UART example

Neutis has 5 available UART ports:

Port Device TX Pin RX Pin
UART0 /dev/ttyS0 PA4 PA5
UART1 /dev/ttyS1 PG6 PG7
UART2 /dev/ttyS2 PA0 PA1
UART3 /dev/ttyS3 PA13 PA14
S_UART /dev/ttyS4 PL2 PL3

In this example, we are going to perform a loopback test by sending data to a TX pin and receiving on the RX pin of the UART2 port.

Firstly, short the UART2 pins PA0 and PA1 as shown in the picture:

Then enable it by applying UART2 Device Tree overlay. Open /boot/Env.txt and edit it so as it should look like this:



Reboot and log in to your device. Now we need to change terminal line settings to disable echoing back every character typed, otherwise, you will get endless data loop from /dev/ttyS2:

stty -echo -F /dev/ttyS2

Print on the standard output every character you type:

cat /dev/ttyS2

Log in to Neutis in another terminal and write something to /dev/ttyS2:

echo "hello" > /dev/ttyS2

In the first terminal, you should get what you typed.