ESP32-S3 DevKitC-1: Two USB Ports, PSRAM, the RGB LED and the Pins Best Left Alone

About the board

The ESP32-S3 is a dual-core 240 MHz Xtensa LX7 with Wi-Fi 4, Bluetooth 5 LE, vector instructions for neural networks and native USB. The ESP32-S3-DevKitC-1 board has 44 pins, two USB-C ports and a WS2812 RGB LED. It is the best pick for cameras, LVGL displays, voice recognition and USB devices: keyboards, MIDI controllers, flash drives.

Which USB port

The board has two connectors:

• UART — through a CP2102N/CH343 bridge. It always works, even with a "broken" firmware, and resets the board into the bootloader by itself.
• USB — the chip's own native USB (GPIO19/20). You need it for USB HID (USB.h, USBHIDKeyboard), MIDI and MSC. To see Serial here, enable Tools → USB CDC On Boot → Enabled.

For a first try use the UART port.

Modules and PSRAM

The module marking tells you the memory: N8R8 is 8 MB flash and 8 MB PSRAM, N16R8 is 16 and 8, N8 has no PSRAM. In modules with octal PSRAM (R8), pins GPIO35, 36 and 37 belong to the memory — do not use them, even though they are on the header. GPIO26–32 always belong to the flash. In the Arduino IDE enable PSRAM with Tools → PSRAM → OPI PSRAM.

The pinout in short

Safe for anything: GPIO4–7, 15–18, 21, 38–42, 47.

The RGB LED

The on-board LED is an addressable WS2812, so digitalWrite() on GPIO48 does nothing... almost. The arduino-esp32 3.x core defines RGB_BUILTIN and intercepts digitalWrite(RGB_BUILTIN, HIGH), switching on white. For colours there is rgbLedWrite():

// ESP32-S3: the on-board RGB LED without any library
void setup() {
  Serial.begin(115200);
}

void loop() {
  rgbLedWrite(RGB_BUILTIN, 40, 0, 0);   // red (0–255 per channel; 40 is already bright)
  delay(500);
  rgbLedWrite(RGB_BUILTIN, 0, 40, 0);   // green
  delay(500);
  rgbLedWrite(RGB_BUILTIN, 0, 0, 40);   // blue
  delay(500);
  digitalWrite(RGB_BUILTIN, LOW);       // off
  delay(500);
}

Touch on the S3 works the other way round

On the classic ESP32 touchRead() drops under a finger (from about 70 to about 20). On the S3 the values are large — tens of thousands — and rise when touched. A sketch written for the ESP32 with touchRead(T0) < 30 never triggers on an S3. Calibrate at start-up and compare with the idle level: touchRead(pin) > baseline * 1.3. Also note that the S3 has no T0, and the touch channel number equals the GPIO number.

Try it in the simulator

Pick ESP32-S3 DevKitC-1 in the list next to the examples. Try the touch dimmer — it is adapted to rising touch values and the RGB LED — or the web server.

Good to know

• Current. With Wi-Fi active the S3 draws peaks of up to 500 mA. A weak USB hub is a common cause of resets with Brownout detector was triggered.
• Camera. Boards with a camera connector (ESP32-S3-EYE, XIAO ESP32S3 Sense) use the same modules; a camera requires PSRAM.
• Speed. The S3 vector instructions speed up ESP-NN and TensorFlow Lite Micro several times over the classic ESP32.