CircuitPython Ultrasonic Robot Main Code

# Write your code here :-)
import board
import pulseio
from digitalio import DigitalInOut, Direction
import adafruit_hcsr04
import time

sonar = adafruit_hcsr04.HCSR04(trigger_pin=board.D12, echo_pin=board.D11)

EN1_PIN = board.D6
EN2_PIN = board.D5
IN1_PIN = board.D7
IN2_PIN = board.D4
en1 = None
en2 = None
in1 = None
in2 = None
uart = None

def motor_1(pwm, reverse=False):
    global en1
    en1.duty_cycle = pwm * 255
    if reverse:
        in1.value = True
    else:
        in1.value = False

def motor_2(pwm, reverse=False):
    global en1
    en2.duty_cycle = pwm * 255
    if reverse:
        in2.value = True
    else:
        in2.value = False


def setup():
    global en1
    global en2
    global in1
    global in2
    en1 = pulseio.PWMOut(EN1_PIN, frequency=5000, duty_cycle=0)
    en2 = pulseio.PWMOut(EN2_PIN, frequency=500, duty_cycle=0)
    in1 = DigitalInOut(IN1_PIN)
    in1.direction = Direction.OUTPUT
    in2 = DigitalInOut(IN2_PIN)
    in2.direction = Direction.OUTPUT

setup()


while True:
    motor_1(255)
    motor_2(255)

    distance = 0

    try:
       distance = sonar.distance
    except RuntimeError:
        print("Retrying!")

    print((distance,))

    if distance > 0 and distance < 8:
        motor_1(0)
        motor_2(0)

        time.sleep(0.2)

        motor_1(255, reverse=True)
        motor_2(255, reverse=True)

        time.sleep(0.8)

        motor_1(255, reverse=False)
        motor_2(255, reverse=True)

        time.sleep(0.5)