MC68HC708AS48 FREESCALE [Freescale Semiconductor, Inc], MC68HC708AS48 Datasheet - Page 69



Manufacturer Part Number
Advance Information
FREESCALE [Freescale Semiconductor, Inc]
Rev. 4.0
Follow this procedure to program a byte of EEPROM. Refer to
Control Timing
Electrically Erasable Programmable ROM (EEPROM)
1. Clear EERAS1 and EERAS0 and set EELAT in the EECR
2. Write the desired data to any user EEPROM address.
3. Set the EEPGM bit. (See Note c.)
4. Wait for a time, t
5. Clear the EEPGM bit.
6. Wait for the programming voltage time to fall, t
7. Clear EELAT bits. (See Note d.)
8. Repeat steps 1 through 7 for more EEPROM programming.
($FE1D). Set value of t
a. EERAS1 and EERAS0 must be cleared for programming.
b. Setting the EELAT bit configures the address and data buses
c. The EEPGM bit cannot be set if the EELAT bit is cleared and
d. Any attempt to clear both EEPGM and EELAT bits with a
Otherwise, you will be in erase mode.
to latch data for programming the array. Only data with a valid
EEPROM address will be latched. If another consecutive valid
EEPROM write occurs, this address and data will override the
previous address and data. 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.
a non-EEPROM write has occurred. This is to ensure proper
programming sequence. When EEPGM is set, the on-board
charge pump generates the program voltage and applies it to
the user EEPROM array. When the EEPGM bit is cleared, the
program 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.
for timing values.
Electrically Erasable Programmable ROM (EEPROM)
, to program the byte.
. (See Notes a and b.)
Functional Description
Advance Information

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