def receive_command(self, len_of_response):
for i in range(len_of_response):
try:
c = bus.read_byte(DEVICE_ADDRESS)
except:
#print("error in " + str(i))
return self.BYTE_READ_FAILED
# print("Recieved byte: " + str(hex(c)))
msg = self.check_command(c)
if msg != None and msg != -1 and msg != self.CRC_CHECK_FAILED:
self.buffer_receive.clear()
return msg
elif msg == self.CRC_CHECK_FAILED:
raise crc_check_failed("CRC check failed!")
else:
return None
def check_command(self, received_byte):
global buffer_receive
global buffer_receive_index
datalen = 0
if buffer_receive_index == 0 and received_byte != START_BYTE_RECIEVED:
return -1
buffer_receive.append(received_byte)
buffer_receive_index += 1
if buffer_receive_index < PROTOCOL_HEADER_SIZE:
return -1
datalen = (buffer_receive[3] << 8) | buffer_receive[4]
if datalen > 32:
# print("="*50)
# print('[{}]'.format(', '.join(hex(x) for x in buffer_receive)))
buffer_receive_index = 0
buffer_receive.clear()
if buffer_receive_index == (PROTOCOL_FRAME_SIZE + datalen):
crc_received = (
buffer_receive[PROTOCOL_FRAME_SIZE + datalen - 2] << 8
) | buffer_receive[PROTOCOL_FRAME_SIZE + datalen - 1]
# print("CRC Received: " + str(crc_received))
crc_calculated = self.calculate_crc16(
buffer_receive[0 : PROTOCOL_HEADER_SIZE + datalen], 1
)
# print("CRC Calculated: " + str(crc_calculated))
if crc_calculated == crc_received:
# print("CRC Check OK")
# print('[{}]'.format(', '.join(hex(x) for x in buffer_receive)))
buffer_receive_index = 0
return buffer_receive[0 : PROTOCOL_FRAME_SIZE + datalen]
else:
print("CRC Check FAILED!")
buffer_receive_index = 0
raise crc_check_failed("CRC check failed!")
def check_command(self, received_byte):
datalen = 0
if self.buffer_receive_index == 0 and received_byte != START_BYTE_RECIEVED:
return -1
self.buffer_receive.append(received_byte)
self.buffer_receive_index += 1
if self.buffer_receive_index < PROTOCOL_HEADER_SIZE:
return -1
datalen = (self.buffer_receive[3] << 8) | self.buffer_receive[4]
if datalen > 32:
# print("="*50)
# print('[{}]'.format(', '.join(hex(x) for x in self.buffer_receive)))
self.buffer_receive_index = 0
self.buffer_receive.clear()
if self.buffer_receive_index == (PROTOCOL_FRAME_SIZE + datalen):
crc_received = (
self.buffer_receive[PROTOCOL_FRAME_SIZE + datalen - 2] <<
8) | self.buffer_receive[PROTOCOL_FRAME_SIZE + datalen - 1]
# print("CRC Received: " + str(crc_received))
crc_calculated = self.calculate_crc16(
self.buffer_receive[0:PROTOCOL_HEADER_SIZE + datalen], 1)
# print("CRC Calculated: " + str(crc_calculated))
#debugging invalid information received
try:
#print("CRC Check OK")
#print('[{}]'.format(', '.join(hex(x) for x in self.buffer_receive)))
self.buffer_receive_index = 0
return self.buffer_receive[0:PROTOCOL_FRAME_SIZE + datalen]
except Exception as e:
#print("CRC Check FAILED!")
#print(e)
self.buffer_receive_index = 0
raise crc_check_failed("CRC check failed!")
