[Question]UART serial communication problem

Haiang

Hello friends
Currently I am using dmg80480c070_04wtr screen, this screen I have set to TTL mode and has 4 pins TX2, RX2, TX4, RX4
I cannot interface UART pin TX2 and RX2 or pin TX4 and RX4 pin with TX0 and RX0 pin of Mega 2560 board
I have connected 5V power to LCD
The LCD's GND is connected to the Mega2560 Circuit
I connected the TX2 LCD pin to the RX0 Mega 2560
LCD RX2 pin I connect to TX0 Mega 2560
I use the software DGUS_V7647
- If I interface Mega 2560 with LCD using USB HDL662B at data transfer rate 9600 on the computer, it turns on and off. Relay
- But if I communicate at 9600 or 115200 speed on LCD, I cannot turn Relay on or off.
- I also set up T5LCFG file but it still doesn't work
- Below are some pictures that I took, and the program I wrote, I can't figure out what the cause is.

dw涂涂

Hello, you can use USB HDL662B to connect the LCD to the computer. After installing the driver, use a serial port tool to issue a command to read the version number. If there is a response, it indicates normal communication. The attachment includes serial port tools and drivers; If there is no response, it indicates abnormal communication. You can flash the CFG file provided in the attachment and test the communication again