12887.asm

12887时钟计数器,提供标准的时钟,定时,显示时间

	
		    ORG   0000H
		    AJMP  MAIN
		    ORG   0003H
		    AJMP  ITOP
		    ORG   0030H
	   MAIN:    CLR   EA
		    CLR   A	
		    MOV   PSW,A
		    MOV   IE,A      
		    MOV	  SP,#60H
	 	    MOV   TCON,#00H
                MOV     R0,#7FH
INIT1:		MOV	@R0,A  ;INIT1的功能是将内部数据存储器（RAM），即7FH到00H的内容清零
		DEC	R0     ;R0里面内容减一
		CJNE	R0,#00H,INIT1 

;===========================================
   INIT8279:	CLR     A
                MOV	DPTR,#7001H     ;8279初始化
		MOVX	@DPTR,A
       	        MOV	DPTR,#7001H 
		MOV	A,#32H
		MOVX	@DPTR,A       
		MOV	DPTR,#7001H
		MOV	A,#90H
		MOVX	@DPTR,A
;============================================
INT12887:         MOV DPTR,#500BH           ;12887初始化
		  MOV A,#10100010B
	
		  MOVX @DPTR,A
		  MOV DPTR,#5000H        ;初始化秒
	 	  MOV A,#00H     
		  MOVX @DPTR,A
	
		  INC DPTR               ;初始化秒闹
		  MOV A,#0FFH  
		  MOVX @DPTR,A

		  INC DPTR               ;初始化分 
		  MOV A,#59H	       
		  MOVX @DPTR,A

		  INC DPTR               ;初始化分闹
		  MOV A,#00H
		  MOVX @DPTR,A
		  
		  MOV DPTR,#500AH        ;初始化A寄存器
		  MOV A,#26H
		  MOVX @DPTR,A
		  MOV DPTR,#500CH        ;初始化B寄存器
		  MOVX A,@DPTR
		  MOV DPTR,#500DH        ;初始化D寄存器
		  MOVX A,@DPTR
	          MOV A,#80H
		  MOVX @DPTR,A
		  MOV DPTR,#500BH        ;设置B寄存器
		  MOV A,#1AH 
		  MOVX @DPTR,A
		
                  MOV     IE,#81H        ;中断初始化，外部更新中断0

                  JMP     $

                



;==================================
RDTIME: 	MOV	DPTR,#5000H      ;
		MOVX	A,@DPTR
		MOV	50H,A		;RD SECOND
		INC	DPTR
		INC	DPTR
		MOVX	A,@DPTR 	;RD MINUTES
		MOV	51H,A
		INC	DPTR
		INC	DPTR
		MOVX	A,@DPTR 	;RD HOUR
		MOV	52H,A 

  AAA:          MOV     R0,52H
                MOV     A,@R0
        	ANL     A,#0FH
		MOV     41H,A
		SWAP    A
		ANL     A,#0FH
		MOV     40H,A
		MOV     42H,#13H      

	        MOV     R0,51H
                MOV     A,@R0
        	ANL     A,#0FH
		MOV     44H,A
		SWAP    A
		ANL     A,#0FH
		MOV     43H,A
		MOV     45H,#13H

		MOV     R0,50H
                MOV     A,@R0
        	ANL     A,#0FH
		MOV     47H,A
		SWAP    A
		ANL     A,#0FH
		MOV     46H,A
 ;=====================================================
 DISPALL:	MOV	30H,#80H       ;30单元存放写显示RAM命令,非自动加一.
		MOV	31H,#40H       ;31单元存放读键盘RAM命令,非自动加一.
		MOV	R7,#06H
  DISP1:	MOV	DPTR,#7001H
		MOV	A,30H
		MOVX	@DPTR,A        ;指针指向80H
		MOV	R0,31H
		MOV	A,@R0
		MOV	DPTR,#DISPCODE
		MOVC	A,@A+DPTR
		MOV	DPTR,#7000H
		MOVX	@DPTR,A
		INC	31H
		INC	30H
		DJNZ	R7,DISP1
		RET
 ;========================================
DISPCODE:	DB	0CH,9FH,4AH,0BH,99H,29H,28H,8FH
		DB	08H,09H,88H,38H,6CH,1AH,68H,0E8H
		DB	0C8H,3AH,0ECH,0FFH
 ;=====================================================
    ITOP:       CLR     EA
                LCALL   RDTIME
                LCALL   DISPALL
                SETB    EA
    
                RETI
 
 ;=====================================================
		END