MC68HC908BD48 Datasheet, PDF (59/290 Pages) Freescale Semiconductor, Inc – Microcontrollers

FLASH Memory
FLASH Program Operation
4.7 FLASH Program Operation
Programming of the FLASH memory is done on a row basis. A row
consists of 64 consecutive bytes starting from addresses $XX00,
$XX40, $XX80, 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. Write any data to any FLASH address within the row address
range desired.
3. Wait for a time, t_nvs (min. 5µs).
4. Set the HVEN bit.
5. Wait for a time, t_pgs (min. 10µs).
6. Write data to the FLASH address to be programmed.
7. Wait for time, t_PROG (min. 20µs).
8. Repeat step 6 and 7 until all the bytes within the row are
programmed.
9. Clear the PGM bit.
10. Wait for time, t_nvh (min. 5µs).
11. Clear the HVEN bit.
12. After time, t_rcv (min 1µs), 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 cannot be performed by
code being executed from the FLASH memory. While these operations
must be performed in the order shown, other unrelated operations may
occur between the steps. Do not exceed t_PROG maximum. See 21.15
Memory Characteristics.
MC68HC908BD48 — Rev. 1.0
MOTOROLA
FLASH Memory
Technical Data
59