eeprom.asm

内部eeprom 模块 基于PICDEM 2PLUS pic16f877a芯片的开发板代码

#INCLUDE p16F877A.inc
ADDR EQU 20H; 写入寄存器地址
VALU EQU 21H;写入值
READCTR EQU 22H;读计数
WRITECTR EQU 24H;写计数
	ORG 00H
GOTO Main
Main
	BCF STATUS,RP1
	BCF STATUS, RP0 ;SELECT BANK0
	MOVLW 10H
	MOVWF ADDR;
	MOVLW 20H
	MOVWF VALU
	MOVLW 30H
	MOVWF FSR
	MOVLW 0FH
	MOVWF WRITECTR
 	MOVWF READCTR
	INCF READCTR
Write
	BSF STATUS,RP1
	BSF STATUS,RP0 ;bank3
	BTFSC EECON1,WR;写是否完成
	GOTO  $-1
	BCF STATUS,RP0
	BCF STATUS,RP1 ;bank0
	MOVF ADDR,W
	BSF STATUS,RP1 ;bank2
	MOVWF EEADR;写入地址
	BCF STATUS,RP1 ;bank0
	MOVF VALU,W;
	BSF STATUS,RP1 ;bank2
	MOVWF EEDATA;写入数据
	BSF STATUS,RP0 ;bank3
	BCF EECON1,EEPGD ;to data memory
	BSF EECON1,WREN;开写使能位
	BCF INTCON,GIE;关中断位
	MOVLW 55h
	MOVWF EECON2
	MOVLW 0aah
	MOVWF EECON2
	BSF EECON1,WR
	BTFSC EECON1,WR
	GOTO $-1;TO COMPLENT
	BSF INTCON,GIE
	BCF EECON1,WREN
	BCF STATUS,RP0
	BCF STATUS,RP1 ;bank0
	INCF ADDR,1
	DECF VALU,1
	DECFSZ WRITECTR ;all write,to read
	GOTO  Write
Read
	BCF STATUS,RP1
	BCF STATUS,RP0 ;bank0
	DECF ADDR ;next value
	MOVF ADDR,W
	BSF STATUS,RP1 ;bank2
	MOVWF EEADR
	BSF STATUS,RP0 ;bank3
	BCF EECON1,EEPGD
	BSF EECON1,RD
	BCF STATUS,RP0 ;bank2
	MOVF EEDATA,W
	BCF STATUS,RP1 ;bnak0
	MOVWF INDF ;存读出值
	INCF FSR
	DECFSZ READCTR
	GOTO Read
	GOTO Main
END