Circuit Description

EEPROM write error detection is internal. No external circuits are involved. Microprocessor runs program to detect a write error when ever it writes to EEPROM. The only requirements are voltage and ground. This program runs even if voltage is out of operating range.

Microprocessor first writes information to a cell or address in EEPROM. Microprocessor then reads information and compares what was sent to the address. If they do not match after three consecutive attempts, microprocessor sets DTC B1656. When DTC is set, microprocessor finds another area to write information to. This new area becomes permanent area for storage until DTC is cleared. DTC will clear when microprocessor makes a successful write to the EEPROM.