Flash memory microcomputer, data writing method for the flash memory built in the microcomputer, and, writing the program data to the flash memory

Flash memory microcomputer includes two memory blocks to be updated in order. Each memory block includes a plurality of slots for storing block management information and data. Block management information includes an update counter indicating the order in which data is updated. Each of the plurality of slots, the updated data has its writing completed that write complete flags and (WCM), for a plurality of slots, the data in a predetermined order is updated, the two memory blocks a memory block detecting means for detecting the most recently updated memory block based on the updated counter (S14), the detection memory block of the memory block detecting means, the most recently data in consideration of the predetermined order and write completion flag writing and a slot detecting means for detecting (S15 to S17) a slot completed.