MC68HC908QC16_07 Datasheet, PDF (38/274 Pages) Freescale Semiconductor, Inc – Microcontrollers

Memory
2.6.3 FLASH Mass Erase Operation
Use the following procedure to erase the entire FLASH memory to read as a 1:
1. Set both the ERASE bit and the MASS bit in the FLASH control register.
2. Read the FLASH block protect register.
3. Write any data to any FLASH address⁽¹⁾ within the FLASH memory address range.
4. Wait for a time, t_NVS.
5. Set the HVEN bit.
6. Wait for a time, t_MErase.
7. Clear the ERASE and MASS bits.
NOTE
Mass erase is disabled whenever any block is protected (FLBPR does not
equal $FF).
8. Wait for a time, t_NVHL.
9. Clear the HVEN bit.
10. After time, t_RCV, 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, other unrelated operations may
occur between the steps.
CAUTION
A mass erase will erase the internal oscillator trim value at $FFC0.
1. When in monitor mode, with security sequence failed (see 18.3.2 Security), write to the FLASH block protect register in-
stead of any FLASH address.
MC68HC908QC16 • MC68HC908QC8 • MC68HC908QC4 Data Sheet, Rev. 3
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Freescale Semiconductor