Question

5.(20 PTS) A combinational circuit converts an Excess-3 input (ABCD) into a Hexidecimal output displayed on a seven segment display (a,b,c,d,e,f,g). All invalid combinations (negative numbers) are don't cares. . E Represent 6 as and 9 as I - algla di 16 Represent hexadecimal letters in capital letters if possible. Show how you represent the letters with seven segment indicators as above for 6 and 9. Show how you would implement each segment of the display using 2 74LS138 decoders and a minimum number of necessary external gates if any. Block diagrams showing only the necessary connections are acceptable (ignore Vcc and ground). List the part numbers for the external gates. List the total number of integrated circuits required. Use only techniques covered in class to receive credit.

NOTE: PLEASE USE FEWEST NUMBER OF COMPONENTS POSSIBLE FOR EACH IMPLEMENTATION?

Answer 1

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Optinized Boolean Expressions for each output! ام و آه B = (13+ni) (na trz +ño) in, that.) (M2 +1, +no) B: nznz logo 1 = (13+N2) (M₂+1, ) (m3 +n +ño) (13 + ñ tñi) nznz 900 0 11 D20 ooolloo 1 - (n2 +no) Ing+n) Ing+rt) (ngan, +ño) 10 10 10 CS Scanned F T Scanned With CamScandler

10402_IL = (13 + + n) (n3 +5, +no) (n2 tn, tho). (53 +1₂ + n) (na tn 2 tn, tão) = (n2 th, tno) (n3+7, +no) 10 11 ool Finn n od Lo TT | | 21 | 1, CA, 10, 11) (+1, tr.) (13 +52 +0,) (53 +₂ +ni) Ginoo old Oo oo 1000 = (ng the +ni) (ng tña +no) (13 + H2 + 7) thg & Mathild Scanned with CamScanner EN

Here one input line (o) is used to crwne disable the the de condens. When decoude HS. When D=0 the top de Caldes is enabled and the other is disabled . Thus the bobom decorder outputs are all 1s, and the top light outputs generate minte sims 0000 to 0!!!. When O=1, the enable conditions are reversed and thus boltom decorder outputs generate minterms 1000 to lu, while the outputs of the top decomdes are all 18. Yo no HA 25 € 7415138 44 ny Stanned with