#INCLUDE "p16f84a.inc" 					
	LIST p=16f84a
	ERRORLEVEL -302    				
	__CONFIG _XT_OSC &_PWRTE_ON & _WDT_OFF &_CP_OFF	
						
	CBLOCK		0x0C					
		W_TEMP
		S_TEMP
		MTIM
		KIM
	ENDC

	ORG 0X000
		GOTO	START	
	ORG	0X004
		BCF		INTCON,T0IF
PUSH	MOVWF	W_TEMP
		SWAPF	STATUS,W
		MOVWF	S_TEMP
		MOVLW	H'EE'
		MOVWF	MTIM	
NYIT	BTFSS	PORTA,2
		GOTO	NOMNYIT
		MOVLW	H'EE'
		MOVWF	MTIM
		GOTO	POP
NOMNYIT	NOP
		NOP
		NOP
		DECFSZ	MTIM,F	
		GOTO	NYIT
		CALL	NYITÁS
		GOTO	POP			
POP		SWAPF	S_TEMP,W
		MOVF	STATUS
		SWAPF	W_TEMP,F
		SWAPF	W_TEMP,W
	RETFIE

START	BSF		STATUS,RP0
		MOVLW	B'00001111'
		MOVWF	TRISB		
		MOVLW	B'00011100'
		MOVWF	TRISA		
		MOVLW	B'10000111'
		MOVWF	OPTION_REG
		BCF		STATUS,RP0	
		BSF		INTCON,GIE
		BSF		INTCON,T0IE	
		CLRF	PORTA
		CLRF	PORTB
		MOVLW	H'00'
		MOVWF	KIM	
			
STAR	BTFSS	KIM,0	
		GOTO	KI
		BSF		PORTA,1
		GOTO	STAR

KI		BCF		PORTA,1
		GOTO	STAR
		
NYITÁS:	MOVFW	KIM
		XORLW	B'11111111'
		ANDLW	B'00000001'
		MOVWF	KIM			
		RETURN
 
	END