VAR-SOM-AM43 RS485-Port

RS-485 port

Please do the following to enable and test RS-485 port:
1. Perform a loopback at RS-485 port by shorting pins 1 to 3 and 2 to 4 on J11 (on the carrier board).

2. Type the following commands in the Linux shell to enable:

$ echo 168 > /sys/class/gpio/export
$ echo "out" > /sys/class/gpio/gpio168/direction
$ echo 0 > /sys/class/gpio/gpio168/value

# Tx enable: gpio173

$ echo 173 > /sys/class/gpio/export
$ echo "out" > /sys/class/gpio/gpio173/direction
$ echo 1 > /sys/class/gpio/gpio173/value

3.start minicom

$ minicom -D/dev/ttyO2 -b115200 -8

4. Type a few characters at the minicom and see that the loopback is working.