Overview

The ESP32-C3 is a low-power, high-integration 32-bit System-on-Chip (SoC) manufactured by Espressif Systems. Powered by an open-standard 32-bit single-core RISC-V (RV32IMC) microcontroller operating at up to 160 MHz160\text{ MHz}, it is designed as a pin-compatible, low-cost successor to the classic ESP8266.

Equipped with 400 KB400\text{ KB} of SRAM, 384 KB384\text{ KB} of ROM, integrated 2.4 GHz Wi-Fi (802.11 b/g/n), Bluetooth 5.0 (LE), and a native USB Serial/JTAG controller, it delivers secure connectivity (AES-128/256, RSA, ECC, and digital signatures) for budget smart home devices (ESPHome/Home Assistant, Matter).

Quick reference

CPU Core32-bit Single-Core RISC-V RV32IMC processor
Max Clock Frequency160 MHz160\text{ MHz}
SRAM400 KB400\text{ KB}
ROM384 KB384\text{ KB}
Flash MemoryEmbedded 4 MB4\text{ MB} (FN4/FH4) or external SPI Flash up to 16 MB16\text{ MB}
Operating Voltage (VDD)3.0 V to 3.6 V DC (3.3 V nominal)
Wireless SupportWi-Fi 802.11 b/g/n (up to 150 Mbps), Bluetooth 5.0 LE
On-Chip USBIntegrated USB Serial/JTAG Controller
GPIO Count22 I/O pins
ADC Channels6 channels (12-bit ADC)
Package32-pin QFN (5×5 mm5 \times 5\text{ mm}) / ESP32-C3 SuperMini PCB

Pinout (ESP32-C3 SuperMini Development Board Layout)

text
                       ┌─────────────┐
        (GPIO0 / ADC1_0) 1│ 1   16│ 5V (Power Input)
        (GPIO1 / ADC1_1) 2│       │15 GND
        (GPIO2 / ADC1_2) 3│ ESP32 │14 3V3 (3.3V Output)
        (GPIO3 / ADC1_3) 4│ -C3   │13 GPIO10
        (GPIO4 / ADC1_4) 5│ Super │12 GPIO9 (BOOT Button)
        (GPIO5 / ADC2_0) 6│ Mini  │11 GPIO8 (Onboard LED)
        (GPIO6 / SDA)    7│       │10 GPIO21 (TX)
        (GPIO7 / SCL)    8│       │9  GPIO20 (RX)
                       └─────────────┘

Specifications

ParameterSymbolMinTypMaxUnitConditions
Supply VoltageVDDV_{DD}3.03.33.6VDC supply
Wi-Fi Peak TX CurrentITXI_{TX}—290350mA802.11b, +21 dBm+21\text{ dBm}
Wi-Fi RX CurrentIRXI_{RX}—8290mA802.11g/n active
Deep Sleep CurrentIDSI_{DS}—515µARTC timer active
Light Sleep CurrentILSI_{LS}—130—µACPU paused
Max Output DriveIIOI_{IO}-28—+28mASingle GPIO pin

Example (Arduino ESP32 Core - Wi-Fi Scanner & Blinking LED)

cpp
#include <WiFi.h>

// Onboard LED on ESP32-C3 SuperMini is connected to GPIO8 (Active LOW)
const int ledPin = 8;

void setup() {
  pinMode(ledPin, OUTPUT);
  Serial.begin(115200);
  
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  delay(100);

  Serial.println("ESP32-C3 RISC-V Wi-Fi Scanner Ready!");
}

void loop() {
  digitalWrite(ledPin, LOW); // LED ON
  
  int n = WiFi.scanNetworks();
  Serial.printf("Found %d networks\n", n);
  for (int i = 0; i < n; ++i) {
    Serial.printf("%d: %s (%d dBm)\n", i + 1, WiFi.SSID(i).c_str(), WiFi.RSSI(i));
  }
  
  digitalWrite(ledPin, HIGH); // LED OFF
  delay(5000);
}

Common mistakes

  • Holding GPIO9 LOW during boot: GPIO9 is a strapping pin on the ESP32-C3. If held LOW during power-up or reset, the chip enters SPI flash download mode instead of booting normal user firmware.
  • Driving 5V signals directly into GPIOs: Unlike older AVR microcontrollers, ESP32-C3 GPIO pins are NOT 5V tolerant. Exceeding 3.6V on any I/O pin damages the chip.

Notes

  • ESP32-C3 vs ESP8266 vs ESP32-S3: ESP32-C3 is a single-core 160MHz RISC-V MCU with Wi-Fi + BLE 5; ESP8266 is an older 80MHz Tensilica MCU with Wi-Fi only; ESP32-S3 is a dual-core 240MHz Xtensa LX7 MCU with vector instructions for AI.

Assets & downloads