are four control inputs to the logic board, indicated by the blocks labeled A, B, C, and D. These inputs are driven by the CPU ... The CPU outputs listed, together with the inverters that are on each of the given lines, can be seen in Figure 15.12.
|Title||:||Microcomputer Operation, Troubleshooting, and Repair|
|Author||:||Robert T. Paynter|
|Publisher||:||Prentice Hall - 1986|