mc68hc08qa24 Freescale Semiconductor, Inc, mc68hc08qa24 Datasheet - Page 77

• Manufacturer Part Number: mc68hc08qa24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

MC68HC08QA24
Freescale SemiconductorElectrically Erasable Programmable Read-Only Memory (EEPROM)
In general, all bits should be erased before being programmed.
However, if program/erase cycling is of concern, this procedure can be
used to minimize bit cycling in each EEPROM byte. If any bit in a byte
must be changed from a 0 to a 1, the byte needs to be erased before
programming.
programming.
b. To ensure proper erasing sequence, the EEPGM bit cannot
c. Any attempt to clear both EEPGM and EELAT bits with a
Table 6-1. EEPROM Program/Erase Cycling Reduction
To Be Programmed
EEPROM Data
erase. Any attempts to read other EEPROM data will read the
latched data. If EELAT is set, other writes to the EECR will be
allowed after a valid EEPROM write.
be set if the EELAT bit is cleared and a non-EEPROM write
has occurred. Once EEPGM is set, the type of erase mode
cannot be modified. If EEPGM is set, the on-board charge
pump generates the erase voltage and applies it to the user
EEPROM array. When the EEPGM bit is cleared, the erase
voltage is removed from the array and the internal charge
pump is turned off.
single instruction will clear only EEPGM to allow time for
removal of high voltage from the EEPROM array.
Table 6-1
Electrically Erasable Programmable Read-Only Memory (EEPROM)
0
0
1
1
summarizes the conditions for erasing before
Before Programming
EEPROM Data
0
1
0
1
Programming?
Erase Before
Yes
No
No
No
Technical Data
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