Accessing serial port via CGI script

Prerequisites:

• Part 3: Using Serial Port on Universal Expansion Board

• Python CGI script with lighttpd (Root privileges are required)

1. Install pyserial on RaspberryPi

a. Download pyserial-2.5.tar.gz (106.3 kB)
b. unzipping and untaring

gunzip pyserial-2.5.tar.gz
tar -xvf pyserial-2.5.tar

c. Install pySerial

cd pyserial-2.5
sudo python setup.py install

2.Testing

Saving following python CGI scripts to your CGI folder.

Filename: shows.py

#!/usr/bin/python
import os
ser = os.popen("sudo python stest.py").readlines() 
# print "Content-Type: text/html"
# print
print ser[0]
print ser[2]

Filename: stest.py

#!/usr/bin/python
import serial
serialport = serial.Serial("/dev/ttyAMA0",9600,timeout=0.5)
serialport.write("\r")
response = serialport.readlines(None)
serialport.write("version\r")
response = serialport.readlines(None)

print response[1]
print response[2]

The python CGI script shows.py will acquire and return the Version Information of the Shell(This shell is a part of my real time operating system) which runs on the serial port of the STM32 MCU.