🛠 Console sur l'USB-C natif (USB-Serial/JTAG)

Objectives

Unlike the classic ESP32, the ESP32-C3 integrates a USB-Serial/JTAG controller: the board's USB-C port communicates directly with the chip, without an external UART bridge (CP2102/CH340). You will learn how to use Serial over this native USB, how to avoid blocking when no terminal is open, and you will get a glimpse of JTAG debugging via the same port.

Hardware

• 1 ESP32-C3 board with native USB-C
• 1 USB-C data cable
• Serial terminal (Arduino IDE, PuTTY, or "screen")

Complete code

void setup {
  Serial.begin(115200);            // sur C3 : Serial = USB-Serial/JTAG
  Serial.setTxTimeoutMs(0);        // ne JAMAIS bloquer si terminal ferme
  delay(1000);                     // laisse le temps d'ouvrir le terminal
  Serial.println(F("Bonjour depuis l'USB natif du ESP32-C3"));
  Serial.printf("Coeurs : %d, flash : %u Mo\n",
                1, ESP.getFlashChipSize / 1048576);
}

void loop {
  if (Serial.available) {
    String s = Serial.readStringUntil('\n');
    s.trim;
    Serial.println(s);             // echo de ce que vous tapez
  }
  delay(2);
}

Expected verification

Opening the terminal at 115200 bauds and then resetting the board displays the welcome message and "Cores: 1, flash: 4 MB". Everything you type is echoed back, passing through the same USB-C cable used for flashing.

Common errors

• No visible output: without a terminal open at startup, the USB-Serial/JTAG has no host; setTxTimeoutMs(0) prevents the program from hanging on printf calls.
• Double use of the port: during a flash or an OpenOCD (JTAG) session, the serial port is occupied; close the terminal before reflashing.
• Assuming Serial = UART0: on C3 boards with an additional chip (DevKitM-1 with CP2102), you must select USB CDC On Boot in the Tools menu to switch to native USB.
• Entry-level board without native USB wired: verify that the connector is properly connected to the D+/D- pins of the ESP32-C3.