On 2019-06-08 7:14 a.m., Piero Andreini via cctalk wrote:
desperately looking for jedec file of PAL 16L8 position U69 part # 1820-2991
I pulled the CPU board out of my HP9816 and was happy to see that the component in question is in a socket however there is a problem. The component in mine is a HAL16L8 note the "H" I found a datasheet and apparently in the early days of PALs at MMI you could do your development using PALs and then send the equations to MMI and they would produce a mask programmed semi custom chip with the same logic. The problem with this is it does not have a program ROM like a traditional PAL so you cannot extract a valid JEDEC from it, I confirmed this by dumping it as a PAL16L8 and then decompiling the JED file to extract the equations and they are junk, even just browsing the RAW JED looked suspect.
We can hope that it is all combinational logic and I can run trough all combinations of inputs and capture the output and we can develop equations that way as long as they did not do anything like use feedback to create registers as one person suggested could be done.
Paul.
