ORG 0H

COUNT EQU 30H 
PASS EQU 20H 

; MAIN PROGRAM 

	MOV	TMOD,#01H ;SET TIMER0 MODE TO 1	
	MOV	COUNT,#00H ;SET COUNT TO 00 
	MOV	A,COUNT	 ;MOVE COUNT TO ACCUMULATOR 
	MOV	P1,A	 ;OUTPUT 00 

DC0:	
	MOV	PASS,#05H ;SETS TIME DELAY TO 1 SEC.DELAY 
	MOV	TL0,#0ECH ;SET LOW BYTE TO 68 DECIMAL 
	MOV	TH0,#16H ;SET HIGH BYTE TO 58 DECIMAL 

DC1:	
	SETB	TR0	 ;START TIMER 

DD1:	
	JNB	TF0,DD1	 ;WAIT FOR OVERFLOW 
	CLR	TF0	 ;CLEAR FLAG 
	CLR	TR0	 ;STOP TIMER 
	DJNZ	PASS,DC1	;LOOP 5 TIMES 

BEG:	
	MOV	A,COUNT	 ;MOVE COUNT TO ACCUMULATOR 
	ADD	A,#01H	 ;ADD 1 TO ACCUMULATOR 
	DA	A	 ;DECIMAL ADJUST A 
	MOV	COUNT,A	 ;MOVE ACCUM NUMBER BACK TO COUNT 

SWTCH:	
	SETB	P3.0	 ;CHECK P3.0 SWITCH 
	JNB	P3.0,SWTCH 
	MOV	P1,COUNT	;OUTPUT NUMBER TO LEDS 
	SJMP	DC0	 ;JUMP BACK TO LOOP 

/* CountDown
BEG: MOV A,COUNT1     ; Move LSD to A
    DEC  A            ; Decrement the LSD
    CJNE 0FFh, BEG2   ; Check for underflow
    MOV  COUNT1, #09h ; If underflow, reload with 09 and dec MSD
;
    MOV  A, COUNT2    ; Fetch MSD
    DEC  A            ; Decrement the MSD
    CJNE 0FFh, BEG1   ; Check for underflow
    MOV  A, #09h      ; Reload MSD with 9
BEG1: MOV COUNT2, A   ; Save the MSD
    JP   BEG3         ; Jump to end
BEG2: MOV COUNT1,A    ; Save LSD
BEG3:
*/

END