MC68HC908LD64 Datasheet, PDF (68/362 Pages) Freescale Semiconductor, Inc – Microcontrollers

FLASH Memory
4.5 FLASH Block Erase Operation
The minimum erase size for the FLASH memory is one block, and is
carried out by the block erase operation. For memory $0C00–$0FFF, a
block consists of 128 consecutive bytes starting from addresses $xx00
or $xx80. For memory $1000–$3FFF and $4000–$F9FF, a block
consists of 512 consecutive bytes starting from addresses $x000,
$x200, $x400, $x600, $x800, $xA00, $xC00, or $xE00.
NOTE:
The 32-byte user vectors, $FFE0–$FFFF, cannot be erased by the block
erase operation because of security reasons. Mass erase is required to
erase this block.
Use the following procedure to erase a block of FLASH memory:
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 block address
range desired.
3. Wait for a time, t_nvs (min. 5µs)
4. Set the HVEN bit.
5. Wait for a time, t_Erase (min. 10ms)
6. Clear the ERASE bit.
7. Wait for a time, t_nvh (min. 5µs)
8. Clear the HVEN bit.
9. After a time, t_rcv (min. 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.
Data Sheet
68
FLASH Memory
MC68HC908LD64 — Rev. 3.0
Freescale Semiconductor