'''
 PROJECT TWO
 
 This example demonstrates how to configure MULTIPLE GPIO pins as outputs to
 which LEDS are connected.
 
 A light chasing sequence is observed on 3 LEDS

   

Connection requirements

Connect EACH LED through a resistor, 2K2 down to the GND pin. 
Starting from the leftmost LED

LED1 --> GPIO21
LED2 --> GPIO19
LED3 --> GPIO18
LED4 --> GPIO5

Reference material

https://docs.micropython.org/en/latest/esp32/quickref.html#pins-and-gpio

NOTE THAT THE CODE BELOW IS NOT EFFICIENTLY WRITTEN. HOW CAN THIS BE CODED MORE
EFFICIENTLY.

'''
from machine import Pin, Timer       # Contains specific functions related to the                             # hardware on a particular board
from time import sleep         # module that contains time related functions

led_21 = Pin(21, Pin.OUT)      # create output pin on GPIO21
led_19 = Pin(19, Pin.OUT)      # create output pin on GPIO19
led_18 = Pin(18, Pin.OUT)      # create output pin on GPIO18
led_5 = Pin(5, Pin.OUT)
# Define functions used

i = 0
def binarycount(x):
    binary='{0:04b}'.format(x)
    led_21.value(int(binary[0]))
    led_19.value(int(binary[1]))
    led_18.value(int(binary[2]))
    led_5.value(int(binary[3]))

def handler_0(tim0):
  global i
  count = [0, 1, 2, 3]
  binarycount(2**count[i])
  i=i+1
  if i==4:
    i=0
  
tim0 = Timer(0)
tim0.init(period=1000 , mode=Timer.PERIODIC, callback=handler_0)