ESP32 Forum

Posted: **Sun Mar 11, 2018 1:02 am**

I have found examples of basic arduino to arduino serial communication but have been unable to get those working between ESP32 boards. The two are connected:

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esp1   esp2
gnd to gnd
tx2 to rx2
rx2 to tx2

Simple sketches:

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//transmit sketch
void setup() {
  Serial.begin(9600);
}

void loop() {
  Serial.println("test...");
  delay(1000);
}

//receive sketch
void setup() {
  Serial.begin(9600);
}

void loop() {
  String received = "";
  while (Serial.available())
  {
    received = Serial.read();
    Serial.println(received);
  }
}

What else is required to make this work? I have also tried sharing vcc/vin between them.

Thanks

Posted: **Wed Mar 21, 2018 3:40 pm**

You are using the Serial 2 on the ESP32 (it has 3). In order to use this you have to define a global object (outside of the setup or loop functions):

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HardwareSerial Serial2(2);

Then, to refer to this serial port, instead of using

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Serial

use

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Serial2

For examble:

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Serial.available()

is replaced by

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Serial2.available()

Posted: **Mon Aug 08, 2022 11:27 am**

Receiving Code :
#define RXp2 16
#define TXp2 17
void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
Serial2.begin (SERIAL_8N1, RXp2,TXp2);
}
void loop() {
Serial.println("Message Received: ");
Serial.println(Serial2.readString());

}

Sending Code:

void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
Serial2.begin(SERIAL_8N1, 16,17);

}

void loop() {
Serial.println("Hello");

Tried a lot of versions of these codes, want to serially communicate between two ESP32 boards but unable to do so. The receiving code works fine with arduino but not with ESP32. What changes should I make in order to establish communication?

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