Datasheet

PIC12F752/HV752
DS41576B-page 36 Preliminary  2011 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 four
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 ;Change value for different size write blocks
;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