PIC18LF4331 datasheet(92/392 Pages) MICROCHIP

92 / 392 page

PIC18F2331/2431/4331/4431

DS39616D-page 92

 2010 Microchip Technology Inc.

8.5.1

FLASH PROGRAM MEMORY WRITE

SEQUENCE

The sequence of events for programming an internal

program memory location should be:

Read 64 bytes into RAM.

Update data values in RAM as necessary.

Load Table Pointer with address being erased.

Do the row erase procedure (see Section 8.4.1

“Flash Program Memory Erase Sequence”

Load Table Pointer with the address of the first

byte being written.

Write the first 8 bytes into the holding registers

with auto-increment.

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

Disable interrupts.

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.

PIC18LF4331 Datasheet(PDF) 92 Page - Microchip Technology