452ee.asm

本源码的目的是让大家熟悉单片机内部EEPROM的读写方法

   		list	p=18f452
   		#include	<P18F452.INC>
;   
;---- 18F452 RAM LOCATIONS ------
Data_EE_Addr   EQU   0X000
Data_EE_Data   EQU   0X001
EEPROM_Buffer	equ		0x02
;--------VECTORS------------

		org		0x00   
        bra     START

;-------PROGRAM--------------
   
        org		0x20
START
        rcall   INIT
;
;----   Test the WRITE EEPROM Routine ----
;
		clrf	Data_EE_Addr	; set EEPROM start address at 0x00
		movlw	'0'				; Load a ASCII code "0" to W
		movwf	Data_EE_Data
EE_Write
		rcall	IN_DATA_EEW
		incf	Data_EE_Data,F	; 0x30+ N
		incf	Data_EE_Addr,F  ; Point to next EEPROM Address
		btfss	Data_EE_Addr,5	; Write 32 bytes ?
		goto	EE_Write
;
;----   Test the READ EEPROM Routine ----
;
		clrf	FSR0H			; Set RAM point to 0x010
		movlw	0x10
		movwf	FSR0L
;		
		clrf	Data_EE_Addr
EE_Read
		rcall	READ_EEPROM
		movwf	POSTINC0		; move W --> RAM then point + 1
;
		incf	Data_EE_Addr,F  ; Point to next EEPROM Address
		btfss	Data_EE_Addr,5	; Read 32 bytes ?
		goto	EE_Read
;
LSTOP      
        GOTO   LSTOP         
;
;------ INTERNAL EEPROM READ ------
;
READ_EEPROM
		movff	Data_EE_Addr,EEADR
;
;       bcf     INTCON,GIE  
		bcf		EECON1,EEPGD
		bsf		EECON1,RD
		movf	EEDATA,W
;       bsf     INTCON,GIE  
		return
;	
;----INTERNAL EEPROM WRITE-----
;
IN_DATA_EEW
         movff  Data_EE_Addr,EEADR
         movff  Data_EE_Data,EEDATA
;
         BCF   	 EECON1,EEPGD 
         BCF  	 EECON1,CFGS			; There are difference with data sheet
      
;         BCF     INTCON,GIE   
            
         BSF   	 EECON1,WREN 
;  
         MOVLW   0X55
         MOVWF   EECON2
         MOVLW   0XAA
         MOVWF   EECON2      
         BSF  	 EECON1,WR 
;         
;         BSF   INTCON,GIE 

LOOP1    BTFSS   PIR2, EEIF 
         GOTO    LOOP1 
;
         BCF  	 EECON1,WREN   
         BCF   	 PIR2,EEIF
      
         RETURN

;---------INITIAL----------------
INIT      
         BCF      PIR2,EEIF
         BCF      PIE2,EEIE
         RETURN
;--------------------------------
            END