Grounding GP0 on boot removes CDC and MSC devices

Author: emanuelen5

pico/boot.py

@@ -0,0 +1,19 @@
+"""
+boot.py file for Pico data logging example. If pin GP0 is connected to GND when
+the pico starts up, make the filesystem writeable by CircuitPython.
+"""
+import board
+import digitalio
+import storage
+from buttons import btns, pins
+
+print(f"Checking if btn[0]={pins[0]} is pressed.")
+
+# If write pin is connected to ground on start-up, CircuitPython can write to CIRCUITPY filesystem.
+if not btns[0].value:
+    print("Mounting as read-only for host! Disabling storage and serial port.")
+    storage.remount("/", readonly=False)
+    storage.disable_usb_drive()
+    usb_cdc.disable()
+else:
+    print("Not pressed. Starting in RW mode.")