| 摘要 |
PURPOSE:To prevent data stored in a RAM from being lost after decision making operation by storing the data of the RAM in a register of a microprogram temporarily, reading and writing it in a specific address of the RAM, and detecting whether the read data coincides with the data in the register or not. CONSTITUTION:When a system power source VS is turned on, data stored in an address X of the RAM3 is read out and latched in the 1st register 11 of the CPU1, and this latched data is inverted and latched in the 2nd register 12 of the CPU1. This data in the 2nd register 12 is written in the address X of the RAM3 and the data is read out again. Then, it is decided whether the data read out of this RAM3 coincides with the data held in the 2nd register 12 or not and when so, the data latched in the 1st register 11 is written in the address X of the RAM3.
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