小弟把DS1302的原程序貼出來供大家參考  
  
   LIST P=16F877
 INCLUDE
LP1  EQU 20H
LP2  EQU 21H
TRBUF EQU 22H
BUFF EQU 23H

M  EQU 26H
N  EQU 27H
FLAG EQU 38H
LP0  EQU 3AH
 
SS  EQU 30H 
FEN  EQU 31H
HH  EQU 32H
DAT  EQU 33H
YUE  EQU 34H
ZHOU EQU 35H
YEAR EQU 36H

E口為時鐘連接口

RST  EQU 02H
IO  EQU 01H
CLK  EQU 00H
 
 

 ORG 00H
 NOP
 GOTO MAIN 
MAIN
 
 BCF STATUS,RP1
 BSF STATUS,RP0
 MOVLW 00H
 MOVWF TRISE  
  MOVLW 03H
  MOVWF ADCON1
 BCF STATUS,RP1
 BCF STATUS,RP0
 BCF PORTE,CLK
 BCF PORTE,RST
 MOVLW 8EH
 MOVWF TRBUF 
 BSF PORTE,RST
 CALL CMD
 BCF PORTE,CLK 
 MOVLW 00H
 MOVWF TRBUF
 CALL CMD  
 BCF PORTE,RST
 BCF PORTE,CLK
 MOVLW 90H
 MOVWF TRBUF
 BSF PORTE,RST
 CALL CMD
 BCF PORTE,CLK
 MOVLW B'10100101' 
 MOVWF TRBUF
 CALL CMD  
 BCF  PORTE,CLK
 BCF  PORTE,RST
 MOVLW 81H
 MOVWF TRBUF
 BSF  PORTE,RST
 CALL CMD
 CALL RD3
 BTFSC FLAG,7
;檢測時鐘是否運(yùn)行
 CALL WRTDS  
 GOTO READTIME
;寫入時鐘數(shù)據(jù)00秒35分10時6月15號周204年 
DS1302INITAL
 BCF  STATUS,RP0
 BCF  STATUS,RP1
  MOVLW 30H
 MOVWF SS
 MOVLW 44H
 MOVWF FEN
 MOVLW 14H
 MOVWF HH
 MOVLW 06H
 MOVWF DAT
 MOVLW 10H
 MOVWF YUE
 MOVLW 03H
 MOVWF ZHOU
 MOVLW 04H
 MOVWF YEAR
 RETURN
;
   
;結(jié)束
;讀時鐘數(shù)據(jù)
READTIME          
    BANKSEL TRISE
    CLRF TRISE
    BANKSEL PORTE   
 MOVLW 0BFH
 MOVWF TRBUF
 BSF  PORTE,RST
 CALL CMD  
 CALL RD0
 NOP 
  GOTO $

RD3    ;判斷是否起振
 BCF  STATUS,RP1
 BSF  STATUS,RP0
 BSF  TRISE,1
 NOP
 BCF  STATUS,RP1
 BCF  STATUS,RP0
 MOVLW 08H
 MOVWF LP2
  CALL RD1
 MOVF BUFF,W
 MOVWF FLAG
 BCF  PORTE,CLK
 BCF  PORTE,RST
 RETLW 00H 
;讀出7位時間數(shù)據(jù)
RD0
 
 BCF STATUS,RP1
 BSF STATUS,RP0
 BSF TRISE,1
 NOP
 BCF STATUS,RP1
 BCF STATUS,RP0
 MOVLW SS 
 MOVWF FSR
 CLRF BUFF
 MOVLW 07H
 MOVWF LP1
RD2
 MOVLW 08H
 MOVWF LP2
 CALL RD1
 MOVF BUFF,W
 MOVWF INDF
 INCF FSR,1
 DECFSZ LP1,F
 GOTO RD2
 BCF  PORTE,CLK
 BCF  PORTE,RST
 RETLW 00H
RD1
 BCF  PORTE,CLK
 BCF  STATUS,C
 BTFSC PORTE,IO
 BSF  STATUS,C
 RRF  BUFF,F
 BSF  PORTE,CLK
 DECFSZ LP2,F
 GOTO RD1
 RETURN
;連續(xù)寫入7位時間數(shù)據(jù)
WRTDS
 CALL   DS1302INITAL
 BCF STATUS,RP1
 BSF STATUS,RP0
 MOVLW 00H
 MOVWF TRISE
 BCF  STATUS,RP0
 BCF  STATUS,RP1
 MOVLW 0BEH
 MOVWF TRBUF
 BSF  PORTE,RST
 CALL CMD
 BCF  PORTE,CLK
 BCF  PORTE,IO
  MOVLW SS 
 MOVWF FSR
 MOVLW 08H
 MOVWF LP1
WRT1
 MOVF INDF,W
 MOVWF TRBUF
  CALL CMD
 INCF FSR,1
 DECFSZ LP1,1
 GOTO WRT1
 BCF     PORTE,CLK
 BCF     PORTE,RST 
 RETURN
;寫入8位數(shù)據(jù)
CMD
 BCF PORTE,CLK
 BCF PORTE,IO
 MOVLW 08H
 MOVWF LP2
CMD1
 BCF PORTE,CLK
 BTFSC TRBUF,0
 BSF PORTE,IO
 BTFSS TRBUF,0
 BCF PORTE,IO
 RRF TRBUF,1
 BSF PORTE,CLK
 DECFSZ LP2,1
 GOTO CMD1 
 RETLW 00H
;延時
DELAY
 MOVLW 0FFH
 MOVWF M
LOOP9
 MOVLW 0FFH
 MOVWF N 
 DECFSZ N,F
 GOTO $-1
 DECFSZ M,F
 GOTO LOOP9
 RETURN 
 END