On Mon, Feb 15, 2016 at 11:31 PM, John Robertson <j...@flippers.com> wrote: > Rick, if you want to archive these PROMs (highly recommended) you should be > able to find a Data I/O 29B and get one of the programming packs that > supports NS chips. I may have such a combination in my collection, but that > PROM is not listed in my DATA I/O library of readable parts.
They're not PROMs, they are masked ROMs, and there is *NO* equivalent PROM, so it's unlikely that there's any support for reading them on any PROM programmer. > Part of the > problem with the early PROMs is they needed a Sync or Clock signal to be > able to be read. The MM4221/5221 is fully static, so it doesn't have that particular problem. It's PMOS, and needs +5V and -12V supplies. The outputs are TTL-compatible, but the inputs technically are not, due to Vih min of 3.0V. Could be driven by TTL with a pullup resistor, or by CMOS.
