27 May
2004
27 May
'04
9:11 a.m.
Joe R. wrote:
Doesn't the M9312 use Bipolar PROMs?
Yes, they are 74S571N, Am27S13 or 82S131N devices (2048 bit).
Does anyone know the part numbers of the blank ones or
have a source for
them or a programmer that can program them?
I have a programmer that can read and write them, a Stag PPZ with
Zm2000 EPROM module. The PROMs are 4 bits wide, which means that
the PDP-11's 16-bit words are stored in a somewhat strange manner.
In fact, some of the bits are stored inverted, too. The M9312
manual describes it all, though, and I've written some code to
un-mangle the data (which seemed to work).
--
John Honniball
coredump(a)gifford.co.uk