Freescale Semiconductor, Inc.
Appendix: 68HC912D60A Flash EEPROM
22.8 Programming the Flash EEPROM
Programming the Flash EEPROM 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.
1. Set the PGM bit. This configures the memory for program
operation and enables the latching of address and data for
programming.
2. Write to any Flash address with any data within the row address
range desired.
3. Wait for a time, t
(min. 10µs).
NVS
4. Set the HVEN bit.
5. Wait for a time, t
(min. 5µs).
PGS
6. Write to the Flash address with data to the word desired to be
programmed. If BOOTP is asserted, an attempt to program an
address in the boot block will be ignored.
7. Wait for a time, t
(min. 30µs).
FPGM
8. Repeat steps 6 and 7 until all the words within the row are
programmed.
9. Clear the PGM bit.
10. Wait for a time, t
(min. 5µs).
NVH
11. Clear the HVEN bit.
12. After time, t (min 1µs), the memory can be accessed in read
RCV
mode again.
This program sequence is repeated throughout the memory until all data
is programmed. For minimum overall programming time and least
program disturb effect, the sequence should be part of an intelligent
operation which iterates per row.
Advance Information
404
68HC(9)12D60 — Rev 4.0
Appendix: 68HC912D60A Flash EEPROM
MOTOROLA
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