MC68HC908MR8 Datasheet, PDF (58/372 Pages) Motorola, Inc – Microcontrollers

FLASH Memory
PGM — Program Control Bit
This read/write bit configures the memory for program operation.
PGM is interlocked with the ERASE bit such that both bits cannot be
set at the same time.
1 = Program operation selected
0 = Program operation unselected
4.2.3 FLASH Page Erase Operation
Use this step-by-step procedure to erase a page (64 bytes) of FLASH
memory to read as logic 1:
1. Set the ERASE bit and clear the MASS bit in the FLASH control
register.
2. Read the FLASH block protect register.
3. Write to any FLASH address with any data within the page
address range desired.
4. Wait for a time, t_NVS (minimum of 10 µs).
5. Set the HVEN bit.
6. Wait for a time, t_Erase (minimum of 1 ms).
7. Clear the ERASE bit.
8. Wait for a time, t_NVH (minimum of 5 µs).
9. Clear the HVEN bit.
10. After a time, t_RCV (typically 1 µs), the memory can be accessed in
read mode again.
NOTE:
While these operations must be performed in the order shown, other
unrelated operations may occur between the steps. Do not exceed t_NVH
maximum. See 21.7 Memory Characteristics.
Technical Data
58
FLASH Memory
MC68HC908MR8 — Rev 4.1
Freescale Semiconductor