17 Apr
2006
17 Apr
'06
6:48 p.m.
Tony Duell wrote:
[attributions lost]
What was more amusing was two different versions -- "with tails" and
without! :>
Me, I wish
they'd made those common TTL 7-segment decoder/driver chips
display something more like hex when you got into codes past 9...
I think the display patters for 1010-1111 for the 7447A (I assume that's
one of the chips you were refereing to) came naturally from the logic
used to decode 0000-1001, along with the fact that 1111 should be a
blank. Rememebr when that chip was designed, every gate cost money :-),
it certainly isn't a 16 word * 7 bit ROM. That said, I think it is a pity there wasn't a
later TTL 7 segment
decoder chip (say a 74LS547 or something) that did display 0-F as you
might expect.
*Something* does this -- though I may have been driving LCD's
at the time (thus CMOS parts). But, I remember a 7441 (though
what I used it for I am unsure... :< )