Date   : Wed, 04 Jul 2007 12:43:39 +0100 (BST)
From   : splodge@... (Richard Gellman)
Subject: Anyone recognise this board?

> http://www.anf.nildram.co.uk/board.html

I'd be hazzarding a guess here, but it looks like a ROM board with a
curiously complex address decode logic.

I would suggest the "two closely spaced IDCs" were actually an IC header,
and the ribbon plugged into a ROM socket.

The large chip at the top right appears to be a ROM of some sort, the rest
is all 74-series logic. The 74244s and 74245s are bus buffers, which is
curious for anything plugging into a ROM socket, and the presence of the
74138 3-to-8 decoder and the 74163 flip-flop are puzzling too.

The ROM in question is a 16K variety, which eliminates any sort of
"uber-ROM" board.

I can tell you it was made around 1984-85, and whatever the ROM it is, it
would appear that Acorn didn't get through many of them as it is from
1982.

If you're careful with checking the pinout, you should be able to read the
16K ROM in a BBC Micro (there may be a subtle variation in the chip select
pins).

-- Richard