XC912BC32CFU8 Motorola Semiconductor Products, XC912BC32CFU8 Datasheet - Page 103

• Manufacturer Part Number: XC912BC32CFU8
• Description: M68HC12B Family Data Sheet
• Manufacturer: Motorola Semiconductor Products

M68HC12B Family — Rev. 8.0
MOTOROLA
NOTE:
EELAT — EEPROM Latch Control Bit
When EELAT is set, the entire EEPROM is unavailable for reads. Therefore, no
program residing in the EEPROM can be executed while attempting to program
unused EEPROM space. Care should be taken that no references to the EEPROM
are used while programming. Interrupts should be turned off if the vectors are in
the EEPROM. Timing and any serial communications must be done with polling
during the programming process.
EEPGM — Program and Erase Enable Bit
The BULKP, BYTE, ROW, ERASE, and EELAT bits cannot be changed when
EEPGM is set. To complete a program or erase, a write to clear EEPGM and
EELAT bits is required before reading the programmed data. A write to an
EEPROM location has no effect when EEPGM is set. Latched address and data
cannot be modified during program or erase.
A program or erase operation should follow this sequence:
To program/erase more bytes or words without intermediate EEPROM reads, only
write EEPGM = 0 in step 5, leaving EELAT = 1, and jump to step 2.
1. Write BYTE, ROW, and ERASE to the desired value;
2. Write a byte or an aligned word to an EEPROM address.
3. Write EEPGM = 1.
4. Wait for programming (
5. Write EEPGM = 0 and EELAT = 0.
Read anytime. Write anytime if EEPGM = 0.
BYTE, ROW, ERASE, and EELAT bits can be written simultaneously or in any
sequence.
The EEPGM bit can be set only after EELAT has been set. When an attempt is
made to set EELAT and EEPGM simultaneously, EEPGM remains clear but
EELAT is set.
0 = EEPROM set up for normal reads
1 = EEPROM address and data bus latches set up for programming or
0 = Disables program/erase voltage to EEPROM
1 = Applies program/erase voltage to EEPROM
write EELAT = 1.
erasing
EEPROM
t
PROG
) or erase (
t
Erase
) delay time.
EEPROM Control Registers
Data Sheet
EEPROM
103