The BeagleBone Black has six on-board serial ports but only one is enabled by default: the
/dev/ttyO0 device that is coupled to the serial console, as we saw in the previous chapters. The other serial ports must be enabled before they can be used.
If we do log in to the system, we can easily verify this using the following command:
root@BeagleBone:~# ls -l /dev/ttyO* crw-rw---- 1 root tty 248, 0 Apr 23 20:20 /dev/ttyO0
/dev/ttyO0 device is the only available serial port.
To enable the other serial ports, we need to modify the kernel settings in order to ask it to enable the serial port we wish to use. Which ports need to be enabled depends on the pins we'd like to use to connect our device. The...