10 Aug
2007
10 Aug
'07
8:24 a.m.
woodelf wrote:
Chuck Guzis wrote:
I used a Ramtron FM20L08 128Kx8 3.3 volt part and some 74LVC buffers to
build an S-100 memory card. Works great, just like core. No special
logic of software needed. It's great to be able to turn on the machine
and have it run without booting from an external device. The 3.3v parts
are rated
for unlimited cycles.
Bob
Almost exactly like SRAM. You write individual
bytes, not the whole
device during a write cycle. Timing for write is about the same as
that for read. The 5V FM1808 (32Kx8) is a 70 nsec part. While not
blazingly fast by modern standards, it's good enough for most
"vintage" designs. Ramtron gives the number of read/write cycles as
being in excess of a trillion. Depending on your decoding logic for
WE\, you could use the same part for RAM and ROM. I've got a couple
here and I like them very much. 28-pin DIP package.
I still would like to see the 3.3 Volt part used as a *CORE* memory
replacement since I think it has unlimited R/W cycles.