Serial2.onReceive() not work.

[neolu]

Board

ESP32

Device Description

DevKitC

Hardware Configuration

#define RXD2 16
#define TXD2 17

Version

v2.0.4

IDE Name

Arduino IDE

Operating System

win10

Flash frequency

80

PSRAM enabled

yes

Upload speed

115200

Description

Serial2.onReceive() not work.

//Serial2.begin(baud-rate, protocol, RX pin, TX pin);
Serial2.begin(115200, SERIAL_8N1, RXD2, TXD2);
Serial2.onReceive(Serial2_callback);

void Serial2_callback() {
Serial.printf(".");
}

Sketch

Serial2.onReceive() not work.

  //Serial2.begin(baud-rate, protocol, RX pin, TX pin);
  Serial2.begin(115200, SERIAL_8N1, RXD2, TXD2);
  Serial2.onReceive(Serial2_callback);

void Serial2_callback() {
    Serial.printf(".");
}

Debug Message

Serial2.onReceive() not work.

  //Serial2.begin(baud-rate, protocol, RX pin, TX pin);
  Serial2.begin(115200, SERIAL_8N1, RXD2, TXD2);
  Serial2.onReceive(Serial2_callback);

void Serial2_callback() {
    Serial.printf(".");
}

Other Steps to Reproduce

Serial2.onReceive() not work.

//Serial2.begin(baud-rate, protocol, RX pin, TX pin);
Serial2.begin(115200, SERIAL_8N1, RXD2, TXD2);
Serial2.onReceive(Serial2_callback);

void Serial2_callback() {
Serial.printf(".");
}

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[SuGlider]

It seems that it works correctly, but the issue is actually that it doesn't work using the default pins...
I tried this and it worked fine:

void setup() {
Serial.begin(115200);

Serial2.begin(115200, SERIAL_8N1, 32, 33);
Serial2.onReceive(Serial2_callback);
}

void Serial2_callback() {
Serial.printf(".");
}

I will investigate why it doesn't work with just a Serial2.begin(115200);

[SuGlider]

I used 2 ESP32 for testing:

• ESP32 WROOM
• ESP32 WROVER-E

With both I used this Sketch:

void setup() {
  Serial.begin(115200);

  Serial2.begin(115200, SERIAL_8N1, 32, 33);
  Serial2.onReceive(Serial2_callback);
}

void Serial2_callback() {
  Serial.printf(".");
}

void loop() {
}

Connected RX0 pin (GPIO 3) to RX2 pin GPIO 32, as defined in the example sketch

Using Arduino IDE Serial Monitor, send anything to ESP32. RX0 pin will get the signal and it will pass the same signal to RX2 by the wire. This way Serial2.onReceive() will be activated.

ESP32 WROOM can use pins 16 and 17 for Serial2 (default RX2, TX2)

ESP32 WROVER-E can NOT use pins 16 or 17 because those are used to control PSRAM.

Thus, it only works with other pins, such as 32 an 33.