C8051F360/1/2/3/4/5/6/7/8/9
Steps 3–8 must be repeated for each byte to be written
For block Flash writes, the Flash write procedure is only performed after the last byte of each block is writ-
ten with the MOVX write instruction. When writing to addresses located in any of the four code banks, a
Flash write block is four bytes long, from addresses ending in 00b to addresses ending in 11b. Writes must
be performed sequentially (i.e. addresses ending in 00b, 01b, 10b, and 11b must be written in order). The
Flash write will be performed following the MOVX write that targets the address ending in 11b. The Flash
write will be performed following the MOVX write that targets the address ending in 1b. If any bytes in the
block do not need to be updated in Flash, they should be written to 0xFF. The recommended procedure for
writing Flash in blocks is as follows:
Step 1. Disable interrupts.
Step 2. Set CHBLKW (register CCH0CN) to select block write mode.
Step 3. Write the first key code to FLKEY: 0xA5.
Step 4. Write the second key code to FLKEY: 0xF1.
Step 5. Set PSWE (register PSCTL) to redirect MOVX commands to write to Flash.
Step 6. Clear the PSEE bit (register PSCTL).
Step 7. Using the MOVX instruction, write the first data byte to the first block location (ending in
00b).
Step 8. Clear the PSWE bit to redirect MOVX commands to the XRAM data space.
Step 9. Write the first key code to FLKEY: 0xA5.
Step 10. Write the second key code to FLKEY: 0xF1.
Step 11. Set PSWE (register PSCTL) to redirect MOVX commands to write to Flash.
Step 12. Clear the PSEE bit (register PSCTL).
Step 13. Using the MOVX instruction, write the second data byte to the second block location
(ending in 01b).
Step 14. Clear the PSWE bit to redirect MOVX commands to the XRAM data space.
Step 15. Write the first key code to FLKEY: 0xA5.
Step 16. Write the second key code to FLKEY: 0xF1.
Step 17. Set PSWE (register PSCTL) to redirect MOVX commands to write to Flash.
Step 18. Clear the PSEE bit (register PSCTL).
Step 19. Using the MOVX instruction, write the third data byte to the third block location (ending in
10b).
Step 20. Clear the PSWE bit to redirect MOVX commands to the XRAM data space.
Step 21. Write the first key code to FLKEY: 0xA5.
Step 22. Write the second key code to FLKEY: 0xF1.
Step 23. Set PSWE (register PSCTL) to redirect MOVX commands to write to Flash.
Step 24. Clear the PSEE bit (register PSCTL).
Step 25. Using the MOVX instruction, write the fourth data byte to the last block location (ending
in 11b).
Step 26. Clear the PSWE bit to redirect MOVX commands to the XRAM data space.
Step 27. Re-enable interrupts.
Steps 3-26 must be repeated for each block to be written.
13.1.4. Non-volatile Data Storage
The Flash memory can be used for non-volatile data storage as well as program code. This allows data
such as calibration coefficients to be calculated and stored at run time. Data is written and erased using the
MOVX write instruction (as described in Section 13.1.2 and Section 13.1.3) and read using the MOVC
instruction. Note: MOVX read instructions always target XRAM.
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