BSET DDRB,%00000001		
		BCLR DDRA,%10000000		
		BCLR PORTB,%00000001	
CHK
		BRCLR PORTA,%10000000,PWM_50
		BCLR PORTB,%00000001	
		JSR DELAY
		BSET PORTB,%00000001	
		JSR DELAY
		JSR DELAY
		JSR DELAY
		BRA  CHK			
PWM_50
		BSET PORTB,%00000001		
		JSR DELAY
		JSR DELAY
		BCLR PORTB,%00000001		
		JSR DELAY
		JSR DELAY
		BRA CHK