| 摘要 |
PURPOSE:To operate a ROM program while being corrected simply by utilizing a RAM mapped to the same address as a ROM and a correction CMOS memory. CONSTITUTION:A bus switching section 3 throws a bus 7 to the position of the ROM1. Then a CPU5 reads one word from the ROM1 and stores it temporarily, the bus switching section 3 is thrown to the position of the RAM2, and the CPU5 writes one word read from the ROm1 to the RAM2. Then whether or not the content of the ROM1 is written in the RAM2 is discriminated, the write to the RAM2 is performed finally and the content of the RAM2 is corrected based on the content of the CMOS memory 4. Thus, in using the corrected RAM in place of the ROM, the memory equal to the correction of the ROM is obtained substantially.
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