| 摘要 |
PROBLEM TO BE SOLVED: To provide a microcomputer which can debug a ROM(read only memory) program neither requiring an external memory nor producing a ROM again. SOLUTION: An EPROM (non-volatile memory) 20 is provided which exists on the same address space as a ROM 2 and is different in MSB(most significant bit) of the address, and a correction program corresponding to a part requiring correction of a program in the ROM 2, an auxiliary program required for use of the correction program, and an option signal are written in the EPROM 20, and the option signal in the EPROM 20 is received to change the address for reset release from the address of the ROM 2 to that of the EPROM 20 by an address bus MSB control register 17 and an address MSB selection circuit 18, and the auxiliary program in the EPROM 20 is executed, and the address is changed to the address of the ROM 2 by a clear instruction in the auxiliary program, and the program in the ROM 2 is read out. The correction program in the EPROM 20 is read out instead of the part requiring correction of this program.
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