5211 code

Design a circuit which receives 5211 code and detects decimal numbers 0,2,4,6 and 8.
Sol: First prepare a truth table of the circuit as given below.

Decimal	5(A)	2(B)	1(C)	1(D)	Output
0	0	0	0	0	1
1	0	0	0	1	0
2	0	0	1	1	1
3	0	1	0	1	0
4	0	1	1	1	1
5	1	0	0	0	0
6	1	0	1	0	1
7	1	1	0	0	0
8	1	1	1	0	1
9	1	1	1	1	0

Minimization is done using Kmap and we get
f=(A*)(D*)+(A*)C+C(D*)
Now draw the logic diagram using NAND.
[Here "*" represents complement.i.e. A*=A complement]