
any way to extract the code from a protected GAL IC (example: GAL16V8A)
that has had its security bit set.
I repair mostly old Commodore 8 bit computers. There are a lot of
users of an after-market device called a RAMLink originally made by
Creative Micro Designs (CMD is now out of business) back in the 1980's,
and I was asked to repair a few of them. Turns out each one has four or
five GALs and they all are copy protected which makes repair of those
orphan devices impossible unless I can find a way to extract the code
from the chips in a working unit. Any hackers out there?

Ray

 

[petrus bitbyter]

I know they are almost a thing of the past but I wonder if there is
any way to extract the code from a protected GAL IC (example: GAL16V8A)
that has had its security bit set.
I repair mostly old Commodore 8 bit computers. There are a lot of
users of an after-market device called a RAMLink originally made by
Creative Micro Designs (CMD is now out of business) back in the 1980's,
and I was asked to repair a few of them. Turns out each one has four or
five GALs and they all are copy protected which makes repair of those
orphan devices impossible unless I can find a way to extract the code
from the chips in a working unit. Any hackers out there?

Ray

It was told to be software that presented series of input signals to the
PAL/GAL that searched for the fuse pattern rather then the logic. But I
never found it. Off course, combinatorial can be found easily. A pre
NT/2000/XP machine with a parallel printerport - preferable EPP - , a little
hardware and some old fashioned GWBASIC programming will do that job quite
easily. But the moment there are state machines inside, you're out of luck.
The only time I needed to reverse engineer a PAL like that, it was
relatively easy to find out the function from the schematic. I suppose it is
still the best thing to do. Off course, one can still go for the ultimate
PAL cracker but is it worth the time and the effort?

petrus bitbyter