Electrically erasable and programmable non-volatile memory (eeprom),

Abstract

A microcomputer having an electrically erasable and programmable nonvolatile memory into which data is written without prolonging the data write processing time, even when a data read request is issued during the data write processing operation. The microcomputer includes a data erasing/writing/reading control circuit which coordinates the writing and reading of data to and from memory. The control circuit includes a timer for counting a predetermined number of counts during the data write process corresponding to the time period required to positively write data into the memory. If a data read request occurs during the data write process, the counting of the timer is suspended while the data is read out from the memory. After the data read process is completed, the data write process is resumed, and the timer continues counting toward the predetermined count from the count at which it was suspended. When the timer reaches the predetermined count, the data has been positively written into memory, and the data write process is terminated.