ONE-CHIP MICROCOMPUTER

摘要

PURPOSE:To alter the process contents of an OTPROM (one-time programmable ROM) by providing an internal memory to which process contents for error correction can be inputted from outside. CONSTITUTION:An address fetch part 4 when detecting a correction start address indicated by the internal memory 3 instructs data switching from the OTPROM 2 to the internal memory 3 to a data selector 5 with a select signal 14 and a central processing unit 1 is supplied thereafter with data written in the internal memory 3 from outside before the one-chip microcomputer starts operating. The internal memory 3 is supplied with an address signal from the central processing unit 1 through the address fetch part 4 and operates equally with a read of the OTPROM 2. While the central processing unit 1 reads the data out of the internal memory 3, an interruption inhibition signal 15 is outputted to the central processing unit 1 to inhibit interruption processing.