code.py

import bleio
import board
import digitalio
import time
import binascii
import microcontroller

# User service UUID: Change this to your generated service UUID
USER_SERVICE_UUID = "91E4E176-D0B9-464D-9FE4-52EE3E9F1552"
# User service characteristics
WRITE_CHARACTERISTIC_UUID ="E9062E71-9E62-4BC6-B0D3-35CDCD9B027B"
NOTIFY_CHARACTERISTIC_UUID = "62FBD229-6EDD-4D1A-B554-5C4E1BB29169"

# PSDI Service UUID: Fixed value for Developer Trial
PSDI_SERVICE_UUID = "E625601E-9E55-4597-A598-76018A0D293D"
PSDI_CHARACTERISTIC_UUID = "26E2B12B-85F0-4F3F-9FDD-91D114270E6E"

def ble_uuid(str_uuid):
    return bleio.UUID(binascii.unhexlify(WRITE_CHARACTERISTIC_UUID.replace("-", "")))

pin_led = digitalio.DigitalInOut(board.RED_LED)
pin_led.switch_to_output(False)
pin_sw = digitalio.DigitalInOut(board.SWITCH)
pin_sw.switch_to_input(digitalio.Pull.UP)

# Create characteristic and service.
write_characteristic = bleio.Characteristic(ble_uuid(WRITE_CHARACTERISTIC_UUID), write=True)
notify_characteristic = bleio.Characteristic(ble_uuid(NOTIFY_CHARACTERISTIC_UUID), notify=True)
user_service = bleio.Service(ble_uuid(USER_SERVICE_UUID), [write_characteristic, notify_characteristic])

psdi_characteristic = bleio.Characteristic(ble_uuid(PSDI_CHARACTERISTIC_UUID), read=True)
psdi_service = bleio.Service(ble_uuid(PSDI_SERVICE_UUID), [psdi_characteristic], secondary=True)

# Create a peripheral and start it up.
periph = bleio.Peripheral([user_service, psdi_service])
periph.start_advertising()

psdi_characteristic.value = microcontroller.cpu.uid

while not periph.connected:
    # Wait for connection.
    pass

while periph.connected:
    pin_led.value = bool(write_characteristic.value[0])
    
    sw_value = not pin_sw.value
    if bool(notify_characteristic.value[0]) != sw_value:
        print(sw_value)
        notify_characteristic.value = bytes([1 if sw_value else 0])

    time.sleep(0.1)