Pyserial read bytes return garbage values from serial port

Question

in my python programme , I am using PySerial library to read the data out as bytes from serial port. But most of the bytes are garbage values. I am giving the source as well as out come of the read bytes using this python module.

So can some please let me know (correct configuration settings) to read the correct values from the serial port using PySerial library? If not do we have any other serial library in Python where I can read the bytes without above issue.

import serial
import sys
import _thread
import serial.tools.list_ports
import threading


class SerialPort:
    ReceiveCallback: None

    def __init__(self):
        self.comportName = ""
        self.baud = 0
        self.timeout = None
        self.ReceiveCallback = None
        self.isopen = False
        self.receivedMessage = None
        self.serialport = serial.Serial()

    def __del__(self):
        try:
            if self.serialport.is_open():
                self.serialport.close()
        except:
            print("Destructor error closing COM port: ", sys.exc_info()[0])

    def RegisterReceiveCallback(self, aReceiveCallback):
        self.ReceiveCallback = aReceiveCallback
        try:
            ListnerThread = threading.Thread(target=self.SerialReadBytesThread)
            ListnerThread.start()
        except:
            print("Error starting Read thread: ", sys.exc_info()[0])

    def SerialReadlineThread(self):
        while True:
            try:
                if self.isopen:
                    self.receivedMessage = self.serialport.readline()
                    if self.receivedMessage != "":
                        self.ReceiveCallback(self.receivedMessage)
            except:
                print("Error reading COM port: ", sys.exc_info()[0])

    def SerialReadBytesThread(self):
        while True:
            try:
                if self.isopen:
                    size = self.serialport.inWaiting()
                    if size > 0:
                        readBytes = self.serialport.read(size)
                        self.receivedMessage = bytearray(readBytes)
                        if self.receivedMessage != b'':
                            self.ReceiveCallback(self.receivedMessage)
            except serial.SerialException as e:
                print("Error reading com port:", e.strerror)

    def IsOpen(self):
        return self.isopen

    def Open(self, portname, baudrate, timeout=0):
        if not self.isopen:
            # serialPort = 'portname', baudrate, bytesize = 8, parity = 'N', stopbits = 1, timeout = None, xonxoff = 0, rtscts = 0)
            self.serialport.port = portname
            self.serialport.baudrate = baudrate
            self.serialport.timeout = timeout
            try:
                self.serialport.open()
                self.isopen = True
                self.serialport.flushInput()
            except:
                print("Error opening COM port: ", sys.exc_info()[0])

    def Close(self):
        if self.isopen:
            try:
                self.serialport.close()
                self.isopen = False
            except:
                print("Close error closing COM port: ", sys.exc_info()[0])

    def Send(self, message):
        if self.isopen:
            try:
                # Ensure that the end of the message has both \r and \n, not just one or the other
                newmessage = message.strip()
                newmessage += '\r\n'
                self.serialport.write(newmessage.encode('utf-8'))
            except:
                print("Error sending message: ", sys.exc_info()[0])
            else:
                return True
        else:
            return False

    def GetComPort(vendorProductID):
        portName = " "
        ports = serial.tools.list_ports.comports()
        for port, des, hwID in ports:
            if vendorProductID in hwID:
                portName = port
                return portName
        return portName


if __name__ == '__main__':
    portName = SerialPort.GetComPort("VID:PID=0DB5:0180")
    comport = SerialPort()
    comport.Open(portName, 115200)
    t=threading.Thread(target=comport.SerialReadBytesThread)
    t.start()
    t.join()

Outcome read data from the Python module:

b'\x02\x02\x0e\x01\x0b\x010\x02A\x01\x17 \x19\t%\x11\x00\x11\xe3\xb0\xc4B\x98\xfc\x1c\x14\x9a\xfb\xf4\xc8\x99o\xb9$\'\xaeA\xe4d\x9b\x93L\xa4\x95\x99\x1bxR\xb8U\x01\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\x00\x03\xff\xff\xff\x01\x00\xb28\x04\x80\x08\xc0\x8a\x02\x00\x00\x00\x00\x00\x00\x00\x030\x00\x00\x00\x00\x00\x00\x01\x00\t%\x11\x00\x11<\x00i\x11\x00\x11\t%\x05rQ1909251100114Vx\x90 \txR"\x01S\x00\x00\x00\x01\x01A\x82\x02 \x00\x95\x05\x00\x00\x00\x00\x00\x9c\x01\x00_*\x02\tx_4\x01\x00\x9f\x02\x06\x00\x00\x00\x00\x01\x00\x9f\x03\x06\x00\x00\x00\x00\x00\x00\x9f\x10\x07\x06\r\n\x03\xa0 \x00\x9f\x1a\x02\x08@\x9f&\x08\x93?]\x8cL\xb1\x1b\xd4\x9f\'\x01\x80\x9f6\x02\x00\xc2\x9f7\x04\xc3\xe8\xee\xf9\x9f9\x01\x07\x9ff\x04\xa0\x00\xc0\x00\x9fn\x04 p\x00\x00\xcf\x01\x04W\x13I)Ew\x89\x17 \x06\xd2\x102\x01\x00\x13\x10\x00\x00\x00\x1f\x9a\x03\x19\t%\xdf\xdf#\x02\x08@\xdf\xdf\'\x01\x00\x00\x10\x92\xcf\xeb\x93\xb2\xe0\xfe\x00\x00,\x00$:\xd54\x14\x89\x96\x8b\t\xdb\xb9\xd4\xc9\xdb6}\x8e\x9eP\xc1?\x91a\xdd\x06~\xc8\xca\x85\xd8^\xa7\xda\xa9\x03\x03'

Expected value/Actual value: ( I did get this value from serial port snipping tool while running my python module)

02 02 0E 01 0B 01 30 02 41 01 17 20 19 09 25 11 02 10 E3 B0 C4 42 98 FC 1C 14 9A FB F4 C8 99 6F B9 24 27 AE 41 E4 64 9B 93 4C A4 95 99 1B 78 52 B8 55 01 00 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF 00 03 FF FF FF 01 00 B2 38 04 80 08 C0 8A 02 00 00 00 00 00 00 00 03 30 00 00 00 00 00 00 01 00 09 25 11 02 10 3C 00 6A 11 02 10 09 25 05 72 51 31 39 30 39 32 35 31 31 30 32 31 30 34 56 78 90 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 09 78 52 22 01 53 00 00 00 01 01 41 82 02 20 00 95 05 00 00 00 00 00 9C 01 00 5F 2A 02 09 78 5F 34 01 00 9F 02 06 00 00 00 00 01 00 9F 03 06 00 00 00 00 00 00 9F 10 07 06 0D 0A 03 A0 20 00 9F 1A 02 08 40 9F 26 08 EB 12 3F BB 4A 81 AB 37 9F 27 01 80 9F 36 02 00 C3 9F 37 04 0E D2 3B E0 9F 39 01 07 9F 66 04 A0 00 C0 00 9F 6E 04 20 70 00 00 CF 01 04 57 13 49 29 45 77 89 17 20 06 D2 10 32 01 00 13 10 00 00 00 1F 9A 03 19 09 25 DF DF 23 02 08 40 DF DF 27 01 00 00 10 92 CF
EB 93 B2 E0 FE 00 00 2D 00 24 B8 CD E0 22 A4 03 6E 2D D3 96 9E 0C 39 3A 6F 9C 01 45 88 F2 AC AF F2 C1 07 67 3F 07 52 16 FF 3D 26 35 03

Answer 1

It is basically the same when you encode your escaped byte string in HEX

02020e010b01300241011720190925110011e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b8550100ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff0003ffffff0100b238048008c08a02000000000000000330000000000000010009251100113c00691100110925057251313930393235313130303131345678902009785222015300000001014182022000950500000000009c01005f2a0209785f3401009f02060000000001009f03060000000000009f1007060d0a03a020009f1a0208409f2608933f5d8c4cb11bd49f2701809f360200c29f3704c3e8eef99f3901079f6604a000c0009f6e0420700000cf010457134929457789172006d21032010013100000001f9a03190925dfdf23020840dfdf270100001092cfeb93b2e0fe00002c00243ad5341489968b09dbb9d4c9db367d8e9e50c13f9161dd067ec8ca85d85ea7daa90303

You can convert bytes into hex by calling its hex method

hex_string=bytes.hex()