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The GPS module for Arduino and Raspbery Pi is a small electronic circuit that allows to connect to your Arduino/Raspberry Pi board to get position and altitude, as well as speed, date and time on UTC (Universal Time Coordinated).
By default Raspbian configures the Raspberry Pi serial port (GPIO14-GPIO15) to provide boot-up information. It also allows you to login via a connected device. If you need to use the Pi’s serial port for something else (i.e. a specific add-on board) you will need to disable this default functionality.
It’s something I needed to do when I played with the Ciseco Pi-Lite and luckily isn’t too difficult as the instructions below will hopefully show.
Disable Login Via Serial Port
To disable the login feature we can run the following command to edit the inittab system file :
Use the cursor keys to find the line :
and add a # character at the beginning of the line to give :
Press “CTRL-X”, “Y” and finally “Enter” or “Return” to save the file.
Disable Boot Messages
When the Pi is booting all the debug messages are sent to the serial port. This can be useful for some purposes but we need to turn this off to free the port for our own use.
To stop the messages being sent to the port we need to edit another system file. Run the following command to edit the cmdline.txt file :
Use the cursor keys to find the line :
and remove the block of console parameters in the middle to give you :
Press “CTRL-X”, “Y” and finally “Enter” or “Return” to save. You should be returned to the command prompt.
Restart Pi
Now the changes have been made the Pi must be restarted for them to take effect.
Reboot using :
Test Using Minicom (optional)
If you have a suitable device (e.g. a PC) to connect to your Pi via a serial interface you can use the “Minicom” utility to send data to it via the Pi’s serial port. This is a quick way to test the configuration changes have been successful.
You can install Minicom using the following command :
Press “Y” when prompted.
You can then use Minicom to send and receive data over the serial port :
Pressing keys on your keyboard should result in them appearing on your connected device.
To exit Minicom press “CTRL-A”, then “X” and finally press “Return” to select “Yes” from the prompt.
Your serial port is now ready for whatever plans you have for it.