PROGRAM REWRITING DEVICE

PROBLEM TO BE SOLVED: To provide a program rewriting device capable of guaranteeing operation at restoring the power and normally downloading a program again even when an abnormal situation such as power-off occurs during the download of the program, and capable of normally controlling a system without requiring additional work even when hardware replacement such as board replacement is performed due to an unexpected situation. SOLUTION: A CPU 1 causes a program downloaded from a host device 5 to be written into a flash ROM 2, and causes data indicating that downloading and rewriting of the program is normally complete to be written into the flash ROM 2. During power restoration, the CPU 1 determines whether or not the data indicating that the downloading and rewriting of the data was normally complete has been written in the flash ROM 2; if it has not been written, the program is redownloaded. COPYRIGHT: (C)2005,JPO&NCIPI