MC68HC908LJ12 Datasheet, PDF (63/413 Pages) Freescale Semiconductor, Inc – 8-bit microcontroller units

FLASH Memory (FLASH)
4.5 FLASH Page Erase Operation
Use the following procedure to erase a page of FLASH memory. A page
consists of 128 consecutive bytes starting from addresses $xx00 or
$xx80. The 48-byte user interrupt vectors area also forms a page. The
48-byte user interrupt vectors cannot be erased by the page erase
operation because of security reasons. Mass erase is required to erase
this page.
1. Set the ERASE bit and clear the MASS bit in the FLASH control
register.
2. Write any data to any FLASH address within the page address
range desired.
3. Wait for a time, t_nvs (at least 10µs).
4. Set the HVEN bit.
5. Wait for a time, t_erase (1ms).
6. Clear the ERASE bit.
7. Wait for a time, t_nvh (5µs).
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
executing code from the FLASH memory; the code must be executed
from RAM. While these operations must be performed in the order as
shown, but other unrelated operations may occur between the steps.
Technical Data
64
FLASH Memory (FLASH)
MC68HC908LJ12 — Rev. 2.1
Freescale Semiconductor