| 摘要 |
PURPOSE:To restore a runaway due to malfunction at the time of the writing of a program to a PROM by comparing the address that a program counter indicates with the final address recorded in a final address storage circuit. CONSTITUTION:While a program as a product whose final address is n/m is written in the PROM-incorporated microcomputer equipped with the program counter 1 indicating up to an address (n) and a PROM main body 2 whose final address is (n), the value n/m is written in the final address storage circuit 4 consisting of the PROM and logic. Then when the microcomputer is operated, a comparator circuit 3 compares the address of the program counter 1 with the value written in the final address storage circuit 4 at all times and outputs an address error signal when the address of the program counter 1 exceeds the value written in the final address storage circuit 4, and a state setting circuit 5 which has inputted the signal judges the runaway and is operated so as to restore the internal circuit state. |
