def receive(self):
seq = 0
len_ = 0
payload = bytearray()
crc = 0
rx_crc = 0
hdr_len = struct.calcsize(PBStx.DHEADER)
crc_len = struct.calcsize(PBStx.CRCFMT)
while not self.terminate.is_set():
# 1. wait start marker
c = self.ser.read(1)
if len(c) == 0 or ord(c[0]) != PBStx.STX:
continue
# 2. read header
buf = self._read_or_die(hdr_len)
rx_crc = xmodem_crc16(buf)
seq, len_ = struct.unpack(PBStx.DHEADER, buf)
# 3. read payload
payload = self._read_or_die(len_)
rx_crc = xmodem_crc16(payload, rx_crc)
# 4. read crc
buf = self._read_or_die(crc_len)
crc, = struct.unpack(PBStx.CRCFMT, buf)
# 5. check crc
if crc == rx_crc:
return self._deserialize(seq, payload)
else:
raise ReceiveError("CRC mismatch: 0x{:04x} != 0x{:04x}".format(crc, rx_crc))
def receive(self):
seq = 0
len_ = 0
payload = bytearray()
crc = 0
rx_crc = 0
hdr_len = struct.calcsize(PBStx.DHEADER)
crc_len = struct.calcsize(PBStx.CRCFMT)
while not self.terminate.is_set():
# 1. wait start marker
c = self.ser.read(1)
if len(c) == 0 or ord(c[0]) != PBStx.STX:
continue
# 2. read header
buf = self._read_or_die(hdr_len)
rx_crc = xmodem_crc16(buf)
seq, len_ = struct.unpack(PBStx.DHEADER, buf)
# 3. read payload
payload = self._read_or_die(len_)
rx_crc = xmodem_crc16(payload, rx_crc)
# 4. read crc
buf = self._read_or_die(crc_len)
crc, = struct.unpack(PBStx.CRCFMT, buf)
# 5. check crc
if crc == rx_crc:
return self._deserialize(seq, payload)
else:
raise ReceiveError("CRC mismatch: 0x{:04x} != 0x{:04x}".format(
crc, rx_crc))
def send(self, pbobj):
if not isinstance(pbobj, msgs.Message):
raise ValueError("Unknown object: " + repr(pbobj))
payload = pbobj.SerializeToString()
if len(payload) > PBStx.MAX_LEN:
raise ValueError("Serialized {} too long: {}".format(repr(pbobj), len(payload)))
buf = struct.pack(PBStx.EHEADER, PBStx.STX, self._tx_seq, len(payload))
buf += payload
tx_crc = xmodem_crc16(buf[1:])
buf += struct.pack(PBStx.CRCFMT, tx_crc)
self._tx_seq += 1
self.ser.write(buf)
def send(self, pbobj):
if not isinstance(pbobj, msgs.Message):
raise ValueError("Unknown object: " + repr(pbobj))
payload = pbobj.SerializeToString()
if len(payload) > PBStx.MAX_LEN:
raise ValueError("Serialized {} too long: {}".format(repr(pbobj), len(payload)))
buf = struct.pack(PBStx.EHEADER, PBStx.STX, self._tx_seq, len(payload))
buf += payload
tx_crc = xmodem_crc16(buf[1:])
buf += struct.pack(PBStx.CRCFMT, tx_crc)
self._tx_seq += 1
self.ser.write(buf)
