Patent ID: 6044014
Filing Date: 2000-03-28
Classification: G11C

Abstract:
An electronic control unit comprising:an electrically erasable and rewritable nonvolatile read-only memory capable of erasing storage contents thereof block by block , and storing a control program and control data for a predetermined control object to be controlled;processing means for regulating the control object in normal operation according to the control program and the control data stored in the nonvolatile memory, and carrying out an erasure processing to erase a storage content in each of the blocks identified by an erasure command received from an external device when a predetermined rewrite condition is met and to replace the erased storage content with a new content received from the external device; andcounting means for counting the number of execution of the erasure processing as the number of rewrite of the nonvolatile memory and storing the counted number in a nonvolatile storage region,wherein the counting means counts the number of execution of the erasure processing only once even when the erasure processing is executed repeatedly for a plurality of the blocks during a period in which the processing means is held operative from an initial condition thereof.