Can't communicate with Nextion display

[papaiatis]

Hi,

I've got a NodeMCU v0.9 and a 3.2" Nextion HMI display. The display uses UART for communication, eg.: change some text on the display.
What I would like to achieve: Using Arduino IDE, see debug information in Serial monitor. Communication between Nextion display and NodeMCU is also a serial communication.

A simplified version of my sketch looks like this:

#include "SoftwareSerial.h"
SoftwareSerial nextionSerial(D9, D10); // NodeMCU D9 and D10 pins
void setup() {
    Serial.begin(115200);
    nextionSerial.begin(9600);
}
void loop() {
    while (nextionSerial.available()) {
        Serial.write(nextionSerial.read());
    }
}

If I touch a button on the Nextion display it sends data to its Serial ports, which I should be able to read in Serial Monitor using the code above, but I see nothing.

Any clue on what's wrong?

Thank you!

[juancgalvez]

This post could clarify your issue.