Date   : Tue, 01 Oct 2013 10:29:53 +0100 (WET-DST)
From   : bbcmicro@... (Peter Coghlan)
Subject: Doodah identification

>
>It has a 74'123 dual flip flop and a 74'00 quad nand gate. There's no
>analogue or sound stuff on it. It's a bit logic and one or two bits
>of state. It looks like it decodes the state of something and remembers
>it for something else.
>

Isn't the 123 a dual monostable? It can remember two bits, just not for very
long.

I don't recognise the board but I never got into the Risc stuff.  Maybe one of
the monostables stretches some signal to make it visible using the LED as some
sort of activity indicator?

The date codes on the ICs indicate it was probably made in 1997 or later.

Regards,
Peter Coghlan.