Personal tools

StarSBC-6ULL RS232 example

From SomLabs Wiki

Jump to: navigation, search

StarSBC-6ULL RS232 example


Contents

This tutorial shows how to send and receive data using RS232 interface on StarSBC-6ULL with communication extension board SLH2-comm. The default Yocto image contains all required software tools.

Loop test

The SLH2-comm extension board has two RS232 interfaces available so they may be connected to perform the test in a loop. All signals are available on the J101 and J201 connectors. They should be connected according to the following table:

RS232-1 signal RS232-2 signal
RS232-1 TXD (J101 pin 3) RS232-2 RXD (J201 pin 8)
RS232-1 RXD (J101 pin 4) RS232-2 TXD (J201 pin 7)
RS232-1 CTS (J101 pin 1) RS232-2 RTS (J201 pin 10)
RS232-1 RTS (J101 pin 2) RS232-2 CTS (J201 pin 9)
StarSBC-6ULL-SLH2-rs232.jpg

Both interfaces are already defined in the default module device-tree and are recognized as /dev/ttymxc2 and /dev/ttymxc6 devices. The device files may be used directly for reading and writing and the bitrate may be set using the stty tool:

root@starsbc-6ull:~# stty -F /dev/ttymxc2 9600 crtscts
root@starsbc-6ull:~# stty -F /dev/ttymxc6 9600 crtscts
root@starsbc-6ull:~# cat /dev/ttymxc2 &
[1] 465
root@starsbc-6ull:~# echo "123" > /dev/ttymxc6
123
NXP Partner ST Partner Renesas Partner