PIC18F2331_10 Datasheet, PDF (92/392 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High-Performance PWM and A/D

PIC18F2331/2431/4331/4431
8.5.1
FLASH PROGRAM MEMORY WRITE
SEQUENCE
The sequence of events for programming an internal
program memory location should be:
1. Read 64 bytes into RAM.
2. Update data values in RAM as necessary.
3. Load Table Pointer with address being erased.
4. Do the row erase procedure (see Section 8.4.1
“Flash Program Memory Erase Sequence”).
5. Load Table Pointer with the address of the first
byte being written.
6. Write the first 8 bytes into the holding registers
with auto-increment.
7. Set the EECON1 register for the write operation
by doing the following:
• Set the EEPGD bit to point to program
memory
• Clear the CFGS bit to access program
memory
• Set the WREN bit to enable byte writes
8. Disable interrupts.
9. Write 55h to EECON2.
10. Write 0AAh to EECON2.
11. Set the WR bit. This will begin the write cycle.
12. The CPU will stall for the duration of the write
(about 2 ms using internal timer).
13. Execute a NOP.
14. Re-enable interrupts.
15. Repeat Steps 6-14 seven times to write
64 bytes.
16. Verify the memory (table read).
This procedure will require about 18 ms to update one
row of 64 bytes of memory. An example of the required
code is given in Example 8-3.
DS39616D-page 92
 2010 Microchip Technology Inc.