ESP32-S3

What is the ESP32-S3?

The ESP32-S3 is a Wi-Fi + Bluetooth 5 LE microcontroller from Espressif, and the most capable member of the ESP32 family for makers. It keeps the familiar dual-core, 240 MHz design but moves to Xtensa LX7 cores with vector instructions for AI, and adds native USB, more pins and fast octal PSRAM.

Most people meet it on the ESP32-S3-DevKitC-1 board shown below. It carries an ESP32-S3-WROOM-1 module, two USB-C ports, an addressable RGB LED and 44 header pins. It programs in the Arduino IDE, ESP-IDF or MicroPython, and is the chip behind many camera, voice and smart-display boards.

A map of the DevKitC-1: the WROOM-1 module holds the chip, flash and PSRAM; the two USB-C ports are “USB” (native) and “UART” (bridge).

Inside the ESP32-S3 Chip

One chip holds two application cores, a low-power RISC-V co-processor, memory, a 2.4 GHz radio, crypto engines and a long list of peripherals, including USB, LCD and camera interfaces the original ESP32 never had.

The ESP32-S3 SoC: 2 × LX7 + vector unit, 512 KB SRAM, a Wi-Fi/BLE 5 radio, and peripherals; flash, PSRAM and antenna sit beside it in the module.

• Two Xtensa LX7 cores at up to 240 MHz. Arduino runs your loop() on core 1 and Wi-Fi on core 0.
• Vector (SIMD) instructions accelerate neural-network maths for face detection, wake words and TinyML.
• ULP co-processors (RISC-V and FSM) can read sensors while the main cores sleep.
• 512 KB SRAM + 384 KB ROM, plus 16 KB of RTC memory that survives deep sleep.
• Security: secure boot, flash encryption and AES/SHA/RSA/HMAC accelerators.

The ESP32-S3-WROOM-1 Module & What “N16R8” Means

You rarely solder the bare chip. The WROOM-1 module packs the chip, flash, PSRAM, crystal and antenna under a metal shield, and its part number tells you the memory.

Reading ESP32-S3-WROOM-1-N16R8: N16 = 16 MB flash, R8 = 8 MB octal PSRAM, -1 = PCB antenna (-1U = external antenna).

Full ESP32-S3-DevKitC-1 Pinout

Here is the complete ESP32-S3-DevKitC-1 pinout: all 44 header pins on J1 and J3, each with its GPIO number, ADC channel, touch channel and special functions (UART, I2C, SPI, USB, JTAG, strapping and PSRAM).

Every DevKitC-1 pin: J1 (3V3, RST, GPIO3–18, 46, 5V) on the left and J3 (TX/RX, GPIO0–2, 19–21, 35–48) on the right.

Want the short version first? These cards group the pins by job:

The ESP32-S3 at a glance. Note there is no DAC on the S3.

Every Pin Explained

The S3 has a GPIO matrix, so most functions can move to almost any pin. What follows are the fixed functions and the Arduino defaults you'll use every day.

Power & control pins

Which ESP32-S3 Pins Are Safe to Use?

This is the question everyone asks. Some pins set the boot mode, some carry USB or serial, and some are taken by the flash and PSRAM. Here is the short answer:

Green is safe, amber needs care, blue should be avoided on R8 modules, and red is used internally and not on the headers.

Powering the ESP32-S3

The DevKitC-1 takes 5 V from either USB-C port or the 5V pin; an LDO regulator makes the 3.3 V the chip runs on.

Any 5 V source → 3.3 V LDO → the ESP32-S3 and the 3V3 pins. The GPIO are 3.3 V only.

Native USB: the S3's Superpower

Unlike the original ESP32, the S3 has USB built into the chip. That's why the DevKitC-1 has two USB-C ports.

UART port → bridge → UART0. USB port → straight into the chip's USB OTG and USB Serial/JTAG controller.

• USB CDC serial: set USB CDC On Boot = Enabled and Serial prints over the native port.
• USB devices: keyboard, mouse, gamepad, MIDI or a USB flash drive (MSC) with USB Mode = USB-OTG (TinyUSB).
• Built-in JTAG: debug with breakpoints over the same cable, no external probe needed.

ADC & Capacitive Touch

Two 12-bit ADCs give 20 analog channels, and 14 pins double as touch pads. One surprise if you're coming from the ESP32: on the S3, touch readings go up when touched.

ADC: 0–~3.1 V → 0–4095. Touch: the reading rises above a threshold when a finger is near.

Use analogReadMilliVolts() for factory-calibrated millivolts, and keep analog sensors on ADC1 (GPIO1–10) if your sketch uses Wi-Fi. Explore bit depth with the ADC Resolution Calculator. There is no DAC on the S3; use PWM with an RC filter or an external I2S DAC.

PWM with LEDC

The LEDC peripheral gives 8 PWM channels on any output pin, with frequency and resolution you choose (up to 14 bits).

Duty cycle sets the average voltage. Core 3.x: ledcAttach(pin, freq, bits) then ledcWrite(pin, duty).

UART, I2C & SPI Default Pins

These are the pins the Arduino core uses when you don't specify any. Thanks to the GPIO matrix you can pass other pins to Wire.begin(sda, scl), SPI.begin(sck, miso, mosi, ss) or Serial1.begin(baud, SERIAL_8N1, rx, tx).

UART0 43/44, UART1 17/18, I2C 8/9, SPI 11/13/12/10. I2S and TWAI (CAN) go on any pins you choose.

Many I2C modules need pull-ups; size them with the Pull-up Resistor Calculator.

Wi-Fi & Bluetooth 5 LE

One 2.4 GHz radio handles Wi-Fi 802.11 b/g/n (station, access point, or both) and Bluetooth 5 LE with long-range and 2 Mbps modes.

STA, AP, BLE 5 and ESP-NOW. There is no Bluetooth Classic, so no BluetoothSerial or A2DP audio.

Edge AI & Camera

The feature that gives the S3 its reputation: vector instructions plus PSRAM and a camera interface let a $5 chip run small neural networks offline.

Camera → PSRAM → vector AI → result → LCD or Wi-Fi. Libraries: ESP-DL, ESP-WHO, ESP-SR, TensorFlow Lite Micro.

Power Modes & Deep Sleep

For battery projects, deep sleep drops the chip from hundreds of mA to about 8 µA. Wake it with a timer, a GPIO, a touch pad or the ULP co-processor.

Chip currents on a log scale. A whole DevKit draws more in sleep (LDO, LEDs, USB bridge); bare-module designs get closest to 8 µA.

How to Upload Code to the ESP32-S3

Install the Espressif core, choose ESP32S3 Dev Module, set flash and PSRAM for your module, and upload over either USB-C port.

Write → compile → USB-C → download mode → ROM loader writes flash → run.

ESP32-S3 vs ESP32 vs ESP32-C3

Three popular Espressif chips, three different sweet spots.

Pick the S3 for AI, camera, displays or USB; the ESP32 for Bluetooth Classic or a DAC; the C3 for low-cost, low-power Wi-Fi.

Coming from an Arduino Uno? The S3 is 15× faster with 250× the RAM and built-in wireless, but it runs at 3.3 V instead of 5 V.

Code Examples (Arduino-ESP32 core 3.x)

Five short sketches covering the features you'll use most.

1. Colour the on-board RGB LED

void setup() {}
void loop() {
  rgbLedWrite(RGB_BUILTIN, 40, 0, 0);  delay(500);   // red   (core 2.x: neopixelWrite)
  rgbLedWrite(RGB_BUILTIN, 0, 40, 0);  delay(500);   // green
  rgbLedWrite(RGB_BUILTIN, 0, 0, 40);  delay(500);   // blue
}

2. Read calibrated millivolts

void setup() { Serial.begin(115200); }
void loop() {
  int mv = analogReadMilliVolts(4);        // GPIO4 = ADC1_CH3 (works with Wi-Fi)
  Serial.printf("%d mV\n", mv);
  delay(500);
}

3. Touch pad (value rises when touched)

const int PAD = 1;                         // T1 = GPIO1
uint32_t idle;
void setup() { Serial.begin(115200); idle = touchRead(PAD); }
void loop() {
  uint32_t v = touchRead(PAD);
  if (v > idle * 1.3) Serial.println("Touched!");  // S3: higher = touched
  delay(100);
}

4. Fade an LED with LEDC PWM

void setup() { ledcAttach(5, 5000, 12); }   // GPIO5, 5 kHz, 12-bit
void loop() {
  for (int d = 0; d <= 4095; d += 16) { ledcWrite(5, d); delay(2); }
  for (int d = 4095; d >= 0; d -= 16) { ledcWrite(5, d); delay(2); }
}

5. Deep sleep with a timer wake-up

RTC_DATA_ATTR int boots = 0;                // kept in RTC memory through deep sleep
void setup() {
  Serial.begin(115200); delay(500);
  Serial.printf("Boot #%d\n", ++boots);
  esp_sleep_enable_timer_wakeup(10 * 1000000ULL);  // 10 s
  esp_deep_sleep_start();
}
void loop() {}

Beginner Mini-Projects

Four complete builds, from a first blink to a Wi-Fi web switch and a USB keyboard.

Project 1 wiring: LED + 220 Ω on GPIO2, plus the on-board RGB LED. Check values with the LED resistor calculator.

void setup() { pinMode(2, OUTPUT); }
void loop() {
  digitalWrite(2, HIGH); rgbLedWrite(RGB_BUILTIN, 0, 0, 40); delay(500);
  digitalWrite(2, LOW);  rgbLedWrite(RGB_BUILTIN, 0, 0, 0);  delay(500);
}

#include <WiFi.h>
#include <WebServer.h>
WebServer server(80);
void setup() {
  Serial.begin(115200); pinMode(2, OUTPUT);
  WiFi.begin("my-ssid", "password");
  while (WiFi.status() != WL_CONNECTED) delay(300);
  Serial.println(WiFi.localIP());
  server.on("/on",  [](){ digitalWrite(2, HIGH); server.send(200, "text/plain", "LED ON");  });
  server.on("/off", [](){ digitalWrite(2, LOW);  server.send(200, "text/plain", "LED OFF"); });
  server.begin();
}
void loop() { server.handleClient(); }

#include "USB.h"
#include "USBHIDKeyboard.h"
USBHIDKeyboard Keyboard;
void setup() { pinMode(0, INPUT_PULLUP); Keyboard.begin(); USB.begin(); }
void loop() {
  if (digitalRead(0) == LOW) {
    Keyboard.println("Hello from ESP32-S3!");
    delay(500);                                   // simple debounce
  }
}

void setup() {
  Serial.begin(115200); delay(500);
  Serial.println("Woke up!");
  rgbLedWrite(RGB_BUILTIN, 0, 40, 0); delay(1000);
  rgbLedWrite(RGB_BUILTIN, 0, 0, 0);
  touchSleepWakeUpEnable(T1, 40000);           // threshold: tune from touchRead()
  esp_deep_sleep_start();
}
void loop() {}

ESP32-S3 Specifications

The key numbers at a glance.

Flash and PSRAM depend on the module variant (N8, N8R8, N16R8…).

Key Terms — Glossary

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Frequently Asked Questions

Quick answers to the questions people ask most about the ESP32-S3.

Conclusion & Key Takeaways

The ESP32-S3 is the go-to Espressif chip when a project needs more than Wi-Fi: AI, a camera, a display or USB. It also stays friendly to program in the Arduino IDE.

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