Python autobaud script for serial devices

autobaud.py

# This program was entirely written with ChatGPT 4, is untested, and should be
# considered alpha-quality software.
#
# Tom Keller, tom@tompkel.net, 2023
# To the maximum extent possible under law, I waive all copyright and related or
# neighboring rights to this work. This work is licensed under Creative Commons
# CC0, available at https://creativecommons.org/publicdomain/zero/1.0/legalcode
import sys
import argparse
import serial
import serial.tools.list_ports
from time import sleep

def read_serial(port, baudrate, bytesize, parity, stopbits, timeout=0.5, debug=False):
  if debug: print(f"Opening serial port {port} at {baudrate} baud")
  ser = serial.Serial(port, baudrate, bytesize, parity, stopbits, timeout=timeout)
  sleep(0.1)
  if debug: print(f"Sending newline character to {port}")
  ser.write(b'\n')
  sleep(0.1)
  data = ser.read(ser.in_waiting)
  if debug:
    print(f"Received {len(data)} bytes: {data}")
    print(f"Closing serial port {port}")
  ser.close()
  return data.decode('ascii', errors='strict')

def autobaud(port, baudrates, bytesize, parity, stopbits, retries=5, debug=False):
  for baudrate in baudrates:
    for retry in range(retries):
      try:
        response = read_serial(port, baudrate, bytesize, parity, stopbits,
                               debug=debug)
        if response: return baudrate, response
      except (serial.SerialException, UnicodeDecodeError) as e:
        if debug or retry == retries - 1:
          print(f"Error at {baudrate}: {str(e)}")
  return None, None

def main(args):
  parser = argparse.ArgumentParser(description="Autobaud script using pyserial")
  parser.add_argument("port", help="Serial port name")
  parser.add_argument("-b", "--baudrates", nargs="+", type=int,
                      default=[9600, 19200, 38400, 57600, 115200],
                      help="List of baud rates to try (default: [9600, 19200, 38400, 57600, 115200])")
  parser.add_argument("--bytesize", type=int, default=8,
                      help="Number of data bits (default: 8)")
  parser.add_argument("--parity", default="N", help="Parity (default: N)")
  parser.add_argument("--stopbits", type=int, default=1,
                      help="Number of stop bits (default: 1)")
  parser.add_argument("--debug", action="store_true",
                      help="Enable debug mode for additional logging")

  args = parser.parse_args(args)

  baudrate, response = autobaud(args.port, args.baudrates, args.bytesize,
                                args.parity, args.stopbits, debug=args.debug)

  if baudrate:
      if args.debug: print(f"Found intelligible response at {baudrate} baud: {response}\n\n")
      print(f"{baudrate}")
  else: print("Failed to find an intelligible response at the given baud rates")

if __name__ == "__main__":
  main(sys.argv[1:])