| 摘要 |
PROBLEM TO BE SOLVED: To automatically switch a current program to a spare boot program, even when the rewriting of a program ROM fails. SOLUTION: The initial starting device is provided with a current boot ROM 1, spare boot ROM 2, multiplexer 3, start detection circuit 5, switching circuit 6, reset signal generation circuit 7, timer circuit 8, and so on. When the circuit 5 detects that a CPU 4 has not started normally, a time circuit 8 monitors a detection output. When the CPU 4 has not started normally, even after the lapse of prescribed time from the start of operation, a clock completion signal for the circuits 7, 6 is generated, the circuit 6 generates a switching signal for selecting the spare boot ROM 2 and the circuit 7 resets the CPU 4 and the timer circuit 8, in a state with the boot program stored in the spare boot ROM 2 being validated for the CPU 4, so that the CPU 4 can be restarted automatically.
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