Datasheet

EEPROM
Technical Data MC68HC908AB32 — Rev. 1.1
74 EEPROM Freescale Semiconductor
These bits are effective after a reset or a read to EENVR register. The
block protect configuration can be modified by erasing/programming the
corresponding bits in the EENVR register and then reading the EENVR
register.
5.9 EEPROM Programming and Erasing
The unprogrammed or erased state of an EEPROM bit is a logic 1. The
factory default for the EEPROM array is $FF for all bytes.
The programming operation changes an EEPROM bit from logic 1 to
logic 0 (programming cannot change a bit from logic 0 to a logic 1). In a
single programming operation, the minimum EEPROM programming
size is zero bits; the maximum is eight bits (one byte).
The erase operation changes an EEPROM bit from logic 0 to logic 1. In
a single erase operation, the minimum EEPROM erase size is one byte;
the maximum is the entire EEPROM array.
For each EEPROM byte, the write/erase endurance is 10,000 cycles.
One write/erase cycle is defined as: a maximum of eight programming
operations on the same byte followed by an erase operation of the that
byte. Therefore, it is possible to program a byte, bit by bit to logic 0
before requiring an erase on that byte.
NOTE: Although programming a bit (from 0 or 1) with a logic 1 does not change
the state of that bit, it is still regarded as a programming operation. That
is, if the same byte is programmed eight times (with any value), that byte
must be erased before it can be successfully programmed again.
Table 5-1. EEPROM Array Address Blocks
Block Number (EEBPx) Address Range
EEBP0 $0800–$087F
EEBP1 $0880–$08FF
EEBP2 $0900–$097F
EEBP3 $0980–$09FF