TCOUNT02MS  EQU  30H
TCOUNT2S    EQU  31H
ID          EQU  32H           
			ORG   0000H
			LJMP  START
			ORG   0BH
    		LJMP  INT0X

START:	    MOV TCOUNT02MS,#00H
			MOV TCOUNT2S,#00H
			MOV ID,#00H
            MOV TMOD,#01H
			
			MOV TH0,#(65535-50000)/256
			MOV TL0,#(65535-50000) MOD 256
			SETB TR0
			SETB ET0
			SETB EA
			SJMP $
INT0X:		MOV TH0,#(65535-50000)/256
			MOV TL0,#(65535-50000) MOD 256
			INC TCOUNT2S
			MOV A,TCOUNT2S
			CJNE A,#40,NEXT
			MOV TCOUNT2S,#00H
			INC ID
			MOV A,ID 
			CJNE A,#04H,NEXT
			MOV ID,#00H
			;INC TCOUNT02MS
			;MOV A,TCOUNT02MS
			;CJNE A,#04H,NEXT
			;MOV TCOUNT02MS,#00H
NEXT:       ;INC ID
            ;MOV A,ID
			;CJNE A,#04H,ID1
			;MOV ID,#00H
			INC TCOUNT02MS
			MOV A,TCOUNT02MS
			CJNE A,#04H,DONE
			MOV  TCOUNT02MS,#00H
ID1:        MOV A,ID
            CJNE A,#00H,ID2
			CPL  P1.0
			SETB P1.1
			SETB P1.2
			SETB P1.3
			SJMP DONE
ID2:        CJNE A,#01H,ID3
        	CPL  P1.1
			SETB P1.0
			SETB P1.2
			SETB P1.3
			SJMP DONE
ID3:        CJNE A,#02H,ID4
        	CPL  P1.2
			SETB P1.0
			SETB P1.1
			SETB P1.3
			SJMP DONE
ID4:        CJNE A,#03H,DONE
        	CPL  P1.3
			SETB P1.0
			SETB P1.2
			SETB P1.1
			SJMP DONE
DONE:       RETI
            END