On 6 Jan 2012 at 19:59, Tony Duell wrote:
my solution, as others have suggested, was to use a
74F151
multiplexer. Select inputs fA, B, C) to the 3 input signals,
multiplexer output to the signal I was tryign to produce. The inputs
to the mux were, IIRC, pulled high by 1k reissotors (one of those SIL
packs) with links to ground to configure it. I think the prototype had
a pin header and push-on links, the 'production ones had links
soldered i nthe right positions.
Same idea, but inside-out. Uses an OC 3-to-8 demux rather than a
multiplexer. One pullup instead of a bunch. I thought the mux
solution too obvious.
AAR, not very challenging. Can you do a similar thing when the
inputs were of dissimilar logic families (you mentioned ECL) with a
single IC?
--Chuck