Working with Arduino

This chapter contains the following sections. Please read as needed:

Arduino Getting Started
Setting Up Development Environment
Example

Arduino Getting Started

New to Arduino ESP32 development and looking for a quick start? We have prepared a comprehensive Getting Started Tutorial for you.

Note: This tutorial uses the ESP32-S3-Zero as a reference example, and all hardware code is based on its pinout. Before you start, we recommend checking the pinout of your development board to ensure the pin configuration is correct.

Setting Up Development Environment

1. Installing and Configuring Arduino IDE

Please refer to the tutorial Installing and Configuring Arduino IDE to download and install the Arduino IDE and add ESP32 support.

Installation Steps: For installation methods, please refer to: Arduino Library Management Tutorial.

2. Example

The Arduino examples are located in the Arduino directory of the example package.

Example	Basic Description
01_GPIO	Control the logic level of the exposed GPIO pins
02_BlinkRGB	Implement a breathing LED effect on the RGB LED
03_GetchipID	Obtain and print ESP32-C5 chip hardware information every three seconds, including chip model, revision, core count, and chip ID
04_BLE	Use the ESP32-C5-Zero development board to connect to BLE beacons and receive broadcast data
05_UART	Implement UART communication using the ESP32-C5-Zero development board
06_WIFI_AP	Configure the ESP32-C5-Zero development board as an AP hotspot (2.4G), allowing other Wi-Fi devices to connect
07_WIFI_STA	Connect to a specified Wi-Fi network, print connection information, fetch weather data via an API, and support automatic reconnection upon Wi-Fi disconnection
08_WIFI_StaticIP	Use the ESP32-C5-Zero development board to connect to Wi-Fi with a static IP address

01_GPIO

Code

01_GPIO.ino

void loop() {
  REG_WRITE(GPIO_OUT_REG, REG_READ(GPIO_OUT_REG) ^ gpio_low);
  REG_WRITE(GPIO_OUT1_REG, REG_READ(GPIO_OUT1_REG) ^ gpio_high);
  delay(300);
}

Code Analysis

REG_WRITE() combined with REG_READ() toggles the GPIO output registers bitwise, allowing multiple pins to change state simultaneously.
delay(300) controls the toggling rhythm, making it easier to observe with external LEDs or an oscilloscope.

02_BlinkRGB

Code

02_BlinkRGB.ino

void loop() {
  static uint8_t wheel_pos = 0;      // Current color position (0-255)
  static uint32_t last_update_ms = 0;

  const uint32_t now = millis();

  if (now - last_update_ms >= 20) {
    last_update_ms = now;

    // Calculate and set the color
    set_wheel_color(wheel_pos);

    // Increment position and wrap around at 255
    wheel_pos++; 
  }
}

Code Analysis

set_wheel_color(wheel_pos) computes an RGB color based on the current wheel position and writes it to the onboard LED.
wheel_pos++ continuously increments the color index, creating a smooth color‑cycling effect with a 20ms refresh interval.

Operation Result

03_GetchipID

Code

03_GetchipID.ino

void loop() {
  const uint64_t mac = ESP.getEfuseMac();
  uint32_t chip_id = 0;
  for (uint8_t i = 0; i < 24; i = (uint8_t)(i + 8)) {
    chip_id |= (uint32_t)(((mac >> (40 - i)) & 0xff) << i);
  }

  Serial.printf("ESP32-C5-Zero Chip model = %s Rev %d\n", ESP.getChipModel(), ESP.getChipRevision());
  Serial.printf("This chip has %d cores\n", ESP.getChipCores());
  Serial.print("Chip ID: ");
  Serial.println(chip_id);
  delay(3000);
}

Code Analysis

ESP.getEfuseMac() reads the factory‑flashed MAC address of the chip and further combines it into a simplified chip_id.
The code outputs the chip model, revision, and core count via the serial port, making it easy to quickly identify the current board.

Operation Result

04_BLE

Code

04_BLE.ino

void setup() {
  Serial.begin(115200);

  NimBLEDevice::init("ESP32-C5-Zero");

  NimBLEAdvertising *advertising = NimBLEDevice::getAdvertising();

  NimBLEAdvertisementData scan_response;
  scan_response.setName("ESP32-C5-Zero");   // This is the name shown on the phone
  advertising->setScanResponseData(scan_response);

  const bool ok = advertising->start();
  if (ok) {
    Serial.println("BLE advertising started");
  }else{
    Serial.println("BLE advertising start failed");
  }
}

Code Analysis

NimBLEDevice::init() initializes the BLE stack and sets the device name shown during advertising.
advertising->start() starts advertising, allowing the board to be discovered by phones or other BLE devices.

Operation Result

05_UART

Code

05_UART.ino

void loop() {
  while (Serial1.available() > 0) {
    Serial1.write(Serial1.read());
  }
  delay(1);
}

Code Analysis

Serial1.available() checks whether new data is present in the UART receive buffer.
Any data read is immediately sent back via Serial1.write(), implementing a basic serial loopback test.

Operation Result

06_WIFI_AP

Code

06_WIFI_AP.ino

void setup() {
  Serial.begin(115200);

  // Best practice: Register the event handler BEFORE starting the AP 
  // so you don't miss any immediate connection events.
  WiFi.onEvent(on_wifi_event);

  // Start the Access Point
  Serial.println("Starting WiFi Access Point...");
  if (!WiFi.softAP(ssid, password)) {
    Serial.println("Failed to start WiFi AP! Halting system.");
    while (true); // Halt if AP fails to start
  }

  Serial.println("WiFi Access Point initialized successfully!");
  Serial.print("AP SSID: ");
  Serial.println(ssid);
  Serial.print("AP IP Address: ");
  Serial.println(WiFi.softAPIP()); // Also print the AP's own IP address
}

Code Analysis

WiFi.softAP(ssid, password) starts the access point mode, making the development board work as a Wi‑Fi hotspot.
WiFi.softAPIP() reads the hotspot's local IP address, facilitating subsequent connection testing with phones or computers.

Operation Result

07_WIFI_STA

Code

07_WIFI_STA.ino

void setup() {
  // Initialize serial communication
  Serial.begin(115200);
  while (!Serial);  // Wait for serial port to connect

  // Connect to WiFi
  Serial.println("Connecting to WiFi...");
  WiFi.begin(ssid, password);
  
  // Wait for WiFi connection
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  
  // Print connection success message with WiFi details
  Serial.println("\n");
  Serial.println("=====================================");
  Serial.println("WiFi connection successful!");
  Serial.print("Connected to SSID: ");
  Serial.println(ssid);
  Serial.print("With password: ");
  Serial.println(password);
  Serial.print("Assigned IP address: ");
  Serial.println(WiFi.localIP());
  Serial.println("=====================================\n");
}

Code Analysis

WiFi.begin(ssid, password) attempts to connect to the specified router, with a loop that continuously checks the connection status.
After a successful connection, WiFi.localIP() prints the assigned IP address to confirm network connectivity.

Operation Result

08_WIFI_StaticIP

Code

08_WIFI_StaticIP.ino

void loop() {
  static uint32_t last_check_ms = 0;
  const uint32_t now = millis();
  if ((uint32_t)(now - last_check_ms) < 5000) {
    delay(10);
    return;
  }
  last_check_ms = now;

  // Periodically check Wi-Fi connection and auto-reconnect
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("Wi-Fi disconnected, attempting reconnection...");
    WiFi.begin(ssid, password); // Re-initiate connection
    uint8_t retry = 0;
    uint32_t retry_start_ms = millis();
    uint32_t retry_dot_ms = retry_start_ms;
    while (WiFi.status() != WL_CONNECTED && retry < 5) {
      const uint32_t now2 = millis();
      if ((uint32_t)(now2 - retry_dot_ms) >= 1000) {
        retry_dot_ms = now2;
        Serial.print('.');
        retry++;
      }
      delay(10);
    }
    if (WiFi.status() == WL_CONNECTED) {
      Serial.println("\nReconnected to Wi-Fi!");
      Serial.print("Current IP: ");
      Serial.println(WiFi.localIP());
    }
  }
  delay(10);
}

Code Analysis

This code checks the network connection status every 5 seconds to avoid frequent reconnection attempts in the main loop.
When the Wi‑Fi is disconnected, it re‑calls WiFi.begin() to initiate a new connection and prints the current IP address upon successful reconnection.

Operation Result

Give Feedback

Arduino Getting Started​

Setting Up Development Environment​

1. Installing and Configuring Arduino IDE​

2. Example​

01_GPIO​

Code​

Code Analysis​

02_BlinkRGB​

Code​

Code Analysis​

Operation Result​

03_GetchipID​

Code​

Code Analysis​

Operation Result​

04_BLE​

Code​

Code Analysis​

Operation Result​

05_UART​

Code​

Code Analysis​

Operation Result​

06_WIFI_AP​

Code​

Code Analysis​

Operation Result​

07_WIFI_STA​

Code​

Code Analysis​

Operation Result​

08_WIFI_StaticIP​

Code​

Code Analysis​

Operation Result​

Arduino Getting Started

Setting Up Development Environment

1. Installing and Configuring Arduino IDE

2. Example

01_GPIO

Code

Code Analysis

02_BlinkRGB

Code

Code Analysis

Operation Result

03_GetchipID

Code

Code Analysis

Operation Result

04_BLE

Code

Code Analysis

Operation Result

05_UART

Code

Code Analysis

Operation Result

06_WIFI_AP

Code

Code Analysis

Operation Result

07_WIFI_STA

Code

Code Analysis

Operation Result

08_WIFI_StaticIP

Code

Code Analysis

Operation Result