FLASH Memory
FLASH Program/Read Operation
MC68HC908AB32 — Rev. 1.0 Technical Data
MOTOROLA FLASH Memory 63
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 is a flowchart representation):
NOTE:
In order to avoid program disturbs, the row must be erased before any
byte on that row is programmed.
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, t
nvs
(min. 10µs).
5. Set the HVEN bit.
6. Wait for a time, t
pgs
(min. 5µs).
7. Write data to the FLASH address to be programmed.*
8. Wait for a time, t
PROG
(min. 30µs).
9. Repeat step 7 and 8 until all the bytes within the row are
programmed.
10. Clear the PGM bit.*
11. Wait for a time, t
nvh
(min. 5µs).
12. Clear the HVEN bit.
13. After time, t
rcv
(min. 1µs), the memory can be accessed in read
mode again.
* The time between each FLASH address change, or the time between the last FLASH address
programmed to clearing PGM bit, must not exceed the maximum programming time, t
PROG
max.
This program sequence is repeated throughout the memory until all data
is programmed.
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