RSB-3730 UART（RS-232/RS-485）

How to Config RS232 or RS485 Mode

COM Name	Device Node	Remark
UIO2 com1	/dev/ttymxc0	support RS232
COM1/DEBUG2	/dev/ttymxc1	Debug Port
COM	/dev/ttymxc2	support RS232/RS485
UIO2 com4	/dev/ttymxc3	support RS232

Enter U-boot interrupt mode  Connect device to debug port, and open debug console.
Press "ctrl + c" key before power up the device, until get the following information on debug console:

Hit any key to stop autoboot: 0
=> <INTERRUPT>
=>

Then you can input the following cammand to config UART mode.

RS485 Mode：

=> setenv uart_mode 2:1
=> saveenv
=> reset

RS232 Mode：

=> setenv uart_mode 2:0
=> saveenv
=> reset

Note：The default value is RS232.

The above command "setenv uart_mode 2:1", 2:1 means to set ttymxc2 to RS485 standard mode, and 2:0 means to set ttymxc2 to RS232 mode.
The following RS232 testing method is shared by "/dev/ttymxc0, /dev/ttymxc2, /dev/ ttymxc3",and only needs to be replaced Uart Name.

RS232- Loopback Test

# stty -F /dev/ttymxc0 -echo -onlcr 115200
# cat /dev/ttymxc0 &
# echo "Serial Port Test" > /dev/ttymxc0

RS-485 Test