kaijijs.asm

基于C51的24c02开机计数设计

   SDA24   EQU P2.3
   SCLK24  EQU P2.2

           ORG 0000H
           AJMP MAIN
           ORG 0030H

MAIN:      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 P3.7 ;开数码管
           MOV P0,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

TAB:       DB 0C0H,0F9H,0A4H,0B0H,99H,92H,82H,0F8H,80H,90H


           END