R1 EQU $1201			
R2 EQU $1202
R3 EQU $1203
COUNT_1 EQU 100	
COUNT_2 EQU 100
COUNT_3 EQU 10
	LDAA	#$FF
	STAA	DDRB		
	LDAA	#$55
	STAA	PORTB
	LDAA	#COUNT_3
	STAA	R3
LOP_3	LDAA	#COUNT_2
	STAA	R2
LOP_2	LDAA	#COUNT_1
	STAA	R1
LOP_1	COM	PORTB
	DEC	R1
	BNE	LOP_1
	DEC	R2
	BNE	LOP_2
	DEC	R3
	BNE	LOP_3