CODEWITHSUNDEEP
pythonpyserial
Kris
Kris

Reputation: 77

pyserial: loop through baud rates

I have written the following bit of code to test various baud rates of a serial connection to a router. Essentially, bit-banging until I hopefully find the write one.


import serial
from time import sleep

baud_dict = [2400, 4800, 9600, 14400, 19200, 2800, 38400, 57600, 76800, 115200, 230400]

for baud_rate in baud_dict:
    print("Trying baud rate of: " + str(baud_rate))
    ser = serial.Serial('/dev/ttyUSB0', baud_rate, timeout=1)
    print(ser)
    ser.write('\r'.encode())
    sleep(3)
    read_val = ser.read(size=64)
    ser.close()
    print(read_val)
    sleep(5)

The result when running this script is the first baud rate is tested and returns output from the remote side. When the next baud rate is tested, an Input/Output execution is raised. I have combed through the pyserial documentation and do not believe I am doing anything wrong. Is there a different method I should look at to close the serial connection before moving onto the next one?

Here is the output:

Trying baud rate of: 2400
Serial<id=0x7fb080c6f358, open=True>(port='/dev/ttyUSB0', baudrate=2400, bytesize=8, parity='N', stopbits=1, timeout=1, xonxoff=False, rtscts=False, dsrdtr=False)
b''
Trying baud rate of: 4800
Traceback (most recent call last):
  File "bitbang.py", line 8, in <module>
    ser = serial.Serial('/dev/ttyUSB0', baud_rate, timeout=1)
  File "/home/kris/Desktop/serial_bitbang/lib/python3.5/site-packages/serial/serialutil.py", line 240, in __init__
    self.open()
  File "/home/kris/Desktop/serial_bitbang/lib/python3.5/site-packages/serial/serialposix.py", line 286, in open
    self._update_dtr_state()
  File "/home/kris/Desktop/serial_bitbang/lib/python3.5/site-packages/serial/serialposix.py", line 634, in _update_dtr_state
    fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_DTR_str)
OSError: [Errno 5] Input/output error

Upvotes: 2

Views: 2119

Answers (1)

Hao Li
Hao Li

Reputation: 1762

I run your code succeed. But you can try this:

import serial
from time import sleep

baud_dict = [2400, 4800, 9600, 14400, 19200, 2800, 38400, 57600, 76800, 115200, 230400]

ser = serial.Serial('/dev/ttyS0', timeout=1)
for baud_rate in baud_dict:
    print("Trying baud rate of: " + str(baud_rate))
    ser.baudrate = baud_rate
    print(ser)
    ser.write('\r'.encode())
    sleep(3)
    read_val = ser.read(size=64)
    print(read_val)
    sleep(5)
ser.close()

Upvotes: 2

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