MC68HC908LD64 Datasheet, PDF (69/362 Pages) Freescale Semiconductor, Inc – Microcontrollers

FLASH Memory
FLASH Mass Erase Operation
4.6 FLASH Mass Erase Operation
A mass erase operation erases an entire array of FLASH memory. The
MC68HC908LD64 contains two FLASH memory arrays, therefore, two
mass erase operations are required to erase all FLASH memory in the
device. Mass erasing the 13K-byte array, erases all FLASH memory
from $0800 to $3FFF. Mass erasing the 47,616-byte array, erases all
FLASH memory from $4000 to $FFFF.
Use the following procedure to erase an entire FLASH memory array:
1. Set both the ERASE bit, and the MASS bit in the FLASH control
register.
2. Write any data to any FLASH address within the FLASH memory
address range.
3. Wait for a time, t_nvs (5µs).
4. Set the HVEN bit.
5. Wait for a time, t_ERASE (10ms).
6. Clear the ERASE bit.
7. Wait for a time, t_nvhl (100µs).
8. Clear the HVEN bit.
9. After time, t_rcv (1µs)_, the memory can be accessed again in read
mode.
NOTE:
Programming and erasing of FLASH locations cannot be performed by
code being executed from the same FLASH array that is being
programmed or erased. While these operations must be performed in
the order as shown, but other unrelated operations may occur between
the steps.
MC68HC908LD64 — Rev. 3.0
Freescale Semiconductor
FLASH Memory
Data Sheet
69