We have discussed BCD numbers in which the bits have

Chapter 7, Problem P7.79

(choose chapter or problem)

We have discussed BCD numbers in which the bits have weights of 8, 4, 2, and 1. Another way to represent decimal integers is the 4221 code in which the weights of the bits are 4, 2, 2, and 1. The decimal integers, the BCD equivalents, and the 4221 equivalents are shown in Table P7.79. We want to design logic circuits to convert BCD codewords to 4221 codewords. a. Fill in the Karnaugh map for F, placing xs (dont cares) in the squares for BCD codes that do not occur in the table. Find the minimum SOP expression allowing the various xs to be either 1s or 0s to make the expression as simple as possible. b. Repeat (a) for G. c. Repeat (a) for H. d. Repeat (a) for I. Table P7.79. BCD, 4221, and excess-3 codewords for the decimal integers. BCD 4221 Excess-3 Decimal Codeword Codeword Codeword Integer ABCD FGHI WXYZ ..................................................... 0 0000 0000 0011 1 0001 0001 0100 2 0010 0010 0101 3 0011 0011 0110 4 0100 1000 0111 5 0101 0111 1000 6 0110 1100 1001 7 0111 1101 1010 8 1000 1110 1011 9 1001 1111 1100