ESP32 serial never becomes available

Other Hardware 3rd Party Boards
1

Hi!

I have an ESP-WROOM-32 chip where I have placed a jumper between RX2 and TX2 in the hopes of seeing data being transmitted from TX2 to RX2.

In order to test it, I have the following code

#define RXD2 16
#define TXD2 17
void setup() {
 Serial.begin(115200);
 Serial2.begin(115200, SERIAL_8N1, RXD2, TXD2);
 delay(1000);
 Serial.println("Loopback program started");
}
void loop() {
 if(Serial.available()){
   Serial.write("-");
   Serial2.write(Serial.read());  
 }
 if(Serial2.available()){
   Serial.write(".");
   Serial.write(Serial2.read());  
 }
}

But looking at the output I get(see attachment), it doesn't look like anything is transmitted over the RX2 and TX2 pins. Serial and Serial2 never even becomes available.
I am connected to the device via USB and have selected FireBeetle-ESP32 in the Arduino IDE since that's what I've seen recommended in various places.

What am I missing?

screenshot
screenshot1920×910 124 KB

/Mads

2

What characters are you sending via Serial, and how?

3

As seen on the code above, it’s just .’s and -‘s and writing between the two serial ports. I have added a jumper between RX2 and TX2.

4

The wiring is understood.

Where do the characters come from? Are you trying to send them using the serial monitor?

If so, you will have an easier time using a terminal program like TeraTerm or PuTTY.

5

And this is of course the crux of the problem. I assume that the Serial.println in the setup would be enough to cause Serial.available() to be truthy. I don’t send other characters then what is seen in the code. Tried connecting via the terminal and was able write to Serial and get the expected feedback.

Thanks!

6

No, the TX and RX channels are completely independent.

7

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