MC68HC908AB32 Datasheet, PDF (62/392 Pages) Motorola, Inc – HCMOS Microcontroller Unit

FLASH Memory
9. Clear the HVEN bit.
10. After a time, t_rcv (typ. 1µs), the memory can be accessed again in
read mode.
NOTE: While these operations must be performed in the order shown, other
unrelated operations may occur between the steps.
4.6 FLASH Mass Erase Operation
Use this step-by-step procedure to erase entire FLASH memory to read
as logic 1:
NOTE:
1. Set both the ERASE bit, and the MASS bit in the FLASH control
register.
2. Read from the FLASH block protect register.
3. Write any data to any FLASH address* within the FLASH memory
address range.
4. Wait for a time, t_nvs (min. 10µs)
5. Set the HVEN bit.
6. Wait for a time, t_MErase (min. 4ms)
7. Clear the ERASE bit.
8. Wait for a time, t_nvhl (min. 100µs)
9. Clear the HVEN bit.
10. After a time, t_rcv (min. 1µs), the memory can be accessed again in
read mode.
* When in Monitor mode, with security sequence failed (see 10.5 Security), write to the FLASH
block protect register instead of any FLASH address.
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 shown, other unrelated operations may
occur between the steps.
Technical Data
62
FLASH Memory
MC68HC908AB32 — Rev. 1.1
Freescale Semiconductor