weird old ROM chips...

"Ian Field" schreef in bericht news:XF19q.122$ snipped-for-privacy@newsfe12.ams...

I know them too but the processors I'm talking about are build of bitslices or lower intergrated logic. They're not only pre PC but even pre micro.

petrus bitbyter

always

project!

up.

be

a=20

old

receptacles=20

bitslices=20

Ah yes, 2900 (TTL), COSMAC, and the likes. And there were a lot of hybrids as well with the micro doing the "slow" stuff.

?-)

On Thu, 01 Sep 2011 10:03:44 -0700, John Robertson put finger to keyboard and composed:

- Franc Zabkar

I should go through my stuff and sell off the ROM/EEROMS I have from yesteryears.

Jamie

Ah, 2K X 8...how did I miss that? OK, if you can find the Mostek 1975 PROM manual it covers the Mostek MK28000 which is a PMOS device using

-12/+5 and might well be similar or the same as yours.

Best guess for part numbers are:

EA4900C or EA4900L

Signetics has a PMOS 2K X 8 #2580 that might be close too...

Looking in my 1975 National Memory book I find the 24 pin MM4214/MM5214 (512 X 8) has a similar power layout (+5 & -12) with no ground/common connection! The book doesn't show the wiring, but does say the PMOS device as directly connected to TTL devices and each line has a 10pf cap.

John :-#)#

Weird. More chips I can't find specs for :-)