MC68HC908JB8 Datasheet, PDF (56/286 Pages) Motorola, Inc – MICROCONTROLLERS

FLASH Memory
4.5 FLASH Block Erase Operation
Use the following procedure to erase a block of FLASH memory. A block
consists of 512 consecutive bytes starting from addresses $X000,
$X200, $X400, $X600, $X800, $XA00, $XC00 or $XE00. Any block
within the 8,192 bytes user memory area ($DC00–$FBFF) can be
erased alone.
NOTE:
The 16-byte user vectors, $FFF0–$FFFF, cannot be erased by the block
erase operation because of security reasons. Mass erase is required to
erase this block.
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 address range of
the block to be erased.
3. Wait for a time, t_nvs (5 µs).
4. Set the HVEN bit.
5. Wait for a time t_erase (2 ms).
6. Clear the ERASE bit.
7. Wait for a time, t_nvh (5 µs).
8. Clear the HVEN bit.
9. After time, t_rcv (1 µs), the memory can be accessed in read mode
again.
NOTE:
Programming and erasing of FLASH locations cannot be performed by
code being executed from the FLASH memory. While these operations
must be performed in the order as shown, but other unrelated operations
may occur between the steps.
Technical Data
56
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
FLASH Memory
Freescale Semiconductor