The Sinclair QL Forum

So I've been digging a bit into EPROM's not having done much with them. I need to get one for my ZX Spectrum and I also have a spare Care Electronics ROM cartridge with nothing in it. I found an online site that built their own ROM cartrdige and uses a 27C128. Is that one that would work in that Care Electronic ROM cartridge?

Also, Looks like the EPROM is coded as follows given say: M27C128A-10F1

M = ??? what is that?

27 = designates 28 pins

C = CMOS

128 = KBits => 16 KBytes

A = ??? seems to be optional, what is that?

10 = 100 ns -- is that fast enough for QL?

F = DIP

1 = 0 to 70 celsius temperature range

(found this resource online that listed what some of these mean: https://www.batronix.com/shop/electroni ... mming.html)

I ask because AliExpress has the following choices: M27C128-10F1, M27C128-12F1, M27C128A-10F1, and M27C128A-12F1

I think M is the manufactures code - AM for instance is Advanced Micro Devices - M on it's own I think is SGS Thomson.

Likely the A after the part number denotes a specification improvement over the original device - likely it may program with a better algorithm (faster) than the original part.


I think for the QL either 100ns or 120ns parts should be fine - you can probably go slower than this - e.g. 200ns parts - as the access cycle is over several clocks of the 68000

I use this one a M27C4001 to replace the QL ROMs and it currently holds three sets of QL roms that I can switch before turn on. The modern C type are much faster so any TTL compatible one should work and the bigger they are the cheaper they seem to be because nobody wants EPROMs they are all using Flash ROMs now. Just tie the address lines you don't need on an EPROM that is bigger.