Datasheet

FLASH Memory (FLASH)

FLASH Mass Erase Operation

MC68HC908LJ24/LK24 — Rev. 2.1 Data Sheet

Freescale Semiconductor FLASH Memory (FLASH) 73

4.6 FLASH Mass Erase Operation

Use the following procedure to erase the entire FLASH memory:

1. Set both the ERASE bit and the MASS bit in the FLASH control

2. Read 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

(10µs).

5. Set the HVEN bit.

6. Wait for a time t

merase

(4ms).

7. Clear the ERASE bit.

8. Wait for a time, t

nvh1

(100µs).

9. Clear the HVEN bit.

10. 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

code being executed 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.