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.

2. Installing Libraries

To run the example, you need to install the corresponding library. The example program package for the ESP32-C6-LCD-0.85 development board can be downloaded from here. The Arduino\libraries directory within this package contains all the necessary library files required for this tutorial.

Library or File Name	Description	Version	Installation Method
lvgl	LVGL graphics library	v8.4.0 or v9.3.0	Via Library Manager or manual install
GFX_Library_for_Arduino	GFX graphics library	v1.6.0	Via Library Manager or manual install
U8g2	Graphics display library	v2.35.30	Via Library Manager or manual install
FastLED	RGB LED driver library	v3.10.1	Via Library Manager or manual install
ESP32-audioI2S-master	Audio processing library	v3.4.0	Via Library Manager or manual install
OneButton	Button library	v2.6.1	Via Library Manager or manual install

Version Compatibility Notes

There are strong dependencies between versions of LVGL and its driver libraries. For example, a driver written for LVGL v8 may not be compatible with LVGL v9. To ensure that the examples can be reproduced reliably, it is recommended to use the specific versions listed in the table above. Mixing different versions of libraries may lead to compilation failures or runtime errors.

Installation Steps:

Extract the downloaded example package.
Copy all folders (ESP32-audioI2S-master, GFX_Library_for_Arduino, etc.) from its Arduino\libraries directory to the Arduino libraries folder.

info
The path to the Arduino libraries folder is typically: c:\Users\<username>\Documents\Arduino\libraries.
You can also locate it in the Arduino IDE by going to File > Preferences and checking the "Sketchbook location". The libraries folder is the libraries subfolder within this path.
For other installation methods, please refer to: Arduino Library Management Tutorial.

Required Board Installation Instructions for ESP32-C6-LCD-0.85

Board Name	Installation Requirement	Version Requirement
ESP32 by Espressif Systems	"Install Offline" / "Install Online"	3.2.0

3. Other Tips

For the ESP32-C6-LCD-0.85, you need to select and configure the board.

Select the ESP32C6 Dev Module for ESP32-C6-LCD-0.85.
Select the USB port.
The ESP32-C6-LCD-0.85 uses the ESP32-C6 native USB interface, not a UART-to-USB bridge. For serial communication:
- The printf() function can be used directly;
- To use the Serial.println() function, additional configuration is required: Enable the "USB CDC On Boot" option in the IDE's Tools menu, or declare an HWCDC object in your code to handle USB serial communication.
Select 8MB Flash
Select a Partition Table of the appropriate size

Example

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

Example	Basic Description	Dependency Library
01_audio_out	Read audio files from TF card and play them	ESP32-audioI2S-master
02_button_example	Button test	OneButton
03_ws2812b_example	Test RGB LED	FastLED
04_gfx_helloworld	Display HelloWorld on the screen	GFX_Library_for_Arduino
05_esp_wifi_analyzer	Display WiFi signal strength on the screen	GFX_Library_for_Arduino
06_gfx_u8g2_font	Display text in multiple languages by loading fonts	GFX_Library_for_Arduino, U8g2
07_sd_card_test	Test TF card read/write	---
08_lvgl_example_v8	lvgl v8.4.0 example	GFX_Library_for_Arduino, lvgl
09_lvgl_example_v9	lvgl v9.3.0 example	GFX_Library_for_Arduino, lvgl

01_audio_out

This example demonstrates the ESP32-C6-LCD-0.85 playing audio through a speaker; the screen shows no output.

Code Analysis

Set I2S pins:

void setupI2S() {
  i2s.setPins(I2S_BCK_PIN, I2S_LRCK_PIN, I2S_DOUT_PIN, I2S_DIN_PIN, I2S_MCK_PIN);
  // Initialize the I2S bus in standard mode
  if (!i2s.begin(I2S_MODE_STD, EXAMPLE_SAMPLE_RATE, I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_MONO, I2S_STD_SLOT_LEFT)) {
    Serial.println("Failed to initialize I2S bus!");
    return;
  }
}

Set the audio data to be played:

i2s.write((uint8_t *)audio_data, AUDIO_SAMPLES * 2);

Operation Result

The device will play auido directly without showing content on the screen

02_button_example

This example demonstrates how to use the OneButton library to read button states such as single click, double click, and long press, and print them via the serial monitor.

Code Analysis

Bind callback functions:

button1.attachClick(click1);
button1.attachDoubleClick(doubleclick1);
button1.attachLongPressStart(longPressStart1);
button1.attachLongPressStop(longPressStop1);
button1.attachDuringLongPress(longPress1);

Operation Result

The screen shows no output
Button information is printed to the serial monitor

03_ws2812b_example

This example uses the FastLED library to drive the ws2812b RGB LED on the ESP32-C6-LCD-0.85, changing to a random color every 500ms.

Code Analysis

Initialize ws2812b and set brightness:

FastLED.addLeds<WS2812B, DATA_PIN, RGB>(leds, NUM_LEDS);  // GRB ordering is typical
FastLED.setBrightness(100); // 0-255

Operation Result

The screen shows no output
The RGB LED changes to a random color every 500ms

04_gfx_helloworld

This example demonstrates the ESP32-C6-LCD-0.85 using the GFX_Library_for_Arduino library to drive the screen and display "HelloWorld" on the screen.

Code Analysis

Configure the screen interface and screen resolution, etc.

Arduino_DataBus *bus = new Arduino_HWSPI(3 /* DC */, 5 /* CS */, 1 /* SCK */,  2/* MOSI */, GFX_NOT_DEFINED /* MISO */);
Arduino_GFX *gfx = new Arduino_ST7735(bus, 4 /* RST */, 0 /* rotation */, true /* IPS */,128 /* width */, 128 /* height */,2 /* col offset 1 */, 3 /* row offset 1 */);

Operation Result

The screen displays as follows:

05_esp_wifi_analyzer

This example demonstrates the ESP32-C6-LCD-0.85 using a GFX_Library_for_Arduino library to display the signal strength of the WiFi band

Operation Result

The screen displays as follows:

06_gfx_u8g2_font

This example demonstrates how ESP32-C6-LCD-0.85 uses GFX_Library_for_Arduino libraries to load font libraries to display them in various languages

Operation Result

The screen displays as follows:

07_sd_card_test

This example tests the TF card read/write functionality on the ESP32-C6-LCD-0.85.

Code

07_sd_card_test.ino

#include "FS.h"
#include "SD_MMC.h"

int clk = 16;
int cmd = 15;
int d0 = 17;
int d1 = 18;
int d2 = 13;
int d3 = 14;

void listDir(fs::FS &fs, const char *dirname, uint8_t levels) {
  Serial.printf("Listing directory: %s\n", dirname);

  File root = fs.open(dirname);
  if (!root) {
    Serial.println("Failed to open directory");
    return;
  }
  if (!root.isDirectory()) {
    Serial.println("Not a directory");
    return;
  }

  File file = root.openNextFile();
  while (file) {
    if (file.isDirectory()) {
      Serial.print("  DIR : ");
      Serial.println(file.name());
      if (levels) {
        listDir(fs, file.path(), levels - 1);
      }
    }else{
      Serial.print("  FILE: ");
      Serial.print(file.name());
      Serial.print("  SIZE: ");
      Serial.println(file.size());
    }
    file = root.openNextFile();
  }
}

void createDir(fs::FS &fs, const char *path) {
  Serial.printf("Creating Dir: %s\n", path);
  if (fs.mkdir(path)) {
    Serial.println("Dir created");
  }else{
    Serial.println("mkdir failed");
  }
}

void removeDir(fs::FS &fs, const char *path) {
  Serial.printf("Removing Dir: %s\n", path);
  if (fs.rmdir(path)) {
    Serial.println("Dir removed");
  }else{
    Serial.println("rmdir failed");
  }
}

void readFile(fs::FS &fs, const char *path) {
  Serial.printf("Reading file: %s\n", path);

  File file = fs.open(path);
  if (!file) {
    Serial.println("Failed to open file for reading");
    return;
  }

  Serial.print("Read from file: ");
  while (file.available()) {
    Serial.write(file.read());
  }
}

void writeFile(fs::FS &fs, const char *path, const char *message) {
  Serial.printf("Writing file: %s\n", path);

  File file = fs.open(path, FILE_WRITE);
  if (!file) {
    Serial.println("Failed to open file for writing");
    return;
  }
  if (file.print(message)) {
    Serial.println("File written");
  }else{
    Serial.println("Write failed");
  }
}

void appendFile(fs::FS &fs, const char *path, const char *message) {
  Serial.printf("Appending to file: %s\n", path);

  File file = fs.open(path, FILE_APPEND);
  if (!file) {
    Serial.println("Failed to open file for appending");
    return;
  }
  if (file.print(message)) {
    Serial.println("Message appended");
  }else{
    Serial.println("Append failed");
  }
}

void renameFile(fs::FS &fs, const char *path1, const char *path2) {
  Serial.printf("Renaming file %s to %s\n", path1, path2);
  if (fs.rename(path1, path2)) {
    Serial.println("File renamed");
  }else{
    Serial.println("Rename failed");
  }
}

deleteFile(fs::FS &fs, const char *path) {
  Serial.printf("Deleting file: %s\n", path);
  if (fs.remove(path)) {
    Serial.println("File deleted");
  }else{
    Serial.println("Delete failed");
  }
}

void testFileIO(fs::FS &fs, const char *path) {
  File file = fs.open(path);
  static uint8_t buf[512];
  size_t len = 0;
  uint32_t start = millis();
  uint32_t end = start;
  if (file) {
    len = file.size();
    size_t flen = len;
    start = millis();
    while (len) {
      size_t toRead = len;
      if (toRead > 512) {
        toRead = 512;
      }
      file.read(buf, toRead);
      len -= toRead;
    }
    end = millis() - start;
    Serial.printf("%u bytes read for %lu ms\n", flen, end);
    file.close();
  }else{
    Serial.println("Failed to open file for reading");
  }

  file = fs.open(path, FILE_WRITE);
  if (!file) {
    Serial.println("Failed to open file for writing");
    return;
  }

  size_t i;
  start = millis();
  for (i = 0; i < 2048; i++) {
    file.write(buf, 512);
  }
  end = millis() - start;
  Serial.printf("%u bytes written for %lu ms\n", 2048 * 512, end);
  file.close();
}

void setup() {
  Serial.begin(115200);
  delay(3000);
  if (!SD_MMC.setPins(clk, cmd, d0, d1, d2, d3)) {
    Serial.println("Pin change failed!");
    return;
  }
  if (!SD_MMC.begin()) {
    Serial.println("Card Mount Failed");
    return;
  }
  uint8_t cardType = SD_MMC.cardType();

  if (cardType == CARD_NONE) {
    Serial.println("No SD_MMC card attached");
    return;
  }

  Serial.print("SD_MMC Card Type: ");
  if (cardType == CARD_MMC) {
    Serial.println("MMC");
  } else if (cardType == CARD_SD) {
    Serial.println("SDSC");
  } else if (cardType == CARD_SDHC) {
    Serial.println("SDHC");
  }else{
    Serial.println("UNKNOWN");
  }

  uint64_t cardSize = SD_MMC.cardSize() / (1024 * 1024);
  Serial.printf("SD_MMC Card Size: %lluMB\n", cardSize);

  listDir(SD_MMC, "/", 0);
  createDir(SD_MMC, "/mydir");
  listDir(SD_MMC, "/", 0);
  removeDir(SD_MMC, "/mydir");
  listDir(SD_MMC, "/", 2);
  writeFile(SD_MMC, "/hello.txt", "Hello ");
  appendFile(SD_MMC, "/hello.txt", "World!\n");
  readFile(SD_MMC, "/hello.txt");
  deleteFile(SD_MMC, "/foo.txt");
  renameFile(SD_MMC, "/hello.txt", "/foo.txt");
  readFile(SD_MMC, "/foo.txt");
  testFileIO(SD_MMC, "/test.txt");
  Serial.printf("Total space: %lluMB\n", SD_MMC.totalBytes() / (1024 * 1024));
  Serial.printf("Used space: %lluMB\n", SD_MMC.usedBytes() / (1024 * 1024));
}

void loop() {
  delay(10);
}

Code Analysis

TF card initialization:

if (!SD_MMC.setPins(clk, cmd, d0, d1, d2, d3)) {
    Serial.println("Pin change failed!");
    return;
  }
  if (!SD_MMC.begin()) {
    Serial.println("Card Mount Failed");
    return;
  }

Operation Result

The screen shows no output
Open the serial monitor

08_lvgl_example_v8

This example demonstrates how to run the lvgl examples (v8.4.0) on the ESP32-C6-LCD-0.85.

It is required to install lvgl v8.4.0 version. If you have installed other version, please reinstall.

Operation Result

The screen displays as follows:

09_lvgl_example_v9

This example demonstrates how to run the lvgl (v9.3.0) examples on the ESP32-C6-LCD-0.85.

It is required to install lvgl v9.3.0 version. If you have installed other version, please reinstall.

Operation Result

The screen displays as follows:

Give Feedback

Arduino Getting Started​

Setting Up Development Environment​

1. Installing and Configuring Arduino IDE​

2. Installing Libraries​

3. Other Tips​

Example​

01_audio_out​

Code Analysis​

Operation Result​

02_button_example​

Code Analysis​

Operation Result​

03_ws2812b_example​

Code Analysis​

Operation Result​

04_gfx_helloworld​

Code Analysis​

Operation Result​

05_esp_wifi_analyzer​

Operation Result​

06_gfx_u8g2_font​

Operation Result​

07_sd_card_test​

Code​

Code Analysis​

Operation Result​

08_lvgl_example_v8​

Operation Result​

09_lvgl_example_v9​

Operation Result​

Arduino Getting Started

Setting Up Development Environment

1. Installing and Configuring Arduino IDE

2. Installing Libraries

3. Other Tips

Example

01_audio_out

Code Analysis

Operation Result

02_button_example

Code Analysis

Operation Result

03_ws2812b_example

Code Analysis

Operation Result

04_gfx_helloworld

Code Analysis

Operation Result

05_esp_wifi_analyzer

Operation Result

06_gfx_u8g2_font

Operation Result

07_sd_card_test

Code

Code Analysis

Operation Result

08_lvgl_example_v8

Operation Result

09_lvgl_example_v9

Operation Result