def _receive_packet(self, quiet=False):
if self.software_only:
return True
header = 0
while True:
ch = self.ser.read(1)
if len(ch) < 1:
if not quiet:
log.error("receive packet: response timeout")
return (PACKET_ACK_TIMEOUT, "")
if (ord(ch) == 0xFF):
header += 1
else:
header = 0
if header == 2:
break
ack = PACKET_ACK_OK
raw_packet = self.ser.read(RAW_PACKET_SIZE)
if len(raw_packet) != RAW_PACKET_SIZE:
if not quiet:
log.error("receive packet: timeout")
ack = PACKET_ACK_TIMEOUT
if ack == PACKET_ACK_OK:
packet = pack7.unpack_7bit(raw_packet)
if len(packet) != PACKET_SIZE:
ack = PACKET_ACK_INVALID
if not quiet:
log.error("receive_packet: Unpacked length incorrect")
if ack == PACKET_ACK_OK:
received_crc = unpack("<H", packet[6:8])[0]
packet = packet[0:6]
crc = 0
for ch in packet:
crc = crc16_update(crc, ord(ch))
if received_crc != crc:
if not quiet:
log.error("receive_packet: CRC fail")
ack = PACKET_ACK_CRC_FAIL
# Send the response back to the dispenser
if self.ser.write(chr(ack)) != 1:
if not quiet:
log.error("receive_packet: Send ack timeout!")
ack = PACKET_ACK_TIMEOUT
if ack == PACKET_ACK_OK:
return (ack, packet)
else:
return (ack, "")
def _receive_packet(self, quiet=False):
if self.software_only:
return True
header = 0
while True:
ch = self.ser.read(1)
if len(ch) < 1:
if not quiet:
log.error("receive packet: response timeout")
return (PACKET_ACK_TIMEOUT, "")
if (ord(ch) == 0xFF):
header += 1
else:
header = 0
if header == 2:
break
ack = PACKET_ACK_OK
raw_packet = self.ser.read(RAW_PACKET_SIZE)
if len(raw_packet) != RAW_PACKET_SIZE:
if not quiet:
log.error("receive packet: timeout")
ack = PACKET_ACK_TIMEOUT
if ack == PACKET_ACK_OK:
packet = pack7.unpack_7bit(raw_packet)
if len(packet) != PACKET_SIZE:
ack = PACKET_ACK_INVALID
if not quiet:
log.error("receive_packet: Unpacked length incorrect")
if ack == PACKET_ACK_OK:
received_crc = unpack("<H", packet[6:8])[0]
packet = packet[0:6]
crc = 0
for ch in packet:
crc = crc16_update(crc, ord(ch))
if received_crc != crc:
if not quiet:
log.error("receive_packet: CRC fail")
ack = PACKET_ACK_CRC_FAIL
# Send the response back to the dispenser
if self.ser.write(chr(ack)) != 1:
if not quiet:
log.error("receive_packet: Send ack timeout!")
ack = PACKET_ACK_TIMEOUT
if ack == PACKET_ACK_OK:
return (ack, packet)
else:
return (ack, "")