Erasing Flash Pages From Software; Figure 15.1. Flash Memory Map For Movc Read And Movx Write Operations - Silicon Laboratories C8051F12 Series Manual

C8051F120/1/2/3/4/5/6/7 C8051F130/1/2/3
COBANK = 0 COBANK = 1 COBANK = 2 COBANK = 3
Bank 0
Bank 0

Figure 15.1. Flash Memory Map for MOVC Read and MOVX Write Operations

15.1.2. Erasing Flash Pages From Software

When erasing Flash memory, an entire page is erased (all bytes in the page are set to 0xFF). The Flash
memory is organized in 1024-byte pages. The 256 bytes of Scratchpad area (addresses 0x20000 to
0x200FF) consists of two 128 byte pages. To erase any Flash page, the FLWE, PSWE, and PSEE bits
must be set to '1', and a byte must be written using a MOVX instruction to any address within that page.
The following is the recommended procedure for erasing a Flash page from software:
Step 1. Disable interrupts.
Step 2. If erasing a page in Bank 1, Bank 2, or Bank 3, set the COBANK bits (PSBANK.5-4) for
the appropriate bank.
Step 3. If erasing a page in the Scratchpad area, set the SFLE bit (PSCTL.2).
Step 4. Set FLWE (FLSCL.0) to enable Flash writes/erases via user software.
Step 5. Set PSEE (PSCTL.1) to enable Flash erases.
Step 6. Set PSWE (PSCTL.0) to redirect MOVX commands to write to Flash.
Step 7. Use the MOVX instruction to write a data byte to any location within the page to be
erased.
Step 8. Clear PSEE to disable Flash erases.
Step 9. Clear the PSWE bit to redirect MOVX commands to the XRAM data space.
Step 10. Clear the FLWE bit, to disable Flash writes/erases.
Step 11. If erasing a page in the Scratchpad area, clear the SFLE bit.
Step 12. Re-enable interrupts.
SFLE = 0
Bank 1 Bank 2 Bank 3
Bank 0 Bank 0 Bank 0
128k FLASH devices only.
Rev. 1.4
SFLE = 1
Internal
Address
0xFFFF
Undefined
0x8000
0x7FFF
0x00FF
Scratchpad
Areas (2)
0x0000
201