MC68HC708AS48 FREESCALE [Freescale Semiconductor, Inc], MC68HC708AS48 Datasheet - Page 71

• Manufacturer Part Number: MC68HC708AS48
• Description: Advance Information
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

MC68HC708AS48
MOTOROLA
—
Rev. 4.0
In general, all bits should be erased before being programmed.
However, if program/erase cycling is of concern, the following 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.
before programming.
Electrically Erasable Programmable ROM (EEPROM)
EEPROM Data To Be
b. To ensure proper erasing sequence, the EEPGM bit cannot
c. Any attempt to clear both EEPGM and EELAT bits with a
Programmed
Table 6-1. EEPROM Program/Erase Cycling Reduction
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.
0
0
1
1
Table 6-1
EEPROM Data Before
Electrically Erasable Programmable ROM (EEPROM)
Programming
summarizes the conditions for erasing
0
1
0
1
Functional Description
Programming?
Erase Before
Advance Information
Yes
No
No
No
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