| 摘要 |
PURPOSE:To prevent the runaway of a program by transmitting an error signal to a microcomputer by an interruption, in case when an address signal by a progress of the program has become outside a prescribed range. CONSTITUTION:An address holding circuit 13, an address comparing circuit 12 and an address holding circuit 16 are provided on a CPU 1, and an address signal 10 for a code access is inputted to the circuit 12 by a status signal 11, compared with an address 14 which a program which has been set in advance to the circuit 13 passes through, and if it is outside the range, an error signal 15 is generated. Also, by connecting the signal 10 to the circuit 16, an address of one or several pieces before is held, and when the signal 15 is received, the CPU 1 inputs an address before an error occurs, as a data 17 through the circuit 16, and a runaway prevention processing is executed. |
