005 - ESP32 MicroPython: Pulse Width Modulation

# DC motor speed control using PWM in MicroPython
# Author: George Bantique, TechToTinker
# Date: September 13, 2020

# Load the machine module which also
# includes the pwm class
import machine

# Create the drives object for the direction
# of rotation of the DC motor
dr1 = machine.Pin(21, machine.Pin.OUT)
dr2 = machine.Pin(19, machine.Pin.OUT)

# Create the en1 object as normal GPIO
en1 = machine.Pin(18, machine.Pin.OUT)

# Create a pwm object and attach it to
# pwm drivers
pwm = machine.PWM(en1)

# Rotates the DC motor clockwise
def cw():
    dr1.value(1)
    dr2.value(0)
    
# Rotates the DC motor counter-clockwise    
def ccw():
    dr1.value(0)
    dr2.value(1)

# Starts the pwm with a definite value
# and start the motor rotating according 
# to the input argument
def start(rotation):
    pwm.init(freq=1, duty=512)
    if (rotation=='cw'):
        cw()
    elif (rotation=='ccw'):
        ccw()

# Stops the pwm using pwm.deinit() function
# which dettach the pwm driver to the en1 object
# We also provide the drives pin a logic low value
def stop():
    pwm.deinit()
    dr1.value(0)
    dr2.value(0)