# 4 leds Serial_Blinking with time delay of 600ms
from machine import Pin
from time import sleep_ms
led1 = Pin(18,Pin.OUT)
led2 = Pin(19,Pin.OUT)
led3 = Pin(20,Pin.OUT)
led4 = Pin(21,Pin.OUT)
while True:
led1.value(not led1.value())
sleep_ms(600)
led1.value(not led1.value())
sleep_ms(600)
led2.value(not led2.value())
sleep_ms(600)
led2.value(not led2.value())
sleep_ms(600)
led3.value(not led3.value())
sleep_ms(600)
led3.value(not led3.value())
sleep_ms(600)
led4.value(not led4.value())
sleep_ms(600)
led4.value(not led4.value())
sleep_ms(600)