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UART

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:

/boot/Env.txt:

loglevel=10
overlays=uart2

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.