MatrixPortal M4 up/down switch to toggle filesystem read-only/write modes

boot.py

# This script allows the MatrixPortal M4 to switch between:
# 1. readonly mode: write to drive when connected to computer over USB C (Down button)
# 2. write mode: CircuitPython can write to itself (Up button)
# Useful when developing code to pair Wifi networks.
# Think of "down" button as developer mode (code cannot write to file system)
# and "up" button as production: (code can write to file system)
#
# After hitting "reset" button twice, or reconnecting USB-C cable:
# neopixel will flash orange three times, then teal when accepting up/down button press
# blue indicates readonly mode
# green indicates write mode
import board
import busio
from digitalio import DigitalInOut, Pull
import displayio
import neopixel
import storage
import terminalio
import time

from adafruit_debouncer import Debouncer


LISTEN_TIMEOUT_SECONDS = 5

def listen_for_up_down_button_press():
    pin_down = DigitalInOut(board.BUTTON_DOWN)
    pin_down.switch_to_input(pull=Pull.UP)
    button_down = Debouncer(pin_down)
    pin_up = DigitalInOut(board.BUTTON_UP)
    pin_up.switch_to_input(pull=Pull.UP)
    button_up = Debouncer(pin_up)

    status_light = neopixel.NeoPixel(
        board.NEOPIXEL, 1, brightness=0.1
    )

    start_time = time.time()

    status_light.fill((0, 150, 150))
    status_light.show()

    # down to toggle dev mode (readonly true)
    # up to toggle circuitpython write access
    while True:
        button_down.update()
        button_up.update()

        if button_up.fell:
            status_light.fill((0, 200, 0))
            status_light.show()
            print('remounting to readonly false')
            storage.remount('/', readonly=False)
            time.sleep(1)
            status_light.fill((0, 0, 0))
            break
        elif button_down.fell:
            print('remounting to readonly true')
            status_light.fill((0, 0, 200))
            status_light.show()
            storage.remount('/', readonly=True)
            time.sleep(1)
            status_light.fill((0, 0, 0))
            break
        elif time.time() - start_time > LISTEN_TIMEOUT_SECONDS:
            print('no up/down presses detected')
            status_light.fill((0, 0, 0))
            break


listen_for_up_down_button_press()