30 Oct
2010
30 Oct
'10
12:52 a.m.
From: "Brent Hilpert": Thursday, October 28, 2010 3:55 PM
OK, I claim three solutions:
Assuming I haven't muffed the thing somewhere, I have a
solution using a 74154, a 7410, a 7411, and two 7420. That's
a total of 5 chips; no pull-ups or anything but straight TTL.
The only thing tricky about it is to calculate 1\3\7\ using one
of the 7411 gates, then use that as an input to widen both
the NAND gates for both upper left and lower left vertical
segments.
All 3 sections of the 7411 are used to widen (as needed) the NAND
gates being used to drive the actual segments. Segments default
"on" (low) unless their NAND gate is turned "off" (high) by some
active low output from the 74154.
Vince