24c02.asm

基于51系列单片机的开机计数实验

;/*********************************************
; example program for 51 download board
;  @11.0592MHz
; 
; www.mcufan.com

;24c02的开机计数器，系统复位一次数码管加1
;*********************************************/
;
SDA24 EQU P1.7
SCLK24 EQU P1.6

ORG 0000H
AJMP MAIN
ORG 0030H
MAIN:
MOV A,#00H ;读地址
LCALL RD24
TT2: MOV 30H,A
CPL A
MOV P2,A ;送显示

MOV A,30H
INC A
MOV B,A
MOV A,#00H
LCALL WT24
AJMP $


RD24: PUSH ACC ;读24C02子程序。 
SETB SDA24 
CLR SCLK24 
CALL START24 
MOV A,#0A0H 
CALL SHIFT8 
CALL ACK 
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 
SETB SCLK24 
MOV C,SDA24 
MOV ACC.0,C 
CLR SCLK24 
DJNZ R7,RD000 
RET 
;-------------------------------
;写入24C02程序： 
WT24: PUSH ACC 
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
; -------------------------------
;开始条件
START24:CLR SDA24 
SETB SDA24
SETB SCLK24
CLR SDA24 
CLR SCLK24
RET

;停止条件
STOP: CLR SDA24 
SETB SCLK24
SETB SDA24
RET

;应答信号
ACK: SETB SCLK24 
CLR SCLK24
RET

;读、写数据
SHIFT8: MOV R7,#8 
SH01: RLC A
MOV SDA24,C
SETB SCLK24
CLR SCLK24
DJNZ R7,SH01
RET

DELAY2:
NOP
NOP
NOP
NOP
RET
END