ORG 	$1000 
R_edge_1	  DS.W 1
	LDAA 	#$FF		
	STAA	DDRA			
	STAA	DDRB			
	LDAA 	#$80		
	STAA	TSCR1			
	LDAA 	#$0		
	STAA	TSCR2			
	BCLR	TIOS,%01000000	
	LDAA 	#%00010000			
	STAA	TCTL3		
	BSET	TFLG1,%01000000	
HERE1	BRCLR	TFLG1,mTFLG1_C6F,HERE1	
	LDD	TC6	
	STD	R_edge_1 
	BSET	TFLG1,%01000000	
HERE2	BRCLR	TFLG1,mTFLG1_C6F,HERE2	
	LDD	TC6	
	SUBD	R_edge_1	
	STAA	PORTA
	STAB	PORTB	
	BRA $