Working with Arduino

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

• Arduino Getting Started
• Setting Up the Development Environment
• Example
• Documentation Feedback

Arduino Getting Started

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

• Section 0: Getting to Know ESP32
• Section 1: Installing and Configuring Arduino IDE
• Section 2: Arduino Basics
• Section 3: Digital Output/Input
• Section 4: Analog Input
• Section 5: Pulse Width Modulation (PWM)
• Section 6: Serial Communication (UART)
• Section 7: I2C Communication
• Section 8: SPI Communication
• Section 9: Wi-Fi Basics
• Section 10: Web Server
• Section 11: Bluetooth
• Section 12: LVGL GUI Development
• Section 13: Comprehensive Project

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 the Development Environment

1. Install and Configure Arduino IDE

Please refer to the tutorial Install and Configure Arduino IDE to download and install the Arduino IDE and add ESP32 support.

The ESP32-S3-ETH requires Arduino ESP32 board support package version 2.0.12 or later. Select "ESP32S3 Dev Module" in the Boards Manager.

2. Install Dependency Libraries

The Arduino/libraries directory of the example package contains the required offline libraries. Libraries that are already indexed can also be installed via the Arduino IDE Library Manager.

Library Name	Purpose	Installation Method
Adafruit_NeoPixel	Controls the WS2812 RGB LED	Online or offline installation
ESP32-BLE-Keyboard	Bluetooth keyboard functionality	Online or offline installation
Ethernet	W5500 DHCP and static IP examples	Offline installation
Ethernet_Generic	Uses static IP after W5500 DHCP fails	Offline installation
ETHClass2	Ethernet camera example under Arduino ESP32 2.x	Offline installation

3. Arduino Project Settings

Select the following parameters in the "Tools" menu:

• Board: ESP32S3 Dev Module
• USB CDC On Boot: Enabled
• CPU Frequency: 240MHz (WiFi)
• Flash Size: 16MB (128Mb)
• Partition Scheme: Huge APP (3MB No OTA/1MB SPIFFS)
• PSRAM: OPI PSRAM
• Upload Mode: UART0 / Hardware CDC
• Upload Speed: 921600
• USB Mode: Hardware CDC and JTAG

Example

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

Example	Basic Description	Dependency Library
01_IO_Test	GPIO pin high/low level control	-
02_RGB_LED	GPIO pin controls WS2812 RGB LED	Adafruit NeoPixel
03_SD_Card	TF card mounting and file read/write	-
04_BLE_Keyboard	Bluetooth keyboard functionality demonstration	ESP32-BLE-Keyboard
05_WiFi_AP	Sets up an AP hotspot and displays connected device information	-
06_WiFi_STA	Connects to a Wi-Fi network and controls GPIO18 via a web page	-
07_WiFi_DHCP	Obtains an IP address via DHCP over Wi-Fi	-
08_WIFI_StaticIP	Uses a static IP address over Wi-Fi	-
09_WIFI_Web_CAM	Streams camera images over Wi-Fi	-
10_ETH_DHCP	Obtains an IP address via DHCP over Ethernet	Ethernet
11_ETH_StaticIP	Uses a static IP address over Ethernet	Ethernet
12_ETH_MAC_DHCP_StaticIP	Custom MAC address, uses a static IP address after DHCP fails	Ethernet_Generic
13_ETH_Web_CAM	Streams camera images over Ethernet	ETHClass2 (Arduino ESP32 2.x)

01_IO_Test

This example sets 19 GPIOs that can be used as outputs to high and low levels in sequence, with a 300 ms interval between each state change. The serial monitor displays the current GPIO number and level state synchronously.

Hardware Connection

Connect the development board to the computer using a USB cable. You can use a multimeter to measure the pin voltage, or connect an LED in series with a current-limiting resistor to observe level changes.

Key Configuration

The example controls the following GPIOs in sequence:

const int gpio_pin[] = {
  21, 17, 16, 18, 15, 3, 2, 1, 0, 44,
  43, 38, 39, 40, 41, 42, 45, 47, 48
};

Multiplexed Pins

GPIO33 to GPIO37 are occupied by onboard functions, and GPIO46 only supports input, so they are not included in the output test sequence. Some of the remaining GPIOs are multiplexed with onboard peripherals. Before testing GPIO outputs, disconnect the relevant peripherals to avoid bus conflicts.

Expected Behavior

The serial monitor displays the HIGH and LOW states of each GPIO in sequence. The high level of the ESP32-S3 is approximately 3.3 V, and the low level is approximately 0 V.

02_RGB_LED

This example controls the WS2812 RGB LED via GPIO21, demonstrating solid color fill, rainbow gradient, and theater chase effects in sequence.

Hardware Connection

Connect the development board to the computer using a USB cable. The RGB LED is already connected to GPIO21; no external wiring is required.

Expected Behavior

• Solid color fill: displays red, green, and blue in sequence.
• Theater chase: displays a dynamic chase effect in white, red, and blue.

03_SD_Card

This example mounts a TF card, creates waveshare.txt in the root directory, writes Hello world from Waveshare, lists the root directory files, and reads the file content.

tip

This example only supports the FAT32 file system by default; exFAT and NTFS are not supported. SDXC cards of 64 GB and above usually use the exFAT format by default, and must be backed up and reformatted to FAT32 before use. Formatting will erase all data on the card.

Hardware Connection

SPI Signal	ESP32-S3-ETH
CS (SS)	GPIO4
DI (MOSI)	GPIO6
DO (MISO)	GPIO5
SCK (SCLK)	GPIO7

Insert the TF card into the onboard card slot, then connect the development board to the computer using a USB cable.

Expected Behavior

The serial monitor displays the TF card mounting result, file write result, root directory file list, and the contents of waveshare.txt in sequence.

04_BLE_Keyboard

This example emulates the ESP32-S3-ETH as a BLE keyboard. The program is based on the ESP32-BLE-Keyboard open-source library.

Expected Behavior

After flashing the program, search for and connect to the development board in the Bluetooth settings of a computer or mobile device. Once connected, the development board can send example keystrokes or text.

05_WiFi_AP

This example configures the ESP32-S3-ETH as a Wi-Fi access point. The access point name is ESP32-S3-ETH, and the password is 88888888. When a device connects or disconnects, the serial monitor displays the device's MAC address and the DHCP-assigned IP address.

Expected Behavior

1. Flash the program and open the serial monitor.
2. Use a computer or mobile device to connect to the ESP32-S3-ETH hotspot.
3. Check the device MAC address and IP address output by the serial monitor.

06_WiFi_STA

This example configures the development board as a Wi-Fi station and starts an HTTP server. The browser page can view and toggle the output state of GPIO18.

Key Configuration

Before flashing, change the SSID and password in the program to match your current network parameters.

Expected Behavior

1. After the development board connects to Wi-Fi, the serial monitor displays the IP address.
2. Access that IP address in a browser.
3. Use the links on the page to toggle GPIO18 between high and low levels; the serial monitor synchronously displays /H or /L.

tip

If possible, refer to the figure below to connect an LED in series to visually check the GPIO18 level state, or measure it with a multimeter.

07_WiFi_DHCP

This example connects to the specified Wi-Fi network and automatically obtains an IP address via DHCP.

Key Configuration

Change the following parameters to the SSID and password of your current network:

const char *ssid = "Waveshare-AP";
const char *password = "88888888";

Expected Behavior

The serial monitor displays the Wi-Fi connection status and the DHCP-assigned IP address.

08_WIFI_StaticIP

This example connects to the specified Wi-Fi network using a static IP address.

Key Configuration

Modify the SSID, password, IP address, gateway, subnet mask, and DNS according to your current network:

IPAddress local_ip(192, 168, 196, 100);
IPAddress gateway(192, 168, 196, 1);
IPAddress subnet(255, 255, 255, 0);
IPAddress dns(192, 168, 196, 1);

Expected Behavior

The serial monitor displays the Wi-Fi connection status and the configured static IP address.

09_WIFI_Web_CAM

This example sets up a camera server over Wi-Fi to provide real-time images on the local network.

Camera Interface

Camera Signal	ESP32-S3-ETH
ENABLE	GPIO8
VSYNC	GPIO1
HREF	GPIO2
XCLK	GPIO3
PCLK	GPIO39
SIOD (SDA)	GPIO48
SIOC (SCL)	GPIO47
D7	GPIO18
D6	GPIO15
D5	GPIO38
D4	GPIO40
D3	GPIO42
D2	GPIO46
D1	GPIO45
D0	GPIO41

Key Configuration

Change the SSID and password in the program to match your current network parameters. After the camera initializes successfully, the program starts an HTTP video streaming server.

Expected Behavior

The serial monitor displays the camera server address. Access that address in a browser on the same local network to view the real-time image.

10_ETH_DHCP

This example initializes the onboard W5500 and obtains an IP address via DHCP after the Ethernet connection is established.

Ethernet Interface

W5500 Signal	ESP32-S3-ETH
MISO	GPIO12
MOSI	GPIO11
SCLK	GPIO13
CS	GPIO14
RST	GPIO9
INT	GPIO10

Expected Behavior

Connect the network cable and flash the program. The serial monitor displays the Ethernet initialization status and the DHCP-assigned IP address.

11_ETH_StaticIP

This example initializes the onboard W5500 and connects to Ethernet using the static IP address configured in the program.

Expected Behavior

Connect the network cable and flash the program. The serial monitor displays the Ethernet initialization status and the static IP address.

12_ETH_MAC_DHCP_StaticIP

This example allows you to customize the MAC address of the W5500. The program first attempts to obtain an IP address via DHCP; if DHCP fails, it uses a preset static IP address, such as 192.168.1.177.

Expected Behavior

Connect the network cable and flash the program. The serial monitor displays the IP address that is ultimately used.

13_ETH_Web_CAM

This example sets up a camera server over the onboard W5500 to provide real-time images on Ethernet. For the camera and W5500 interface definitions, refer to 09_WIFI_Web_CAM and 10_ETH_DHCP, respectively.

If not using PoE power, there is no need to connect an external PoE module; you can power the board via the USB Type-C interface.

Expected Behavior

The serial monitor displays the Ethernet connection status, MAC address, IP address, link speed, and camera server address. Access the server address in a browser on the same network to view the real-time image.

Documentation Feedback

If you encounter any issues during use, feel free to leave a comment.