| 摘要 |
PURPOSE:To change over to a preliminary system without passing through software by providing a present -use type memory part and a preliminary type memory part which have a register to show the present-use type or the preliminary type, executing the same action and rewriting the contents of the register when the trouble of the present-use type memory part occurs. CONSTITUTION:A control part 200, when the indication from a CPU is received from a line 201 by the part 200, selects a present-use type memory part 300 and a preliminary type memory part 400, reads the contents of registers 310 and 410 through lines 311 and 411 and judges the present-use type and the preliminary type. Next, Memory parts 300 and 400 are selected through a line 202, and the indicated action is simultaneously executed. When the trouble occurs at a present-use type memory part 300 on the way, the trouble is informed through a line 301 to the control part 200, and at the end of the action, the register 310 of the present-use memory part 300 is rewritten to the data to show the preliminary type through the line 311, further, the register 410 of the preliminary type memory part 400 is rewritten through the line 411 to the data to show the present-use type and the preliminary type memory part 400 is used as the present-use type.
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