1  # The MIT License (MIT)
  2  #
  3  # Copyright (c) 2019 Dan Halbert for Adafruit Industries
  4  # Copyright (c) 2019 Scott Shawcroft for Adafruit Industries
  5  #
  6  # Permission is hereby granted, free of charge, to any person obtaining a copy
  7  # of this software and associated documentation files (the "Software"), to deal
  8  # in the Software without restriction, including without limitation the rights
  9  # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 10  # copies of the Software, and to permit persons to whom the Software is
 11  # furnished to do so, subject to the following conditions:
 12  #
 13  # The above copyright notice and this permission notice shall be included in
 14  # all copies or substantial portions of the Software.
 15  #
 16  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 17  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 18  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 19  # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 20  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 21  # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 22  # THE SOFTWARE.
 23  """
 24  `adafruit_ble_berrymed_pulse_oximeter.adafruit_ble_transparent_uart`
 25  =============================================================================
 26  
 27  This module provides Services used by MicroChip
 28  
 29  """
 30  
 31  from adafruit_ble import Service
 32  from adafruit_ble.uuid import VendorUUID
 33  from adafruit_ble.characteristics.stream import StreamOut, StreamIn
 34  
 35  __version__ = "0.0.0-auto.0"
 36  __repo__ = (
 37      "https://github.com/adafruit/Adafruit_CircuitPython_BLE_Contec_Pulse_Oximeter.git"
 38  )
 39  
 40  
 41  class TransparentUARTService(Service):
 42      """
 43      Provide UART-like functionality via MicroChip
 44  
 45      :param int timeout:  the timeout in seconds to wait
 46        for the first character and between subsequent characters.
 47      :param int buffer_size: buffer up to this many bytes.
 48        If more bytes are received, older bytes will be discarded.
 49      """
 50  
 51      # pylint: disable=no-member
 52      uuid = VendorUUID("49535343-FE7D-4AE5-8FA9-9FAFD205E455")
 53      _server_tx = StreamOut(
 54          uuid=VendorUUID("49535343-1E4D-4BD9-BA61-23C647249616"),
 55          timeout=1.0,
 56          buffer_size=64,
 57      )
 58      _server_rx = StreamIn(
 59          uuid=VendorUUID("49535343-8841-43F4-A8D4-ECBE34729BB3"),
 60          timeout=1.0,
 61          buffer_size=64,
 62      )
 63  
 64      def __init__(self, service=None):
 65          super().__init__(service=service)
 66          self.connectable = True
 67          if not service:
 68              self._rx = self._server_rx
 69              self._tx = self._server_tx
 70          else:
 71              # If we're a client then swap the characteristics we use.
 72              self._tx = self._server_rx
 73              self._rx = self._server_tx
 74  
 75      def read(self, nbytes=None):
 76          """
 77          Read characters. If ``nbytes`` is specified then read at most that many bytes.
 78          Otherwise, read everything that arrives until the connection times out.
 79          Providing the number of bytes expected is highly recommended because it will be faster.
 80  
 81          :return: Data read
 82          :rtype: bytes or None
 83          """
 84          return self._rx.read(nbytes)
 85  
 86      def readinto(self, buf, nbytes=None):
 87          """
 88          Read bytes into the ``buf``. If ``nbytes`` is specified then read at most
 89          that many bytes. Otherwise, read at most ``len(buf)`` bytes.
 90  
 91          :return: number of bytes read and stored into ``buf``
 92          :rtype: int or None (on a non-blocking error)
 93          """
 94          return self._rx.readinto(buf, nbytes)
 95  
 96      def readline(self):
 97          """
 98          Read a line, ending in a newline character.
 99  
100          :return: the line read
101          :rtype: bytes or None
102          """
103          return self._rx.readline()
104  
105      @property
106      def in_waiting(self):
107          """The number of bytes in the input buffer, available to be read."""
108          return self._rx.in_waiting
109  
110      def reset_input_buffer(self):
111          """Discard any unread characters in the input buffer."""
112          self._rx.reset_input_buffer()
113  
114      def write(self, buf):
115          """Write a buffer of bytes."""
116          self._tx.write(buf)