EPC-R5710 Serial Port（RS-232、RS-422、RS-485）

For COM serial port pin definition, please refer to previous chapter 2.4 for more information.
Self connect the TXD and RXD of each COM port

RS-232 loopback Test

Step 1:  description
COM2 and COM3 need to be configured under uboot as either of 232, 485, 422 modes
Example both as 232:

COM Port	node
COM2	/dev/ttymxc2
COM3	/dev/ttymxc3

u-boot=> setenv uart_mode 2:0,3:0
u-boot=> saveenv
Saving Environment to MMC...Writing to MMC(2)...<span style="color:#1abc9c;">OK</span>
u-boot=> reset

Step 2: Example com2 test :

# stty -F /dev/ttymxc2 -echo -onlcr 115200
# cat /dev/ttymxc2 &
# echo "Serial Port Test" > /dev/ttymxc2
Serial Port Test

Example com3 test:

# stty -F /dev/ttymxc3 -echo -onlcr 115200
# cat /dev/ttymxc3 &
# echo "okk" > /dev/ttymxc3
okk