TABLE OF CONTENTS We have seen in Chapter 2 that a large variety of codes are available for the same discrete elements of information, which results in the use of different codes for different digital systems. It is sometimes necessary to interface two digital blocks of different coding systems. A conversion circuit must be inserted between two such digital systems to use information of one digital system to other. Therefore, a code converter circuit makes two systems compatible when two systems use different binary codes.
To convert from one binary code A to binary code B, the input lines must provide the bit combination of elements as specified by A and the output lines must generate the corresponding bit combinations of code B. A combinational circuit consisting of logic gates performs this transformation operation. Some specific examples of code conversion techniques are illustrated in this chapter.
The bit combinations 4-bit binary code and its equivalent bit combinations of gray code are listed in the table in Figure 5.13. The four bits of binary numbers are designated as A, B, C, and D, and gray code bits are designated as W, X, Y, and Z. For transformation of binary numbers to gray, A, B, C, and D are considered as inputs and W, X, Y, and Z are considered as outputs. The Karnaugh maps are shown in Figures 5.14(a)-(d).
| Binary | Gray | ||||||
|---|---|---|---|---|---|---|---|
| A | B | C | D | W | X | Y | Z |
| 0 | 0 | 0 | 0 |
