Arduino as an ESP-IDF component

This method is recommended for advanced users. To use this method, you will need to have the ESP-IDF toolchain installed.

For a simplified method, see Installing using Boards Manager.

ESP32 Arduino lib-builder

If you don’t need any modifications in the default Arduino ESP32 core, we recommend you to install using the Boards Manager.

Arduino Lib Builder is the tool that integrates ESP-IDF into Arduino. It allows you to customize the default settings used by Espressif and try them in Arduino IDE.

For more information see Arduino lib builder

Installation

Note

Latest Arduino Core ESP32 version is now compatible with ESP-IDF v4.4. Please consider this compatibility when using Arduino as a component in ESP-IDF.

  1. Download and install ESP-IDF.

  2. Create a blank ESP-IDF project (use sample_project from /examples/get-started) or choose one of the examples.

  3. In the project folder, create a new folder called components and clone this repository inside the newly created folder.

mkdir -p components && \
cd components && \
git clone https://github.com/espressif/arduino-esp32.git arduino && \
cd arduino && \
git submodule update --init --recursive && \
cd ../.. && \
idf.py menuconfig

Note

If you use Arduino with ESP-IDF often, you can place the arduino folder into global components folder.

If you’re targeting the ESP32-S2 or ESP32-S3 and you want to use USBHID classes such as USBHID, USBHIDConsumerControl, USBHIDGamepad, USBHIDKeyboard, USBHIDMouse, USBHIDSystemControl, or USBHIDVendor:

  1. Clone these nested repos somewhere:

git clone https://github.com/espressif/esp32-arduino-lib-builder.git esp32-arduino-lib-builder && \
git clone https://github.com/hathach/tinyusb.git esp32-arduino-lib-builder/components/arduino_tinyusb/tinyusb

  1. In the project folder, edit CMakeLists.txt and add the following before the project() line:

set(EXTRA_COMPONENT_DIRS <path to esp32-arduino-lib-builder/components/arduino_tinyusb>)

Configuration

Depending on one of the two following options, in the menuconfig set the appropriate settings.

Go to the section Arduino Configuration --->

  1. For usage of app_main() function - Turn off Autostart Arduino setup and loop on boot

  2. For usage of setup() and loop() functions - Turn on Autostart Arduino setup and loop on boot

Experienced users can explore other options in the Arduino section.

After the setup you can save and exit:

  • Save [S]

  • Confirm default filename [Enter]

  • Close confirmation window [Enter] or [Space] or [Esc]

  • Quit [Q]

Option 1. Using Arduino setup() and loop()

  • In main folder rename file main.c to main.cpp.

  • In main folder open file CMakeList.txt and change main.c to main.cpp as described below.

  • Your main.cpp should be formatted like any other sketch.

//file: main.cpp
#include "Arduino.h"

void setup(){
  Serial.begin(115200);
  while(!Serial){
    ; // wait for serial port to connect
  }
}

void loop(){
    Serial.println("loop");
    delay(1000);
}

Option 2. Using ESP-IDF appmain()

In main.c or main.cpp you need to implement app_main() and call initArduino(); in it.

Keep in mind that setup() and loop() will not be called in this case. Furthermore the app_main() is single execution as a normal function so if you need an infinite loop as in Arduino place it there.

//file: main.c or main.cpp
#include "Arduino.h"

extern "C" void app_main()
{
  initArduino();

  // Arduino-like setup()
  Serial.begin(115200);
  while(!Serial){
    ; // wait for serial port to connect
  }

  // Arduino-like loop()
  while(true){
    Serial.println("loop");
  }

  // WARNING: if program reaches end of function app_main() the MCU will restart.
}

Build, flash and monitor

  • For both options use command idf.py -p <your-board-serial-port> flash monitor

  • The project will build, upload and open the serial monitor to your board

    • Some boards require button combo press on the board: press-and-hold Boot button + press-and-release RST button, release Boot button

    • After a successful flash, you may need to press the RST button again

    • To terminate the serial monitor press [Ctrl] + [ ] ]

Logging To Serial

If you are writing code that does not require Arduino to compile and you want your ESP_LOGx macros to work in Arduino IDE, you can enable the compatibility by adding the following lines:

#ifdef ARDUINO_ARCH_ESP32
#include "esp32-hal-log.h"
#endif

FreeRTOS Tick Rate (Hz)

The Arduino component requires the FreeRTOS tick rate CONFIG_FREERTOS_HZ set to 1000Hz in make menuconfig -> Component config -> FreeRTOS -> Tick rate.

Compilation Errors

As commits are made to esp-idf and submodules, the codebases can develop incompatibilities that cause compilation errors. If you have problems compiling, follow the instructions in Issue #1142 to roll esp-idf back to a different version.

Adding arduino library

There are few approaches:

  1. Add global library to components/arduino-esp32/libraries/new_library

  2. Add local project library to examples/your_project/main/libraries/new_library

1 Adding global library

Download the library:

cd ~/esp/esp-idf/components/arduino-esp32/
git clone --recursive [email protected]:Author/new_library.git libraries/new_library

Edit file components/arduino-esp32/CMakeLists.txt

Get the source file list with shell command:

find libraries/new_library/src/ -name '*.c' -o -name '*.cpp'
  libraries/new_library/src/new_library.cpp
  libraries/new_library/src/new_library_extra_file.c

Locate block which starts with set(LIBRARY_SRCS and copy the list there. Now it should look something like this:

set(LIBRARY_SRCS
  libraries/ArduinoOTA/src/ArduinoOTA.cpp
  libraries/AsyncUDP/src/AsyncUDP.cpp
  libraries/new_library/src/new_library.cpp
  libraries/new_library/src/new_library_extra_file.c

After this add the library path to block which starts with set(includedirs. It should look like this:

set(includedirs
  variants/${CONFIG_ARDUINO_VARIANT}/
  cores/esp32/
  libraries/ArduinoOTA/src
  libraries/AsyncUDP/src
  libraries/new_library/src

2 Adding local library

Download the library:

cd ~/esp/esp-idf/examples/your_project
mkdir components
git clone --recursive [email protected]:Author/new_library.git components/new_library

Create new CMakeists.txt in the library folder: components/new_library/CMakeLists.txt

idf_component_register(SRCS "new_library.cpp" "another_source.c"
                      INCLUDE_DIRS "."
                      REQUIRES arduino-esp32
                      )

You can read more about CMakeLists in the IDF documentation regarding the Build System

Tip

If you want to use arduino-esp32 both as an ESP-IDF component and with Arduino IDE you can simply create a symlink:

ln -s ~/Arduino/hardware/espressif/esp32  ~/esp/esp-idf/components/arduino-esp32

This will allow you to install new libraries as usual with Arduino IDE. To use them with IDF component, use add_lib.sh -e ~/Arduino/libraries/New_lib