PIC18F87J90 Datasheet, PDF (96/450 Pages) Microchip Technology – 64/80-Pin, High-Performance Microcontrollers with LCD Driver and nanoWatt Technology

PIC18F87J90 FAMILY
EXAMPLE 7-3: WRITING TO FLASH PROGRAM MEMORY
ERASE_BLOCK
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BSF
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BSF
MOVLW
MOVWF
CODE_ADDR_UPPER
TBLPTRU
CODE_ADDR_HIGH
TBLPTRH
CODE_ADDR_LOW
TBLPTRL
EECON1, WREN
EECON1, FREE
INTCON, GIE
55h
EECON2
0AAh
EECON2
EECON1, WR
INTCON, GIE
D'16'
WRITE_COUNTER
RESTART_BUFFER
FILL_BUFFER
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
...
D'64'
COUNTER
BUFFER_ADDR_HIGH
FSR0H
BUFFER_ADDR_LOW
FSR0L
WRITE_BUFFER
MOVLW
MOVWF
WRITE_BYTE_TO_HREGS
MOVFF
MOVWF
TBLWT+*
D’64
COUNTER
POSTINC0, WREG
TABLAT
PROGRAM_MEMORY
Required
Sequence
DECFSZ COUNTER
BRA
WRITE_BYTE_TO_HREGS
BSF
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BSF
BCF
EECON1, WREN
INTCON, GIE
55h
EECON2
0AAh
EECON2
EECON1, WR
INTCON, GIE
EECON1, WREN
; Load TBLPTR with the base address
; of the memory block, minus 1
; enable write to memory
; enable Erase operation
; disable interrupts
; write 55h
; write 0AAh
; start erase (CPU stall)
; re-enable interrupts
; Need to write 16 blocks of 64 to write
; one erase block of 1024
; point to buffer
; read the new data from I2C, SPI,
; USART, etc.
; number of bytes in holding register
; get low byte of buffer data
; present data to table latch
; write data, perform a short write
; to internal TBLWT holding register.
; loop until buffers are full
; enable write to memory
; disable interrupts
; write 55h
; write 0AAh
; start program (CPU stall)
; re-enable interrupts
; disable write to memory
DECFSZ WRITE_COUNTER
BRA
RESTART_BUFFER
; done with one write cycle
; if not done replacing the erase block
DS39933D-page 96
 2010 Microchip Technology Inc.