111 lines
2.4 KiB
Python
111 lines
2.4 KiB
Python
"""BLE link using BlueGiga adapter via PyGatt/BGAPI"""
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import pygatt
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from .base import BaseLink, LinkTimeoutException, LinkOpenException
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from binascii import hexlify
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SCAN_TIMEOUT = 3
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try:
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import queue
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except ImportError:
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import queue as queue
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class Fifo():
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def __init__(self):
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self.q = queue.Queue()
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def write(self, data): # put bytes
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for b in data:
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self.q.put(b)
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def read(self, size=1, timeout=None): # but read string
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res = ''
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for i in range(size):
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res += chr(self.q.get(True, timeout))
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return res
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#_cccd_uuid = '00002902-0000-1000-8000-00805f9b34fb'
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_rx_char_uuid = '6e400002-b5a3-f393-e0a9-e50e24dcca9e'
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_tx_char_uuid = '6e400003-b5a3-f393-e0a9-e50e24dcca9e'
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_write_chunk_size = 20 # as in android dumps
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class BLELink(BaseLink):
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def __init__(self, *args, **kwargs):
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super(BLELink, self).__init__(*args, **kwargs)
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self._adapter = None
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self._dev = None
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self._wr_handle = None
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self._rx_fifo = Fifo()
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def __enter__(self):
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self._adapter = pygatt.BGAPIBackend()
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self._adapter.start()
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return self
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def __exit__(self, exc_type, exc_value, traceback):
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self.close()
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def _make_rx_cb(self): # this is a closure :)
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def rx_cb(handle, value):
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self._rx_fifo.write(value)
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return rx_cb
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def scan(self):
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res = []
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devices = self._adapter.scan(timeout=SCAN_TIMEOUT)
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for dev in devices:
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if dev['name'].startswith(('MISc', 'NBSc')):
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res.append((dev['name'], dev['address']))
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return res
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def open(self, port):
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try:
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self._dev = self._adapter.connect(port, address_type=pygatt.BLEAddressType.random)
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self._dev.subscribe(_tx_char_uuid, callback=self._make_rx_cb())
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self._wr_handle = self._dev.get_handle(_rx_char_uuid)
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except pygatt.exceptions.NotConnectedError:
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raise LinkOpenException
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def close(self):
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if self._dev:
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self._dev.disconnect()
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self._dev = None
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if self._adapter:
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self._adapter.stop()
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def read(self, size):
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try:
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data = self._rx_fifo.read(size, timeout=self.timeout)
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except queue.Empty:
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raise LinkTimeoutException
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if self.dump:
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print('<', hexlify(data).upper())
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return data
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def write(self, data):
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if self.dump:
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print('>', hexlify(data).upper())
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size = len(data)
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ofs = 0
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while size:
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chunk_sz = min(size, _write_chunk_size)
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self._dev.char_write_handle(self._wr_handle, bytearray(data[ofs:ofs+chunk_sz]))
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ofs += chunk_sz
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size -= chunk_sz
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__all__ = ['BLELink']
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