| 摘要 |
PURPOSE:To check on memory contents securely through simple constitution, by checking memories according check programs from other memories. CONSTITUTION:In ROMs 2, 3-, the control program of a microprocessor 1 is stored. According to the state of an FF14 after the power source is turned on, a check program 11 is read out of the ROM2 through a processor 1 and through the processing of the processor 1 following said program, contents of the ROMs 3, 4- are compared with check data in the ROM2 to decide on whether there is an error in the ROMs 3, 4- or not according to the coincidence or uncoincidence. Then, a similar check on the ROM2 is made by the check program 12 in the ROM 3 according to variation in the output of the FF14. Therefore, the check on memory contents is made securely by the constitution which eliminates the need for a parity bit memory and its peripheral circuit. |
