Datasheet

PIC12F609/615/617/12HV609/615
DS41302D-page 34  2010 Microchip Technology Inc.
An example of the complete four-word write sequence
is shown in Example 3-2. The initial address is loaded
into the PMADRH and PMADRL register pair; the eight
words of data are loaded using indirect addressing.
EXAMPLE 3-2: WRITING TO FLASH PROGRAM MEMORY
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; This write routine assumes the following:
; A valid starting address (the least significant bits = '00')
; is loaded in ADDRH:ADDRL
; ADDRH, ADDRL and DATADDR are all located in data memory
;
BANKSEL PMADRH
MOVF ADDRH,W ; Load initial address
MOVWF PMADRH ;
MOVF ADDRL,W ;
MOVWF PMADRL ;
MOVF DATAADDR,W ; Load initial data address
MOVWF FSR ;
LOOP MOVF INDF,W ; Load first data byte into lower
MOVWF PMDATL ;
INCF FSR,F ; Next byte
MOVF INDF,W ; Load second data byte into upper
MOVWF PMDATH ;
INCF FSR,F ;
BANKSEL PMCON1
BSF PMCON1,WREN ; Enable writes
BCF INTCON,GIE ; Disable interrupts (if using)
BTFSC INTCON,GIE ; See AN576
GOTO $-2
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; Required Sequence
MOVLW 55h ; Start of required write sequence:
MOVWF PMCON2 ; Write 55h
MOVLW 0AAh ;
MOVWF PMCON2 ; Write 0AAh
BSF PMCON1,WR ; Set WR bit to begin write
NOP ; Required to transfer data to the buffer
NOP ; registers
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BCF PMCON1,WREN ; Disable writes
BSF INTCON,GIE ; Enable interrupts (comment out if not using interrupts)
BANKSEL PMADRL
MOVF PMADRL, W
INCF PMADRL,F ; Increment address
ANDLW 0x03 ; Indicates when sixteen words have been programmed
SUBLW 0x03 ; 0x0F = 16 words
; 0x0B = 12 words
; 0x07 = 8 words
; 0x03 = 4 words
BTFSS STATUS,Z ; Exit on a match,
GOTO LOOP ; Continue if more data needs to be written