at24c02.asm

以51系列单片机为核心

SDA24	EQU	P3.5
SCLK24	EQU	P3.4 
	ORG	0000H 
	AJMP	MAIN 
	ORG	0030H 
MAIN:CLR	P3.5	         ;打开写保护 
	MOV	DPTR,#TAB 
	MOV	A,#00H		;读地址 
	LCALL	RD24 
	CJNE	A,#10,TT 
TT:	JNC	TT1 
	AJMP	TT2 
TT1:	MOV	A,#00 
TT2:	MOV	30H,A 
	MOVC	A,@A+DPTR 
	CLR	P2.6		;开数码管 
	MOV	P0,A		;送显示 
	MOV	A,30H 
	INC	A 
	MOV	B,A 
	MOV	A,#00H 
	LCALL	WT24 
	AJMP	$ 
TAB:	DB	28H,7EH,0A2H,62H,74H,61H,21H,7AH,20H,60H 
RD24:  PUSH ACC		;读24C02子程序。 
        SETB SDA24 
        CLR SCLK24 
        CALL START24	;启动 
        MOV A,#0A0H 
        CALL SHIFT8 	;移位 
        CALL ACK	     ;响应 
        POP ACC 
        CALL SHIFT8 
        CALL ACK 
        CALL START24 
        MOV A,#0A1H 
        CALL SHIFT8 
        CALL ACK 
SETB SDA24 
        MOV R7,#8 
        CLR A 
        SETB SDA24 
  RD000:  RL A		;8个位 
SETB SCLK24 
        MOV C,SDA24 
        MOV ACC.0,C 
        CLR SCLK24 
        DJNZ R7,RD000 
        RET 
WT24:   PUSH ACC;写入24C02程序： 
        SETB SDA24 
        CLR SCLK24 
        CALL START24 
        MOV A,#0A0H 
        CALL SHIFT8 
        CALL ACK 
        POP ACC 
        CALL SHIFT8 
        CALL ACK 
        MOV A,B 
        CALL SHIFT8 
        CALL ACK 
        CALL STOP 
        CALL DELAY2 
        RET 
START24:CLR SDA24;开始条件 
        SETB SDA24 
        SETB SCLK24 
        CLR SDA24 
        CLR SCLK24 
        RET 
STOP:   CLR SDA24;停止条件 
        SETB SCLK24 
        SETB SDA24 
        RET 
ACK:    SETB SCLK24;应答信号 
        CLR SCLK24 
        RET 
SHIFT8: MOV R7,#8;读、写数据 
SH01:   RLC A 
        MOV SDA24,C 
        SETB SCLK24 
        CLR SCLK24 
        DJNZ R7,SH01 
        RET 
DELAY2:	NOP 
END