Documentation

// XIAO ESP32-C3 - Blink an external LED on D0
// Board: "XIAO_ESP32C3" in the Arduino IDE (esp32 core)

#define LED_PIN D0   // GPIO2

void setup() {
  pinMode(LED_PIN, OUTPUT);
}

void loop() {
  digitalWrite(LED_PIN, HIGH);
  delay(250);
  digitalWrite(LED_PIN, LOW);
  delay(250);
}

// XIAO ESP32-C3 - Scan for nearby Wi-Fi networks
// Prints SSID, RSSI, and encryption type to Serial Monitor.

#include <WiFi.h>

void setup() {
  Serial.begin(115200);
  delay(500);
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  delay(100);
  Serial.println("Wi-Fi scan starting...");
}

void loop() {
  int n = WiFi.scanNetworks();
  Serial.printf("Found %d networks:\n", n);
  for (int i = 0; i < n; i++) {
    Serial.printf("  %2d) %-32s  %4d dBm  %s\n",
                  i + 1,
                  WiFi.SSID(i).c_str(),
                  WiFi.RSSI(i),
                  WiFi.encryptionType(i) == WIFI_AUTH_OPEN ? "OPEN" : "ENC");
  }
  Serial.println();
  delay(5000);
}

// XIAO ESP32-C3 - I2C Bus Scanner
// SDA = D4 (GPIO6), SCL = D5 (GPIO7)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  while (!Serial) {}
  Wire.begin();   // Defaults to SDA=GPIO6, SCL=GPIO7 on XIAO ESP32-C3
  Serial.println("\nI2C Scanner");
}

void loop() {
  byte found = 0;
  for (byte addr = 1; addr < 127; addr++) {
    Wire.beginTransmission(addr);
    if (Wire.endTransmission() == 0) {
      Serial.printf("  Found device at 0x%02X\n", addr);
      found++;
    }
  }
  Serial.printf("%d device(s) found.\n\n", found);
  delay(2000);
}

# XIAO ESP32-C3 - MicroPython BLE Advertise
# Flash the official MicroPython ESP32-C3 firmware, then run this.

import bluetooth
from time import sleep

ble = bluetooth.BLE()
ble.active(True)

name = b"XIAO-C3"
adv = bytearray(b'\x02\x01\x06')              # Flags: LE general discoverable
adv += bytes([len(name) + 1, 0x09]) + name    # Complete local name

ble.gap_advertise(100_000, adv_data=adv)
print("Advertising as", name.decode())

while True:
    sleep(1)