Wanted: M9312 ROMs

From: John Honniball <coredump_at_gifford.co.uk>
Date: Thu May 27 16:11:10 2004

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_at_gifford.co.uk
Received on Thu May 27 2004 - 16:11:10 BST

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