1  """
 2  Used with ble_uart_echo_client.py. Receives characters from the UARTService and transmits them back.
 3  """
 4  
 5  from adafruit_ble import BLERadio
 6  from adafruit_ble.advertising.standard import ProvideServicesAdvertisement
 7  from adafruit_ble.services.nordic import UARTService
 8  
 9  ble = BLERadio()
10  uart = UARTService()
11  advertisement = ProvideServicesAdvertisement(uart)
12  
13  while True:
14      ble.start_advertising(advertisement)
15      while not ble.connected:
16          pass
17      while ble.connected:
18          # Returns b'' if nothing was read.
19          one_byte = uart.read(1)
20          if one_byte:
21              print(one_byte)
22              uart.write(one_byte)