Hello Forum, I’m having an issue with my Nextion display where it doesn’t respond to any serial commands sent via TX/RX. I’ve tested multiple microcontroller boards, including Arduino-based ones, and the problem persists. I verified all connections: TX on the microcontroller to RX on the Nextion, RX on the microcontroller to TX on the Nextion, proper GND connection, and correct power supply. I tried various baud rates, sent basic commands like bauds=9600 or page-switching commands, and ensured my microcontroller’s TX/RX pins were working by testing them with other devices. Using a logic analyzer, I confirmed no data was being transmitted from the Nextion display. While the static UI preloaded via the Nextion Editor works fine, any attempt to modify elements dynamically through serial communication fails. I also swapped microcontrollers, cables, and power sources, but the issue persists. If anyone has experienced this or has suggestions on how to fix it, I would really appreciate the help. Thank you!
This can be a Hardware or a Software issue. Unfortunately, you don’t write which exact Nextion model you are using.
Your idea to swap microcontrollers as a differential diagnose was good, basically, you should do the same at the other end of the line - take another Nextion out of the drawer (where the ambitious developer has always 2 or 3 spares) and try with these.
But even before, you can check the Nextion’s UART hardware in a simple way: connect it directly to the computer via the Nextion Foca Max Board or any other USB to TTL UART adapter and try to upload a simple tft file via the Nextion Editor’s upload function. If that does work, you can be sure that the Nextion’s serial communication is - technically - ok and you might look into your HMI code where the serial communication is blocked.
Another thing to look into, but that’s almost self understanding, is to check if between the MCU and the Nextion, not only the RX and TX lines are well connected (and crossed!), but that both have also their GND pins connected, so that there is a common reference potential.