[SOLVED] Nextion 3.2" communication

Hi!

I'm trying to make my NX4024T032 work with Mega 2560.

Connected the screen to a 5V/1A external power supply.

Nextion connected to Serial2 right now, but also tried 1 and 3.
(Mega TX2 -> Nex RX
Nex TX -> Mega RX2)

Problem:

  • Nex sends data to Mega (RX2) correctly
  • but if I send data from Mega (TX2) it arrives back to Mega (RX2), like it would be shorted on Nex side :frowning:

I've tried Nex examples, but even nexInit() returns error (which means command was not confirmed by Nex)

So I made a simple code trying to test com:

void setup(void)
{    
  Serial2.begin(9600);
  Serial.begin(9600);
}

bool datasent=false;
void loop(){
  if(!datasent)
  {
    delay(3000);
    setT0Text("Incoming");
    datasent=true;
  }
}

void serialEvent2()
{
  while(Serial2.available())
  {
    char inChar = (char)Serial2.read();

    if((byte)inChar == 0xFF)
    {
      Serial.println("");
      Serial.println("---0xFF---");
    }
    else
    {
    Serial.print(inChar);
    }
  }
}

void setT0Text(String message)
{
  while(Serial2.available())
  {
    Serial2.read();
  }
  Serial2.print("t0.txt=");
  Serial2.print("\"");
  Serial2.print(message);
  Serial2.print("\"");
  Serial2.write(0xFF);
  Serial2.write(0xFF);
  Serial2.write(0xFF);
}

My nextion sends a postinitialize message, that arrives to Mega fine.
But my setT0Text function is also returned by the SerialEvent2 and Nex does nothing meanwhile.

I would appreciate any suggestion.

Thanks,
Chris

Problem solved... only required a jumper wire between the power supply GND and Arduino GND, because those must be common LoL...