2 Nov
2010
2 Nov
'10
12:01 p.m.
On Tue, Nov 2, 2010 at 3:57 PM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
On 2010 Nov 2, at 10:41 AM, Dan Roganti wrote:
yes I agree
On Tue, Nov 2, 2010 at 3:19 PM, Brent Hilpert
<hilpert at cs.ubc.ca> wrote:
I'm not following you .. A,B,C are solutions for the earlier problem (any
74xx), the 04,08,54 solution is for the second problem (<=7486/SSI). The
AOIs qualify as SSI in my books.
Starting with those karnaugh maps (there's an error in the schematic),
there
is a solution with 10 packages:
? 1 ?7404
? 2 ?7408
? 7 ?74LS54
4 inverters to complement the inputs, 7 AOI for the segments, and 6 or 7
2-in AND to optimise and widen some of the AOI ANDs; utilisation of 9 &
1/6.
Based on the solutions and suggestions from the list, I drew up some
diagrams for the earlier problem:
? ? http://www3.telus.net/~bhilpert/tmp/7seg.gif
?A: 247,138 solution, suggested by several,
? ? optimised down to 5 14/16-pin packages
?B: 1-of-16 decoder with some optimisation, 5 packages (1 24-pin),
? ? suggested by James and Vincent, IIRC
?C: 247,253 data selectors solution suggested by Tony,
? ? 5 14/16-pin packages.
habl? SSI ? 