By standard the UART interface is configured as serial console. If you want to use the UART interface for other things, e.g. for a GPS module, the standard function needs to be deactivated.
- Open the cmdline.txt file with the Nano text editor.
sudo nano /boot/cmdline.txt
and remove the following part from the file.
The content of the file should look like this
dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait
Exit the editor with
xand save the changes using
- Open inittab
sudo nano /etc/inittab
and search for the following line.
T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100
#at the beginning of the line to comment this line. Doing so the line should look like this.
#T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100
Exit the editor the same ways as in the previous step.
- From Kernel 3.18.x on the following step must be excecuted aditionally.
sudo nano /boot/config.txt
Search for the following line and remove the
#at the beginning of the line.
Exit the editor the same ways as in the previous step.Show kernel version
- Restart RPI.