27 May
2024
27 May
'24
10:25 a.m.
On Mon, May 27, 2024, 6:54 AM CAREY SCHUG via cctalk <cctalk(a)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.