from machine import Pin, PWM
import time

# 핀 설정
led_pin = Pin(4, Pin.OUT)
button1 = Pin(13, Pin.IN, Pin.PULL_DOWN)

# PWM 인스턴스 생성
pwm = PWM(led_pin)
pwm.freq(1000)  # 1kHz 설정

while True:
    if button1.value() == 1:
        print("버튼 눌림 → LED 점멸 시작")
        start_time = time.ticks_ms()
        while time.ticks_diff(time.ticks_ms(), start_time) < 3000:  # 3초 동안 반복
            for dc in range(0, 65536, 4096):  # 밝기 증가
                pwm.duty_u16(dc)
                time.sleep(0.1)
            for dc in range(65535, -1, -4096):  # 밝기 감소
                pwm.duty_u16(dc)
                time.sleep(0.1)
        pwm.duty_u16(0)  # 종료 후 꺼짐
        print("LED 종료")
    
    time.sleep(0.05)  # 버튼 체크 간 딜레이