C8051F960-B-GM Datasheet, PDF (245/492 Pages) Silicon Laboratories – Ultra Low Power 128K, LCD MCU Family

C8051F96x
9. Restore previous interrupt state.
Steps 4–7 must be repeated for each 1024-byte page to be erased.
Notes:
1. Flash security settings may prevent erasure of some flash pages, such as the reserved area and the page
containing the lock bytes. For a summary of flash security settings and restrictions affecting flash erase
operations, please see Section “18.3. Security Options” on page 247.
2. 8-bit MOVX instructions cannot be used to erase or write to flash memory at addresses higher than 0x00FF.
18.1.3. Flash Write Procedure
A write to flash memory can clear bits to logic 0 but cannot set them; only an erase operation can set bits
to logic 1 in flash. A byte location to be programmed should be erased before a new value is written.
The recommended procedure for writing a single byte in flash is as follows:
1. Save current interrupt state and disable interrupts.
2. Set the PSWE bit (register PSCTL).
3. Clear the PSEE bit (register PSCTL).
4. If writing to an address in Banks 1, 2, or 3, set the COBANK[1:0] bits (register PSBANK) for the
appropriate bank.
5. Ensure that the flash byte has been erased (has a value of 0xFF).
6. Write the first key code to FLKEY: 0xA5.
7. Write the second key code to FLKEY: 0xF1.
8. Using the MOVX instruction, write a single data byte to the desired location within the 1024-byte
sector.
9. Clear the PSWE bit.
10. Restore previous interrupt state.
Steps 2–8 must be repeated for each byte to be written.
Notes:
1. Flash security settings may prevent writes to some areas of flash, such as the reserved area. For a summary of
flash security settings and restrictions affecting flash write operations, please see Section “18.3. Security
Options” on page 247.
2. 8-bit MOVX instructions cannot be used to erase or write to flash memory at addresses higher than 0x00FF.
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