I have a device with a USB serial port cable that I'd like to connect to my Raspberry Pi. The chipset for this USB to serial cable it the PL-2303 from Prolific Technology, Inc.
How can I read data from the serial connection of this device using Python?
To talk to a serial device using Python, use the pyserial module. If it is not available in your distribution, it can be installed by getting a copy of the source from the pyserial project page and running "python setup.py install"
Simple examples of using pyserial are available at the short introduction.
The module for the PL-2303 is available by default - see the firmware GitHub repository - when you plug the device in, you should see it fire up in /var/log/messages. I have connected up to an Arduino, and that "just worked" on communications port /dev/ttyUSB0 (different device, driver, chipset, etc., so your mileage may vary).
Download pySerial (https://pypi.python.org/pypi/pyserial)
wget http://pypi.python.org/packages/source/p/pyserial/pyserial-2.7.tar.gz?raw=true -O pyserial-2.7.tar.gz
tar -xzf pyserial-2.7.tar.gz
cd pyserial-2.7
sudo python setup.py install
You can check ttyUSB availability with the line
ls -ltr /dev|grep -i ttyUSB
To view the serial output use
tail -f /dev/ttyUSB<NUMBER FROM ABOVE>
To break out crtl+c
Create a testserial.py file paste this code
#!/usr/bin/python
from time import sleep
import serial
# Establish the connection on a specific port
ser = serial.Serial('/dev/ttyUSB0', 9600)
x = 1 while True:
print ser.readline() # Read the newest output
x += 1
The PL-2303 is well supported, and it will appear as /dev/ttyUSBx. No drivers are needed. Read it as you would any normal serial port. I haven't used Python, but in C++, I open() it in non-blocking mode, select() to see if there is data to be read, and then do a read().
Great tutorial for that :
http://www.digitalmihailo.com/post/usb-programming-with-python-on-linux
A valuable source of information is http://www.lvr.com/usbc.htm Complete
