Datasheet

PIC18F47J13 FAMILY
DS39974A-page 114 Preliminary  2010 Microchip Technology Inc.
EXAMPLE 7-3: WRITING TO FLASH PROGRAM MEMORY
MOVLW CODE_ADDR_UPPER ; Load TBLPTR with the base address
MOVWF TBLPTRU ; of the memory block, minus 1
MOVLW CODE_ADDR_HIGH
MOVWF TBLPTRH
MOVLW CODE_ADDR_LOW
MOVWF TBLPTRL
ERASE_BLOCK
BSF EECON1, WREN ; enable write to memory
BSF EECON1, FREE ; enable Erase operation
BCF INTCON, GIE ; disable interrupts
MOVLW 0x55
MOVWF EECON2 ; write 55h
MOVLW 0xAA
MOVWF EECON2 ; write 0AAh
BSF EECON1, WR ; start erase (CPU stall)
BSF INTCON, GIE ; re-enable interrupts
MOVLW D'16'
MOVWF WRITE_COUNTER ; Need to write 16 blocks of 64 to write
; one erase block of 1024
RESTART_BUFFER
MOVLW D'64'
MOVWF COUNTER
MOVLW BUFFER_ADDR_HIGH ; point to buffer
MOVWF FSR0H
MOVLW BUFFER_ADDR_LOW
MOVWF FSR0L
FILL_BUFFER
... ; read the new data from I2C, SPI,
; PSP, USART, etc.
WRITE_BUFFER
MOVLW D'64' ; number of bytes in holding register
MOVWF COUNTER
WRITE_BYTE_TO_HREGS
MOVFF POSTINC0, WREG ; get low byte of buffer data
MOVWF TABLAT ; present data to table latch
TBLWT+* ; write data, perform a short write
; to internal TBLWT holding register.
DECFSZ COUNTER ; loop until buffers are full
BRA WRITE_BYTE_TO_HREGS
PROGRAM_MEMORY
BSF EECON1, WREN ; enable write to memory
BCF INTCON, GIE ; disable interrupts
MOVLW 0x55
Required MOVWF EECON2 ; write 55h
Sequence MOVLW 0xAA
MOVWF EECON2 ; write 0AAh
BSF EECON1, WR ; start program (CPU stall)
BSF INTCON, GIE ; re-enable interrupts
BCF EECON1, WREN ; disable write to memory
DECFSZ WRITE_COUNTER ; done with one write cycle
BRA RESTART_BUFFER ; if not done replacing the erase block