MC68HC908GZ16 Datasheet, PDF (44/314 Pages) Motorola, Inc – Microcontrollers

Memory
10. Clear the PGM bit.⁽¹⁾
11. Wait for a time, t_NVH (minimum 5 µs).
12. Clear the HVEN bit.
13. After time, t_RCV (typical 1 µs), the memory can be accessed in read mode again.
This program sequence is repeated throughout the memory until all data is programmed.
NOTE
Programming and erasing of FLASH locations can not be performed by
code being executed from the same FLASH array.
NOTE
While these operations must be performed in the order shown, other
unrelated operations may occur between the steps. Care must be taken
within the FLASH array memory space such as the COP control register
(COPCTL) at $FFFF.
NOTE
It is highly recommended that interrupts be disabled during program/ erase
operations.
NOTE
Do not exceed t_PROG maximum or t_HV maximum. t_HV is defined as the
cumulative high voltage programming time to the same row before next
erase. t_HV must satisfy this condition:
t_NVS + t_NVH + t_PGS + (t_PROG x 32) ≤ t_HV maximum
Refer to 21.15 Memory Characteristics.
NOTE
The time between programming the FLASH address change (step 7 to step
7), or the time between the last FLASH programmed to clearing the PGM
bit (step 7 to step 10) must not exceed the maximum programming time,
t_PROG maximum.
CAUTION
Be cautious when programming the FLASH array to ensure that
non-FLASH locations are not used as the address that is written to when
selecting either the desired row address range in step 3 of the algorithm or
the byte to be programmed in step 7 of the algorithm. This applies
particularly to $FFD4–$FFDF.
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 1
44
Freescale Semiconductor