In an electronic control system having a CPU, a RAM and an EEPROM, an original data stored in the EEPROM is written into the RAM to be updated in a control calculation processing of the CPU. If the updated data is the type which is to be written back into the EEPROM, a writing request is issued at the...http://www.google.com/patents/US6401163?utm_source=gb-gplus-sharePatent US6401163 - Apparatus and method for rewriting data from volatile memory to nonvolatile memory
