
Logic Circuit Design: Data Processing | 6.25
6.3.5 | Decimal-to-BCD Encoder
An encoder is a combinational logic function that has 10 (<2
n
) input lines and 4 output
lines. The 4 output lines generate the BCD code for the possible 10 decimal input lines. The
truth table of decimal-to-BCD encoder is given in Table 6.14.
TABLE 6.14 | Decimal-to-BCD encoder
Decimal
Value
Input Output
I
9
I
8
I
7
I
6
I
5
I
4
I
3
I
2
I
1
I
0
d
3
d
2
d
1
d
0
0 0 0 0 0 0 0 0 0 0 1 0 0 0 0
1 0 0 0 0 0 0 0 0 1 0 0 0 0 1
2 0 0 0 0 0 0 0 1 0 0 0 0 1 0
3 0 0 0 0 0 0 1 0 0 0 0 0 1 1
4 0 0 0 0 0 1 0 0 0 0 0 1 0 0
5 0 0 0 0 1 0 0 0 0 0 0 1 0 1
6 0 0 0 1 0 0 0 0 0 0 0 1 1 0
7 0 0 1 0 0 0 0 0 0 0 0 1 1 1
8 0 1