Advance Information MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
62 FLASH Memory MOTOROLA
FLASH Memory
4.7 FLASH Program/Read Operation
Programming of the FLASH memory is done on a row basis. A row
consists of 64 consecutive bytes starting from addresses $XX00,
$XX40, $0080 and $XXC0.
Use this step-by-step procedure to program a row of FLASH memory
(Figure 4-2 provides a flowchart representation):
1. Set the PGM bit. This configures the memory for program
operation and enables the latching of address and data for
programming.
2. Read from the FLASH block protect register.
3. Write any data to any FLASH address within the row address
range desired.
4. Wait for a time, tNVS, minimum of 10 µs.
5. Set the HVEN bit.
6. Wait for a time, tPGS, minimum of 5 µs.
7. Write data to the FLASH address to be programmed.
8. Wait for a time, tPROG, minimum of 30 µs.
9. Repeat step 7 and 8 until all the bytes within the row are
programmed.
10. Clear the PGM bit.(3)
11. Wait for a time, tNVH, minimum of 5 µs.
12. Clear the HVEN bit.
13. After a time, tRCV (minimum of 1 µs), the memory can be accessed
in read mode again.
This program sequence is repeated throughout th e memory until all da ta
is programmed.
NOTE: The time between each FLASH address change, or the time between
the last FLASH address programmed to clearing of the PGM bit, must
not exceed the maximum programming time, tPROG.