The first thing I want to do is confirm that the devices I program behave exactly as the originals.

The original MMI handbook shows the keyword FUNCTION TABLE followed by a list of pin names generating a truth table. Alas the Opal software does not recognise this keyword, and nor does GALASM.

Looks like the simplest way is to read the behaviour using a ROM socket adapter. I will need to make one for exercising PAL chips that are copy-protected.