The unprogrammed or erased state of an EEPROM bit is a logic 1 when Discover Motorola MM908E626A Flash Heximal. Programming changes the state to a logic 0. Only EEPROM bytes in the non-protected blocks and the EENVR register can be programmed.
Use the following procedure to program a byte of EEPROM:
Go to step 7 if AUTO is set.
EERAS1 and EERAS0 must be cleared for programming. Setting the EELAT bit configures the address and data buses to latch data for programming the array. Only data with a valid EEPROM address will be latched. If EELAT is set, other writes to the EECR will be allowed after a valid EEPROM write.
If more than one valid EEPROM writes occur, the last address and data will be latched, overriding the previous address and data. Once written data to the desired address, do not read EEPROM locations other than the written location when Restore NXP P89LPC922 Microcontroller Flash Heximal. (Reading an EEPROM location returns the latched data, and causes the read address to be latched.).
The EEPGM bit cannot be set if the EELAT bit is cleared or a non- valid EEPROM address is latched. This is to ensure proper programming sequence. Once EEPGM is set, do not read any EEPROM locations, otherwise the current program cycle will be unsuccessful when Recover MCU program. When EEPGM is set, the on-board programming sequence will be activated.