MC68HC908AZ60 Datasheet, PDF (79/480 Pages) Motorola, Inc – HCMOS Microcontroller Unit

EEPROM-2
Functional Description
Functional Description
The 512 bytes of EEPROM-2 can be programmed or erased without an
external voltage supply. The EEPROM has a lifetime of 10,000
write-erase cycles. EEPROM cells are protected with a nonvolatile block
protection option. These options are stored in the EEPROM nonvolatile
register (EENVR2) and are loaded into the EEPROM array configuration
register after reset (EEACR2) or a read of EENVR2. Hardware interlocks
are provided to protect stored data corruption from accidental
programming/erasing.
The EEPROM-2 array will leave the factory in the erased state. All
addresses will be logic 1 and bit 4 of the EENVR2 register will be
programmed to 1 such that the full array can be available and
unprotected.
EEPROM
Programming
The unprogrammed state is a logic 1. Programming changes the state
to a logic 0. Only valid EEPROM bytes in the non-protected blocks and
EENVR2 can be programmed. It is recommended that all bits should
be erased before being programmed.
Follow this procedure to program a byte of EEPROM after first ensuring
the block protect feature is not set on the address block of the byte to be
programmed:
1. Clear EERAS1 and EERAS0 and set EELAT in the EECR2. (See
note A and B.)
2. Write the desired data to any user EEPROM address.
3. Set the EEPGM bit. (See note C.)
4. Wait for a time, t_EEPGM, to program the byte.
5. Clear EEPGM bit.
6. Wait for a time, t_EEFPV, for the programming voltage to fall.
7. Clear EELAT bits. (See note D.)
8. Repeat steps 1 to 7 for more EEPROM programming.
3-eeprom-2
MOTOROLA
EEPROM-2
MC68HC908AZ60 — Rev 2.0
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