light.asm

C51 编写的通过按键调节led灯亮度的程序,用定时器产生可调PWM.

LIST P=18F452
INCLUDE "P18F452.INC"
		ORG 0000H
		GOTO MAIN
		ORG 0020H
MAIN 	BSF STATUS,5
	 	CLRF TRISD
	 	BCF STATUS,5
	 	MOVLW B'11111111'
	 	MOVWF PORTD
LOOP 	CALL DELAY1S
		DECFSZ PORTD,1
	 	GOTO LOOP
	 	GOTO ABC
DELAY1S MOVLW 06H
	    MOVWF 20H
LOOP1	MOVLW 0EBH
		MOVWF 21H
LOOP2	MOVLW 0ECH
		MOVWF 22H
LOOP3	DECFSZ 22H
		GOTO LOOP3
		DECFSZ 21H
		GOTO LOOP2
		DECFSZ 20H
		GOTO LOOP1
		RETURN
ABC     NOP
		END