from machine import Pin, I2C
import time
import pcf8575

SCL = 17
SDA = 16

# I2C 設定 (依你的板子腳位調整)
i2c = I2C(0, scl=Pin(SCL), sda=Pin(SDA), freq=400000)

pcf = pcf8575.PCF8575(i2c, 0x20)

while True:
  # turn LED on
  pcf.port = 0x0000
  time.sleep_ms(500)
  
  # turn LED off
  pcf.port = 0xFFFF
  time.sleep_ms(500)

  leds = 1
  for i in range(16):
    # 將要控制的燈狀態寫入 PCF8575
    pcf.port = 0x0000
    time.sleep_ms(100)
    pcf.port = leds
    time.sleep_ms(100)

    # 計算要打開的燈的位置
    leds = leds << 1