On Mon, May 27, 2024, 6:54 AM CAREY SCHUG via cctalk <cctalk@classiccmp.org> wrote:
> Just curioius, as a much less techy person, are there sets of eproms that > are compatible for reading, but just require a different programming > regimen? Could the OP have used a different eprom that is easier to > program? > > If not, is the limitation pinout, so a header swapping pins could let a > different eprom be used? > > Just curioius, as a much less techy person, are there sets of eproms that are compatible for reading, but just require a different programming regimen? In general, yes, EPROMs of a given capacity usually all of the same pinout, but different device manufacturer specific programming algorithms. For a given capacity, a device manufacturer might even have multiple parts of that capacity with different algorithms. For example, an original version of a device, then a later A-suffix version with improved specifications and a different programming algorithm. (In earlier days there were some incompatible 16K-bit and 32K-bit EPROM pinouts. For example, be careful with TI TMS2516/TMS2716 TMS2532/TMS2732 EPROMs). > Could the OP have used a different eprom that is easier to program? In this case, the common 64K-bit 8Kx8 EPROM generic 2764 pinout has 28 pins. The Motorola MC68764 / MC68766 are uncommon 64K-bit EPROMs with only 24 pins, which I believe matches a 64K- bit mask ROM pinout instead. That limits the choices for drop in replacements.
