Building a PAL reader for TL866A
So I’m in the process of trying to reverse engineer some custom PALs from a Commodore Amiga Dataflyer 500. It would be ideal to read those PALs directly, however I don’t have a compatible PAL reading solutions. I’ve found some online but they are easily $800-$1200. So someone on a previous blog post commented about a potential solution that works with the TL866A eeprom reader.
So I decided to build this. Using an old school Radio shack 276-168B protoboard, wirewrap sockets, lots and lots of 30awg Kynar(?) wire, some resistors, and a cheap Amazon ZIF socket — I’ve created this monster.
I’m not convinced that, for whatever reason, this thing actually functions. I took great care in checking and double-checking my wiring. And I color-coded my connections to separate them.
The whole concept seems sensible. The PALs have a number of fixed input pins, a number of fixed output pins, and then some I/O pins which can vary based on setup. This adapter allows the TL866A to drive all of the pins via the number address lines, and then records that data values present on the potential output pins.
The pa.exe downloadable from the link above is what converts this EEPROM reading output file into a CUPL file that lists the equations for each output pin.
The results I’m getting seem at least partially correct, and I’m working with Bob to try to burn some new GALs and test them.
More to come on this…