Getting started with the Espressif ESP32-DevKitC and the ESP-WROVER-KIT - FreeRTOS
OverviewPrerequisitesGet started with ESP-IDF v3.3Get started with the ESP-IDF v4.2Monitoring MQTT messages on the cloudRun the Bluetooth Low Energy demosUsing FreeRTOS in your own CMake project for ESP32TroubleshootingDebugging

Getting started with the Espressif ESP32-DevKitC and the ESP-WROVER-KIT

Follow this tutorial to get started with the Espressif ESP32-DevKitC equipped with ESP32-WROOM-32, ESP32-SOLO-1, or ESP-WROVER modules and the ESP-WROVER-KIT-VB. To purchase one from our partner on the AWS Partner Device catalog, use the following links:

These versions of development boards are supported on FreeRTOS.

For more information about the latest versions of these boards, see ESP32-DevKitC V4 or ESP-WROVER-KIT v4.1 on the Espressif website.

Note

Currently, the FreeRTOS port for ESP32-WROVER-KIT and ESP DevKitC doesn't support the Symmetric multiprocessing (SMP) feature.

Overview

This tutorial guides you through the following steps:

  1. Connecting your board to a host machine

  2. Installing software on the host machine for developing and debugging embedded applications for your microcontroller board

  3. Cross compiling a FreeRTOS demo application to a binary image

  4. Loading the application binary image to your board, and then running the application

  5. Interacting with the application running on your board across a serial connection, for monitoring and debugging purposes

Prerequisites

Before you get started with FreeRTOS on your Espressif board, you must set up your AWS account and permissions.

To create an account, see Create and Activate an AWS Account.

To add an AWS Identity and Access Management (IAM) user to your account, see the IAM User Guide. To grant your IAM user account access to AWS IoT and FreeRTOS, attach the following IAM policies to your IAM user account:

  • AmazonFreeRTOSFullAccess

    Allows full access to all of your IAM user's FreeRTOS resources (freertos:*).

  • AWSIoTFullAccess

    Allows full access to all of your IAM user's AWS IoT resources (iot:*).

To attach the AmazonFreeRTOSFullAccess policy to your IAM user

  1. Navigate to the IAM console.

  2. In the navigation pane, choose Users.

  3. Enter your user name in the search text box, and then choose it from the list.

  4. Choose Add permissions.

  5. Choose Attach existing policies directly.

  6. In the search box, enter AmazonFreeRTOSFullAccess, choose it from the list, and then choose Next: Review.

  7. Choose Add permissions.

To attach the AWSIoTFullAccess policy to your IAM user

  1. Navigate to the IAM console.

  2. In the navigation pane, choose Users.

  3. Enter your user name in the search text box, and then choose it from the list.

  4. Choose Add permissions.

  5. Choose Attach existing policies directly.

  6. In the search box, enter AWSIoTFullAccess, choose it from the list, and then choose Next: Review.

  7. Choose Add permissions.

For more information about IAM and user accounts, see the IAM User Guide.

For more information about policies, see Permissions and policies in IAM.

Note

The FreeRTOS 202012.00 release supports ESP-IDF v3.3. If you're using a later version of FreeRTOS, follow the instructions specific to IDFv4.2 at Get started with the ESP-IDF v4.2.

Get started with ESP-IDF v3.3

This section shows you how to use ESP-IDF v3.3 on Espressif hardware. To use ESP-IDF v4.2, see Get started with the ESP-IDF v4.2.

Set up the Espressif hardware

For more information about setting up the ESP32-DevKitC development board hardware, see the ESP32-DevKitC V4 Getting Started Guide.

For information about setting up the ESP-WROVER-KIT development board hardware. see the ESP-WROVER-KIT V4.1 Getting Started Guide.

Important

When you reach the Get Started section of the Espressif guides, stop, and then follow the steps below.

Set up your development environment

To communicate with your board, you must download and install a toolchain.

Setting up the toolchain

Note

ESP-IDF v3.3 doesn't support the latest version of the ESP32 compiler. If you have already installed the latest version of the ESP32 compiler, you should uninstall it and use the compatible version of the compiler that is included in the toolchain installation. See the links in this section. To check the version of your compiler, run the following command. 

xtensa-esp32-elf-gcc --version

To set up the toolchain, follow these instructions for your host machine's operating system:

Important

When you reach the "Get ESP-IDF" instructions under Next Steps, stop, and then return to the instructions on this page.

If you followed the "Get ESP-IDF" instructions under Next Steps, just now or on a previous occasion, you should clear the IDF_PATH environment variable from your system before you continue. This environment variable was automatically set if you followed the "Get ESP-IDF" instructions.

Install CMake

The CMake build system is required to build the FreeRTOS demo and test applications for this device. FreeRTOS supports versions 3.13 and later.

You can download the latest version of CMake from CMake.org. Both source and binary distributions are available.

For more details about using CMake with FreeRTOS, see Using CMake with FreeRTOS.

Establish a serial connection

To establish a serial connection between your host machine and the ESP32-DevKitC, you must install CP210x USB to UART Bridge VCP drivers. You can download these drivers from Silicon Labs.

To establish a serial connection between your host machine and the ESP32-WROVER-KIT, you must install some FTDI virtual COM port drivers. You can download these drivers from FTDI.

For more information, see Establish Serial Connection with ESP32. After you establish a serial connection, make a note of the serial port for your board's connection. You need it when you build the demo.

Download and configure FreeRTOS

After you set up your environment, you can download FreeRTOS from GitHub, or from the FreeRTOS console.For instructions, see the README.md file on the GitHub website.

Configure the FreeRTOS demo applications

  1. If you're running macOS or Linux, open a terminal prompt. If you're running Windows, open the mingw32.exe. MinGW is a minimalist development environment for native Microsoft Windows applications.

  2. To verify that you have Python 2.7.10 or later installed, run 

    python --version

    The version installed is displayed. If you don't have Python 2.7.10 or later installed, you can install it from the Python website.

  3. You need the AWS Command Line Interface (AWS CLI) to run AWS IoT commands. If you're running Windows, use the easy_install awscli to install the AWS CLI in the mingw32 environment.

    If you're running macOS or Linux, see Installing the AWS CLI.

  4. Run aws configure and configure the AWS CLI with your AWS access key ID, secret access key, and AWS Region. For more information, see Configuring the AWS CLI.

  5. Use the following command to install the AWS SDK for Python (boto3):

    • On Windows, in the mingw32 environment, run 

      easy_install boto3

    • On macOS or Linux, run 

      pip install tornado nose --user

      and then run 

      pip install boto3 --user

FreeRTOS includes the SetupAWS.py script to make it easier to set up your Espressif board to connect to AWS IoT. To configure the script, open freertos/tools/aws_config_quick_start/configure.json and set the following attributes:

afr_source_dir

The complete path to the freertos directory on your computer. Make sure that you use forward slashes to specify this path.

thing_name

The name that you want to assign to the AWS IoT thing that represents your board.

wifi_ssid

The SSID of your Wi-Fi network.

wifi_password

The password for your Wi-Fi network.

wifi_security

The security type for your Wi-Fi network.

The following are valid security types:

  • eWiFiSecurityOpen (Open, no security)

  • eWiFiSecurityWEP (WEP security)

  • eWiFiSecurityWPA (WPA security)

  • eWiFiSecurityWPA2 (WPA2 security)

To run the configuration script

  1. If you're running macOS or Linux, open a terminal prompt. If you're running Windows, open mingw32.exe.

  2. Navigate to the freertos/tools/aws_config_quick_start directory and run 

    python SetupAWS.py setup

The script does the following:

  • Creates an IoT thing, certificate, and policy

  • Attaches the IoT policy to the certificate and the certificate to the AWS IoT thing

  • Populates the aws_clientcredential.h file with your AWS IoT endpoint, Wi-Fi SSID, and credentials

  • Formats your certificate and private key and writes them to the aws_clientcredential_keys.h header file

    Note

    The certificate is hardcoded for demonstration purposes only. Production-level applications should store these files in a secure location.

For more information about SetupAWS.py, see the README.md in the freertos/tools/aws_config_quick_start directory.

Build, flash, and run the FreeRTOS demo project

You can use CMake to generate the build files, Make to build the application binary, and Espressif's IDF utility to flash your board.

Build FreeRTOS on Linux and MacOS (ESP-IDF v3.3)

If you're using Windows, see Build FreeRTOS on Windows (ESP-IDF v3.3).

Use CMake to generate the build files, and then use Make to build the application.

To generate the demo application's build files with CMake

  1. Change directories to the root of your FreeRTOS download directory.

  2. Use the following command to generate the build files.

    
cmake -DVENDOR=espressif -DBOARD=esp32_wrover_kit -DCOMPILER=xtensa-esp32 -S . -B your-build-directory
    Note

    If you want to build the application for debugging, add the -DCMAKE_BUILD_TYPE=Debug flag to this command.

    If you want to generate the test application build files, add the -DAFR_ENABLE_TESTS=1 flag.

    The code provided by Espressif uses the lightweight IP (lwIP) stack as the default networking stack. To use the FreeRTOS+TCP networking stack instead, add the –DAFR_ESP_FREERTOS_TCP flag to the CMake command.

    To add the lwIP dependency for non-vendor provided code, add the following lines to the CMake dependency file, CMakeLists.txt, for your custom Wi-Fi component. 

    
# Add a dependency on the bluetooth espressif component to the common component
set(COMPONENT_REQUIRES lwip)

To build the application with make

  1. Change directories to the build directory.

  2. Use the following command to build the application with Make.

    make all -j4
    Note

    You must generate the build files with the cmake command every time you switch between the aws_demos project and the aws_tests project.

Build FreeRTOS on Windows (ESP-IDF v3.3)

On Windows, you must specify a build generator for CMake. Otherwise, CMake defaults to Visual Studio. Espressif officially recommends the Ninja build system because it works on Windows, Linux and MacOS. You must run CMake commands in a native Windows environment like cmd or PowerShell. Running CMake commands in a virtual Linux environment, like MSYS2 or WSL, is not supported.

Use CMake to generate the build files, and then use Make to build the application.

To generate the demo application's build files with CMake

  1. Change directories to the root of your FreeRTOS download directory.

  2. Use the following command to generate the build files.

    
cmake -DVENDOR=espressif -DBOARD=esp32_wrover_kit -DCOMPILER=xtensa-esp32 -GNinja -S . -B build-directory
    Note

    If you want to build the application for debugging, add the -DCMAKE_BUILD_TYPE=Debug flag to this command.

    If you want to generate the test application build files, add the -DAFR_ENABLE_TESTS=1 flag.

    The code provided by Espressif uses the lightweight IP (lwIP) stack as the default networking stack. To use the FreeRTOS+TCP networking stack instead, add the –DAFR_ESP_FREERTOS_TCP flag to the CMake command.

    To add the lwIP dependency for non-vendor provided code, add the following lines to the CMake dependency file, CMakeLists.txt, for your custom Wi-Fi component. 

    
# Add a dependency on the bluetooth espressif component to the common component
set(COMPONENT_REQUIRES lwip)

To build the application

  1. Change directories to the build directory.

  2. Invoke Ninja to build the application.

    ninja

    Or, use the generic CMake interface to build the application.

    cmake --build build-directory
    Note

    You must generate the build files with the cmake command every time you switch between the aws_demos project and the aws_tests project.

Flash and run FreeRTOS (ESP-IDF v3.3)

This section shows you how to use ESP-IDF v3.3 on Espressif hardware. To use ESP-IDF v4.2, see Get started with the ESP-IDF v4.2.

Use Espressif's IDF utility (freertos/vendors/espressif/esp-idf/tools/idf.py) to flash your board, run the application, and see logs.

To erase the board's flash, go to the freertos directory and use the following command. 


./vendors/espressif/esp-idf/tools/idf.py erase_flash -B build-directory

To flash the application binary to your board, use make

make flash

You can also use the IDF script to flash your board:


./vendors/espressif/esp-idf/tools/idf.py flash -B build-directory

To monitor:


./vendors/espressif/esp-idf/tools/idf.py monitor -p /dev/ttyUSB1 -B build-directory
Note

You can combine these commands. For example:


./vendors/espressif/esp-idf/tools/idf.py erase_flash flash monitor -p /dev/ttyUSB1 -B build-directory

Get started with the ESP-IDF v4.2

This section shows you how to use ESP-IDF v4.2 on Espressif hardware. To use ESP-IDF v3.3, see Get started with ESP-IDF v3.3.

Set up the Espressif hardware

For information about setting up the ESP32-DevKitC development board hardware, see the ESP32-DevKitC V4 Getting Started Guide.

For information about setting up the ESP-WROVER-KIT development board hardware, see the ESP-WROVER-KIT V4.1 Getting Started Guide.

Important

When you reach the Get Started section of the Espressif guides, stop, and then return to the instructions on this page.

Set up your development environment

To communicate with your board, you must download and install a toolchain.

Setting up the toolchain

To set up the toolchain, follow these instructions for your host machine's operating system:

Important

When you reach the "Get ESP-IDF" instructions under Next Steps, stop, and then return to the instructions on this page.

Complete the installation (Linux / MacOS)

The ESP-IDF Windows installer installs all of the neceesary tools. The Linux and MacOS platforms require an additional step to complete the installation.

  1. Open a command line window

  2. Navigate to the FreeRTOS download directory, and then run the following script to download and install the espressif toolchain for your platform. 

    vendors/espressif/esp-idf/install.sh

  3. Add the ESP-IDF toolchain tools to your terminal's path with the following command.

    source vendors/espressif/esp-idf/export.sh

Establish a serial connection

To establish a serial connection between your host machine and the ESP32-DevKitC, you must install the CP210x USB to UART Bridge VCP drivers. You can download these drivers from Silicon Labs.

To establish a serial connection between your host machine and the ESP32-WROVER-KIT, you must install the FTDI virtual COM port driver. You can download this driver from FTDI.

For more information, see Establish Serial Connection with ESP32. After you establish a serial connection, make a note of the serial port for your board's connection. You need it when you build the demo.

Download and configure FreeRTOS

After you set up your environment, you can download FreeRTOS from GitHub, or from the FreeRTOS console. For instructions, see the README.md file on the GitHub website.

Configure the FreeRTOS demo applications

  1. If you're running macOS or Linux, open a terminal prompt. If you're running Windows, open mingw32.exe. ( MinGW is a minimalist development environment for native Microsoft Windows applications.)

  2. To verify that you have Python3 installed, run 

    python --version

    The version installed is displayed. If you don't have Python 3.0.1 or later installed, you can install it from the Python website.

  3. You need the AWS Command Line Interface (AWS CLI) to run AWS IoT commands. If you're running Windows, use the easy_install awscli to install the AWS CLI in the mingw32 environment.

    If you're running macOS or Linux, see Installing the AWS CLI.

  4. Run 

    aws configure

    and configure the AWS CLI with your AWS access key ID, secret access key, and default AWS Region. For more information, see Configuring the AWS CLI.

  5. Use the following command to install the AWS SDK for Python (boto3):

    • On Windows, in the mingw32 environment, run 

      easy_install boto3

    • On macOS or Linux, run 

      pip install tornado nose --user

      and then run 

      pip install boto3 --user

FreeRTOS includes the SetupAWS.py script to make it easier to set up your Espressif board to connect to AWS IoT. To configure the script, open freertos/tools/aws_config_quick_start/configure.json and set the following attributes:

afr_source_dir

The complete path to the freertos directory on your computer. Make sure that you use forward slashes to specify this path.

thing_name

The name that you want to assign to the AWS IoT thing that represents your board.

wifi_ssid

The SSID of your Wi-Fi network.

wifi_password

The password for your Wi-Fi network.

wifi_security

The security type for your Wi-Fi network.

The following are valid security types:

  • eWiFiSecurityOpen (Open, no security)

  • eWiFiSecurityWEP (WEP security)

  • eWiFiSecurityWPA (WPA security)

  • eWiFiSecurityWPA2 (WPA2 security)

To run the configuration script

  1. If you're running macOS or Linux, open a terminal prompt. If you're running Windows, open the mingw32.exe file.

  2. Navigate to the freertos/tools/aws_config_quick_start directory and run 

    python SetupAWS.py setup

The script does the following:

  • Creates an IoT thing, certificate, and policy

  • Attaches the IoT policy to the certificate and the certificate to the AWS IoT thing

  • Populates the aws_clientcredential.h file with your AWS IoT endpoint, Wi-Fi SSID, and credentials

  • Formats your certificate and private key and writes them to the aws_clientcredential_keys.h header file

    Note

    The certificate is hardcoded for demonstration purposes only. Production-level applications should store these files in a secure location.

For more information about SetupAWS.py, see the README.md in the freertos/tools/aws_config_quick_start directory.

Build, flash, and run the FreeRTOS demo project using the idy.py script

You can use Espressif's IDF utility to generate the build files, build the application binary, and flash your board.

Build and flash FreeRTOS on Windows, Linux, and MacOS (ESP-IDF v4.2)

Use the idf.py script to build the project and flash the binaries onto your device.

Note

Some setups might require that you use the port option "-p port-name" with idf.py to specify the correct port, as in the following example. 

idf.py -p /dev/cu.usbserial-00101301B flash

To build and flash the project

  1. Navigate to the root of your FreeRTOS download directory.

  2. In a command line window, enter the following command to add the ESP-IDF tools to your terminal's PATH.

    Windows

    vendors\espressif\esp-idf\export.bat

    Linux / MacOS

    source vendors/espressif/esp-idf/export.sh

  3. Configure cmake in the build directory and build the firmware image with the following command. 

    
idf.py -DVENDOR=espressif -DBOARD=esp32_wrover_kit -DCOMPILER=xtensa-esp32 build

    You should see output like the following.

    Running cmake in directory /path/to/hello_world/build
Executing "cmake -G Ninja --warn-uninitialized /path/to/hello_world"...
Warn about uninitialized values.
-- Found Git: /usr/bin/git (found version "2.17.0")
-- Building empty aws_iot component due to configuration
-- Component names: ...
-- Component paths: ...

... (more lines of build system output)

[527/527] Generating hello-world.bin
esptool.py v2.3.1

Project build complete. To flash, run this command:
../../../components/esptool_py/esptool/esptool.py -p (PORT) -b 921600 write_flash --flash_mode dio --flash_size detect --flash_freq 40m 0x10000 build/hello-world.bin  build 0x1000 build/bootloader/bootloader.bin 0x8000 build/partition_table/partition-table.bin
or run 'idf.py -p PORT flash'

    If there are no errors, the build will generate the firmware binary .bin files.

  4. Erase your development board's flash memory with the following command.

    idf.py erase_flash

  5. Use the idf.py script to flash the application binary to your board. 

    idf.py flash

  6. Monitor the output from your board's serial port with the following command.

    idf.py monitor
Note

You can combine these commands such as in the following example.

idf.py erase_flash flash monitor
Note

For certain host machine setups, you must specify the port when you flash the board such as in the following example. 


idf.py erase_flash flash monitor -p /dev/ttyUSB1

Build and Flash FreeRTOS with CMake

In addition to the idf.py script provided by the IDF SDK to build and run your code, you can also build the project with CMake. Currently, it supports either Unix Makefiles or the Ninja build system.

To build and flash the project

  1. In a command line window, navigate to the root of your FreeRTOS download directory.

  2. Run the following script to add the ESP-IDF tools to your shell's PATH.

    Windows

    vendors\espressif\esp-idf\export.bat

    Linux / MacOS

    source vendors/espressif/esp-idf/export.sh

  3. Enter the following command to generate the build files.

    With Unix Makefiles

    
cmake -DVENDOR=espressif -DBOARD=esp32_wrover_kit -DCOMPILER=xtensa-esp32 -S . -B ./YOUR_BUILD_DIRECTORY -DAFR_ENABLE_ALL_MODULES=1 -DAFR_ENABLE_TESTS=0

    With Ninja

    
cmake -DVENDOR=espressif -DBOARD=esp32_wrover_kit -DCOMPILER=xtensa-esp32 -S . -B ./YOUR_BUILD_DIRECTORY -DAFR_ENABLE_ALL_MODULES=1 -DAFR_ENABLE_TESTS=0 -GNinja

  4. Erase the flash and then flash the board.

    With Unix Makefiles

    make -C ./YOUR_BUILD_DIRECTORY erase_flash
    make -C ./YOUR_BUILD_DIRECTORY flash

    With Ninja

    ninja -C ./YOUR_BUILD_DIRECTORY erase_flash
    ninja -C ./YOUR_BUILD_DIRECTORY flash

Monitoring MQTT messages on the cloud

You can use the MQTT client in the AWS IoT console to monitor the messages that your device sends to the AWS Cloud.

To subscribe to the MQTT topic with the AWS IoT MQTT client

  1. Navigate to the AWS IoT console.

  2. In the navigation pane, choose Test to open the MQTT client.

  3. In Subscription topic, enter your-thing-name/example/topic, and then choose Subscribe to topic.

Run the Bluetooth Low Energy demos

FreeRTOS supports Bluetooth Low Energy connectivity.

To run the FreeRTOS demo project across Bluetooth Low Energy, you must run the FreeRTOS Bluetooth Low Energy Mobile SDK Demo Application on an iOS or Android mobile device.

To set up the FreeRTOS Bluetooth Low Energy mobile SDK demo application

  1. Follow the instructions in Mobile SDKs for FreeRTOS Bluetooth Devices to download and install the SDK for your mobile platform on your host computer.

  2. Follow the instructions in FreeRTOS Bluetooth Low Energy Mobile SDK Demo Application to set up the demo mobile application on your mobile device.

For instructions about how to run the MQTT over Bluetooth Low Energy demo on your board, see the MQTT over Bluetooth Low Energy Demo Application.

For instructions about how to run the Wi-Fi provisioning demo on your board, see the Wi-Fi Provisioning Demo Application.

Using FreeRTOS in your own CMake project for ESP32

If you want to consume FreeRTOS in your own CMake project, you can set it up as a subdirectory and build it together with your application. First, get a copy of FreeRTOS either from GitHub or from the FreeRTOS console. If you're using Git, you can also set it up as a Git submodule with the following command so it's easier to update in the future. 

git submodule add -b release https://github.com/aws/amazon-freertos.git freertos

If a later version is released, you can update your local copy with these commands.

# Pull the latest changes from the remote tracking branch.
git submodule update --remote -- amazon-freertos
# Commit the submodule change because it is pointing to a different revision now.
git add amazon-freertos
git commit -m "Update FreeRTOS to a new release"

If your project has the following directory structure:

- freertos (the copy that you obtained from GitHub or the AWS IoT console)
- src
  - main.c (your application code)
- CMakeLists.txt

Then the following is an example of the top-level CMakeLists.txt file that can be used to build your application together with FreeRTOS. 

cmake_minimum_required(VERSION 3.13)

project(freertos_examples)

add_executable(my_app src/main.c)

# Tell IDF build to link against this target.
set(IDF_PROJECT_EXECUTABLE my_app)

# Add FreeRTOS as a subdirectory. AFR_BOARD tells which board to target.
set(AFR_BOARD espressif.esp32_devkitc CACHE INTERNAL "")
add_subdirectory(freertos)

# Link against the mqtt library so that we can use it. Dependencies are transitively
# linked.
target_link_libraries(my_app PRIVATE AFR::mqtt)

To build the project, run the following CMake commands. Make sure the ESP32 compiler is in the PATH environment variable. 


cmake -S . -B build-directory -DCMAKE_TOOLCHAIN_FILE=freertos/tools/cmake/toolchains/xtensa-esp32.cmake -GNinja
cmake --build build

To flash the application to your board, run the following command.

cmake --build build-directory --target flash

Using components from FreeRTOS

After running CMake, you can find all available components in the summary output. It should look something like the following example. 

====================Configuration for FreeRTOS====================
  Version:                 201910.00
  Git version:             201910.00-388-gcb3612cb7

Target microcontroller:
  vendor:                  Espressif
  board:                   ESP32-DevKitC
  description:             Development board produced by Espressif that comes in two
                           variants either with ESP-WROOM-32 or ESP32-WROVER module
  family:                  ESP32
  data ram size:           520KB
  program memory size:     4MB

Host platform:
  OS:                      Linux-4.15.0-66-generic
  Toolchain:               xtensa-esp32
  Toolchain path:          /opt/xtensa-esp32-elf
  CMake generator:         Ninja

FreeRTOS modules:
  Modules to build:        ble, ble_hal, ble_wifi_provisioning, common, crypto, defender,
                           dev_mode_key_provisioning, freertos_plus_tcp, greengrass,
                           https, kernel, mqtt, ota, pkcs11, pkcs11_implementation,
                           platform, secure_sockets, serializer, shadow, tls, wifi
  Enabled by user:         ble, ble_hal, ble_wifi_provisioning, defender, greengrass,
                           https, mqtt, ota, pkcs11, pkcs11_implementation, platform,
                           secure_sockets, shadow, wifi
  Enabled by dependency:   common, crypto, demo_base, dev_mode_key_provisioning,
                           freertos, freertos_plus_tcp, kernel, pkcs11_mbedtls,
                           secure_sockets_freertos_plus_tcp, serializer, tls, utils
  3rdparty dependencies:   http_parser, jsmn, mbedtls, pkcs11, tinycbor
  Available demos:         demo_ble, demo_ble_numeric_comparison, demo_defender,
                           demo_greengrass_connectivity, demo_https, demo_mqtt, demo_ota,
                           demo_shadow, demo_tcp, demo_wifi_provisioning
  Available tests:
=========================================================================

You can reference any components from the Modules to build list. To link them into your application, put the AFR:: namespace in front of the name, for example, AFR::mqtt, AFR::ota, and so on.

Add custom components to ESP-IDF

You can add more components to the ESP-IDF build environment. For example, assuming you want to add a component called example_component, and your project looks like this 

- freertos
- components
  - example_component
    - include
      - example_component.h
    - src
      - example_component.c
    - CMakeLists.txt
- src
  - main.c
- CMakeLists.txt

then the following is an example of the CMakeLists.txt file for your component. 

# include paths of this components.
set(COMPONENT_ADD_INCLUDEDIRS include)

# source files of this components.
set(COMPONENT_SRCDIRS src)
# Alternatively, use COMPONENT_SRCS to specify source files explicitly
# set(COMPONENT_SRCS src/example_component.c)

# add this components, this will define a CMake library target.
register_component()

You can also specify dependencies using the standard CMake function target_link_libraries. Note that the target name for your component is stored in the variable COMPONENT_TARGET, defined by the ESP-IDF. 

# add this component, this will define a CMake library target.
register_component()

# standard CMake function can be used to specify dependencies. ${COMPONENT_TARGET} is defined
# from esp-idf when you call register_component, by default it's idf_component_<folder_name>.
target_link_libraries(${COMPONENT_TARGET} PRIVATE AFR::mqtt)

For ESP components, this is done by setting two variables COMPONENT_REQUIRES and COMPONENT_PRIV_REQUIRES. See Build System (CMake) in the ESP-IDF Programming Guide v4.2. 

# If the dependencies are from ESP-IDF, use these 2 variables. Note these need to be
# set before calling register_component().
set(COMPONENT_REQUIRES log)
set(COMPONENT_PRIV_REQUIRES lwip)

Then, in the top level CMakeLists.txt file, you tell ESP-IDF where to find these components. Add the following lines anywhere before add_subdirectory(freertos). 

# Add some extra components. IDF_EXTRA_COMPONENT_DIRS is a variable used by ESP-IDF
# to collect extra components.
get_filename_component(
    EXTRA_COMPONENT_DIRS
    "components/example_component" ABSOLUTE
)
list(APPEND IDF_EXTRA_COMPONENT_DIRS ${EXTRA_COMPONENT_DIRS})

This component is now automatically linked to your application code by default. You should be able to include its header files and call the functions it defines.

Override the configurations for FreeRTOS

There's currently no well-defined approach to redefining the configs outside of the FreeRTOS source tree. By default, CMake will look for the freertos/vendors/espressif/boards/esp32/aws_demos/config_files/ and freertos/demos/include/ directories. However, you can use a workaround to tell the compiler to search other directories first. For example, you can add another folder for FreeRTOS configurations. 

- freertos
- freertos-configs
  - aws_clientcredential.h
  - aws_clientcredential_keys.h
  - iot_mqtt_agent_config.h
  - iot_config.h
- components
- src
- CMakeLists.txt

The files under freertos-configs are copied from the freertos/vendors/espressif/boards/esp32/aws_demos/config_files/ and freertos/demos/include/ directories. Then, in your top level CMakeLists.txt file, add this line before add_subdirectory(freertos) so that the compiler will search this directory first. 

include_directories(BEFORE freertos-configs)

Providing your own sdkconfig for ESP-IDF

In case you want to provide your own sdkconfig.default, you can set the CMake variable IDF_SDKCONFIG_DEFAULTS, from the command line: 


cmake -S . -B build-directory -DIDF_SDKCONFIG_DEFAULTS=path_to_your_sdkconfig_defaults -DCMAKE_TOOLCHAIN_FILE=freertos/tools/cmake/toolchains/xtensa-esp32.cmake -GNinja

If you don’t specify a location for your own sdkconfig.default file, FreeRTOS will use the default file located at freertos/vendors/espressif/boards/esp32/aws_demos/sdkconfig.defaults.

Summary

If you have a project with a component called example_component, and you want to override some configurations, here's a complete example of the top level CMakeLists.txt file. 

cmake_minimum_required(VERSION 3.13)

project(freertos_examples)

add_executable(my_app src/main.c)

# Tell IDF build to link against this target.
set(IDF_PROJECT_EXECUTABLE my_app)

# Add some extra components. IDF_EXTRA_COMPONENT_DIRS is a variable used by ESP-IDF
# to collect extra components.
get_filename_component(
    EXTRA_COMPONENT_DIRS
    "components/example_component" ABSOLUTE
)
list(APPEND IDF_EXTRA_COMPONENT_DIRS ${EXTRA_COMPONENT_DIRS})

# Override the configurations for FreeRTOS.
include_directories(BEFORE freertos-configs)

# Add FreeRTOS as a subdirectory. AFR_BOARD tells which board to target.
set(AFR_BOARD espressif.esp32_devkitc CACHE INTERNAL "")
add_subdirectory(freertos)

# Link against the mqtt library so that we can use it. Dependencies are transitively
# linked.
target_link_libraries(my_app PRIVATE AFR::mqtt)

Troubleshooting

  • If you're running macOS and the operating system doesn't recognize your ESP-WROVER-KIT, make sure you don't have the D2XX drivers installed. To uninstall them, follow the instructions in the FTDI Drivers Installation Guide for macOS X.

  • The monitor utility provided by ESP-IDF (and invoked using make monitor) helps you decode addresses. For this reason, it can help you get some meaningful backtraces in the event the application stops working. For more information, see Automatic Address Decoding on the Espressif website.

  • It's also possible to enable GDBstub for communication with gdb without requiring any special JTAG hardware. For more information, see Launching GDB with GDBStub on the Espressif website.

  • For information about setting up an OpenOCD-based environment if JTAG hardware-based debugging is required, see JTAG Debugging on the Espressif website.

  • If pyserial can't be installed using pip on macOS, download it from the pyserial website.

  • If the board resets continuously, try erasing the flash by entering the following command on the terminal. 

    make erase_flash

  • If you see errors when you run idf_monitor.py, use Python 2.7.

  • Required libraries from ESP-IDF are included in FreeRTOS, so there is no need to download them externally. If the IDF_PATH environment variable is set, we recommend that you clear it before you build FreeRTOS.

  • On Windows, it can take 3-4 minutes for the project to build. You can use the -j4 switch on the make command to reduce the build time: 

    make flash monitor -j4

  • If your device has trouble connecting to AWS IoT, open the aws_clientcredential.h file, and verify that the configuration variables are properly defined in the file. clientcredentialMQTT_BROKER_ENDPOINT[] should look like 1234567890123-ats.iot.us-east-1.amazonaws.com.

  • If you're following the steps in Using FreeRTOS in your own CMake project for ESP32 and you see undefined reference errors from the linker, it's usually because of missing dependent libraries or demos. To add them, update the CMakeLists.txt file (under the root directory) using the standard CMake function target_link_libraries.

  • ESP-IDF v4.2 supports the use of the xtensa-esp32-elf-gcc 8.2.0. toolchain. If you're using an earlier version of the Xtensa toolchain, download the required version.

  • If you see an error log like the following about python dependencies that are not being met for ESP-IDF v4.2. 

    The following Python requirements are not satisfied:
click>=5.0
pyserial>=3.0
future>=0.15.2
pyparsing>=2.0.3,<2.4.0
pyelftools>=0.22
gdbgui==0.13.2.0
pygdbmi<=0.9.0.2
reedsolo>=1.5.3,<=1.5.4
bitstring>=3.1.6
ecdsa>=0.16.0
Please follow the instructions found in the "Set up the tools" section of ESP-IDF Getting Started Guide

    Install the python dependencies on your platform using the following Python command:

    root/vendors/espressif/esp-idf/requirements.txt

For more troubleshooting information, see Troubleshooting getting started.

Debugging

Debugging code on Espressif ESP32-DevKitC and ESP-WROVER-KIT (ESP-IDF v3.3)

This section shows you how to debug Espressif hardware using ESP-IDF v3.3. To debug using ESP-IDF v4.2, see Debugging code on Espressif ESP32-DevKitC and ESP-WROVER-KIT (ESP-IDF v4.2).

You need a JTAG to USB cable. We use a USB to MPSSE cable (for example, the FTDI C232HM-DDHSL-0).

ESP-DevKitC JTAG setup

For the FTDI C232HM-DDHSL-0 cable, these are the connections to the ESP32 DevkitC.

C232HM-DDHSL-0 Wire Color ESP32 GPIO Pin JTAG Signal Name

Brown (pin 5)

IO14

TMS

Yellow (pin 3)

IO12

TDI

Black (pin 10)

GND

GND

Orange (pin 2)

IO13

TCK

Green (pin 4)

IO15

TDO

ESP-WROVER-KIT JTAG setup

For the FTDI C232HM-DDHSL-0 cable, these are the connections to the ESP32-WROVER-KIT.

C232HM-DDHSL-0 Wire Color ESP32 GPIO Pin JTAG Signal Name

Brown (pin 5)

IO14

TMS

Yellow (pin 3)

IO12

TDI

Orange (pin 2)

IO13

TCK

Green (pin 4)

IO15

TDO

These tables were developed from the FTDI C232HM-DDHSL-0 datasheet. For more information, see the section "C232HM MPSSE Cable Connection and Mechanical Details in the data sheet.

To enable JTAG on the ESP-WROVER-KIT, place jumpers on the TMS, TDO, TDI, TCK, and S_TDI pins as shown here.

Jumper placement

Debugging on Windows (ESP-IDF v3.3)

To set up for debugging on Windows

  1. Connect the USB side of the FTDI C232HM-DDHSL-0 to your computer and the other side as described in Debugging code on Espressif ESP32-DevKitC and ESP-WROVER-KIT (ESP-IDF v3.3). The FTDI C232HM-DDHSL-0 device should appear in Device Manager under Universal Serial Bus Controllers.

  2. Under the list of universal serial bus devices, right-click the C232HM-DDHSL-0 device, and choose Properties.

    Note

    The device might be listed as USB Serial Port.

    In the properties window, choose the Details tab to see the properties of the device. If the device isn't listed, install the Windows driver for FTDI C232HM-DDHSL-0.

  3. On the Details tab, choose Property, and then choose Hardware IDs. You should see something like this in the Value field. 

    FTDIBUS\COMPORT&VID_0403&PID_6014

    In this example, the vendor ID is 0403 and the product ID is 6014.

    Verify these IDs match the IDs in projects/espressif/esp32/make/aws_demos/esp32_devkitj_v1.cfg. The IDs are specified in a line that begins with ftdi_vid_pid followed by a vendor ID and a product ID. 

    ftdi_vid_pid 0x0403 0x6014

  4. Download OpenOCD for Windows.

  5. Unzip the file to C:\ and add C:\openocd-esp32\bin to your system path.

  6. OpenOCD requires libusb, which is not installed by default on Windows.

    To install libusb

    1. Download zadig.exe.

    2. Run zadig.exe. From the Options menu, choose List All Devices.

    3. From the drop-down menu, choose C232HM-DDHSL-0.

    4. In the target driver field, to the right of the green arrow, choose WinUSB.

    5. From the dropdown list under the target driver field, choose the arrow, and then choose Install Driver. Choose Replace Driver.

  7. Open a command prompt, navigate to projects/espressif/esp32/make/aws_demos and run the following command.

    For ESP32-WROOM-32 and ESP32-WROVER

    openocd.exe -f esp32_devkitj_v1.cfg -f esp-wroom-32.cfg

    For ESP32-SOLO-1

    openocd.exe -f esp32_devkitj_v1.cfg -f esp-solo-1.cfg

    Leave this command prompt open.

  8. Open a new command prompt, navigate to your msys32 directory, and run mingw32.exe.

  9. In the mingw32 terminal, navigate to projects/espressif/esp32/make/aws_demos and run 

    make flash monitor

  10. Open another mingw32 terminal, navigate to projects/espressif/esp32/make/aws_demos and wait until the demo starts running on your board. When it does, run xtensa-esp32-elf-gdb -x gdbinit build/aws_demos.elf. The program should stop in the main function.

Note

The ESP32 supports a maximum of two break points.

Debugging on macOS (ESP-IDF v3.3)

  1. Download the FTDI driver for macOS.

  2. Download OpenOCD.

  3. Extract the downloaded .tar file and set the path in .bash_profile to OCD_INSTALL_DIR/openocd-esp32/bin.

  4. Use the following command to install libusb on macOS. 

    brew install libusb

  5. Use the following command to unload the serial port driver.

    sudo kextunload -b com.FTDI.driver.FTDIUSBSerialDriver

  6. If you're running a macOS version later than 10.9, use the following command to unload the Apple FTDI driver. 

    sudo kextunload -b com.apple.driver.AppleUSBFTDI

  7. Use the following command to get the product ID and vendor ID of the FTDI cable. It lists the attached USB devices. 

    system_profiler SPUSBDataType

    The output from system_profiler should look like the following. 

    DEVICE:
                            
Product ID: product-ID
Vendor ID: vendor-ID (Future Technology Devices International Limited)

  8. Open the projects/espressif/esp32/make/aws_demos/esp32_devkitj_v1.cfg file. The vendor ID and product ID for your device are specified in a line that begins with ftdi_vid_pid. Change the IDs to match the IDs from the system_profiler output in the previous step.

  9. Open a terminal window, navigate to projects/espressif/esp32/make/aws_demos, and use the following command to run OpenOCD.

    For ESP32-WROOM-32 and ESP32-WROVER:

    openocd -f esp32_devkitj_v1.cfg -f esp-wroom-32.cfg

    For ESP32-SOLO-1:

    openocd -f esp32_devkitj_v1.cfg -f esp-solo-1.cfg

  10. Open a new terminal, and use the following command to load the FTDI serial port driver.

    sudo kextload -b com.FTDI.driver.FTDIUSBSerialDriver

  11. Navigate to projects/espressif/esp32/make/aws_demos, and run the following command. 

    make flash monitor

  12. Open another new terminal, navigate to projects/espressif/esp32/make/aws_demos, and run the following command. 

    xtensa-esp32-elf-gdb -x gdbinit build/aws_demos.elf

    The program should stop at main().

Debugging on Linux (ESP-IDF v3.3)

  1. Download OpenOCD. Extract the tarball and follow the installation instructions in the readme file.

  2. Use the following command to install libusb on Linux.

    sudo apt-get install libusb-1.0

  3. Open a terminal and enter ls -l /dev/ttyUSB* to list all USB devices connected to your computer. This helps you check if the board's USB ports are recognized by the operating system. You should see output like the following. 

    $ls -l /dev/ttyUSB*
crw-rw----    1    root    dialout    188,    0    Jul    10    19:04    /dev/ttyUSB0
crw-rw----    1    root    dialout    188,    1    Jul    10    19:04    /dev/ttyUSB1

  4. Sign off and then sign in and cycle the power to the board to make the changes take effect. In a terminal prompt, list the USB devices. Make sure the group owner has changed from dialout to plugdev. 

    $ls -l /dev/ttyUSB*
crw-rw----    1    root    plugdev    188,    0    Jul    10    19:04    /dev/ttyUSB0
crw-rw----    1    root    plugdev    188,    1    Jul    10    19:04    /dev/ttyUSB1

    The /dev/ttyUSBn interface with the lower number is used for JTAG communication. The other interface is routed to the ESP32's serial port (UART) and is used for uploading code to the ESP32’s flash memory.

  5. In a terminal window, navigate to projects/espressif/esp32/make/aws_demos, and use the following command to run OpenOCD.

    For ESP32-WROOM-32 and ESP32-WROVER:

    openocd -f esp32_devkitj_v1.cfg -f esp-wroom-32.cfg

    For ESP32-SOLO-1:

    openocd -f esp32_devkitj_v1.cfg -f esp-solo-1.cfg

  6. Open another terminal, navigate to projects/espressif/esp32/make/aws_demos, and run the following command. 

    make flash monitor

  7. Open another terminal, navigate to projects/espressif/esp32/make/aws_demos, and run the following command: 

    xtensa-esp32-elf-gdb -x gdbinit build/aws_demos.elf

    The program should stop in main().

Debugging code on Espressif ESP32-DevKitC and ESP-WROVER-KIT (ESP-IDF v4.2)

This section shows you how to debug Espressif hardware using ESP-IDF v4.2. To debug using ESP-IDF v3.3, see Debugging code on Espressif ESP32-DevKitC and ESP-WROVER-KIT (ESP-IDF v3.3).

You need a JTAG to USB cable. We use a USB to MPSSE cable (for example, the FTDI C232HM-DDHSL-0).

ESP-DevKitC JTAG setup

For the FTDI C232HM-DDHSL-0 cable, these are the connections to the ESP32 DevkitC.

C232HM-DDHSL-0 Wire Color ESP32 GPIO Pin JTAG Signal Name

Brown (pin 5)

IO14

TMS

Yellow (pin 3)

IO12

TDI

Black (pin 10)

GND

GND

Orange (pin 2)

IO13

TCK

Green (pin 4)

IO15

TDO

ESP-WROVER-KIT JTAG setup

For the FTDI C232HM-DDHSL-0 cable, these are the connections to the ESP32-WROVER-KIT.

C232HM-DDHSL-0 Wire Color ESP32 GPIO Pin JTAG Signal Name

Brown (pin 5)

IO14

TMS

Yellow (pin 3)

IO12

TDI

Orange (pin 2)

IO13

TCK

Green (pin 4)

IO15

TDO

These tables were developed from the FTDI C232HM-DDHSL-0 datasheet. For more information, see the section "C232HM MPSSE Cable Connection and Mechanical Details in the data sheet.

To enable JTAG on the ESP-WROVER-KIT, place jumpers on the TMS, TDO, TDI, TCK, and S_TDI pins as shown here.

Jumper placement

Debugging on Windows (ESP-IDF v4.2)

To set up for debugging on Windows

  1. Connect the USB side of the FTDI C232HM-DDHSL-0 to your computer and the other side as described in Debugging code on Espressif ESP32-DevKitC and ESP-WROVER-KIT (ESP-IDF v4.2). The FTDI C232HM-DDHSL-0 device should appear in Device Manager under Universal Serial Bus Controllers.

  2. Under the list of universal serial bus devices, right-click the C232HM-DDHSL-0 device, and choose Properties.

    Note

    The device might be listed as USB Serial Port.

    In the properties window, choose the Details tab to see the properties of the device. If the device isn't listed, install the Windows driver for FTDI C232HM-DDHSL-0.

  3. On the Details tab, choose Property, and then choose Hardware IDs. You should see something like this in the Value field. 

    FTDIBUS\COMPORT&VID_0403&PID_6014

    In this example, the vendor ID is 0403 and the product ID is 6014.

    Verify these IDs match the IDs in projects/espressif/esp32/make/aws_demos/esp32_devkitj_v1.cfg. The IDs are specified in a line that begins with ftdi_vid_pid followed by a vendor ID and a product ID. 

    ftdi_vid_pid 0x0403 0x6014

  4. Download OpenOCD for Windows.

  5. Unzip the file to C:\ and add C:\openocd-esp32\bin to your system path.

  6. OpenOCD requires libusb, which is not installed by default on Windows.

    To install libusb

    1. Download zadig.exe.

    2. Run zadig.exe. From the Options menu, choose List All Devices.

    3. From the drop-down menu, choose C232HM-DDHSL-0.

    4. In the target driver field, to the right of the green arrow, choose WinUSB.

    5. From the dropdown list under the target driver field, choose the arrow, and then choose Install Driver. Choose Replace Driver.

  7. Open a command prompt, navigate to the root of your FreeRTOS download directory, and run the following command. 

    idf.py openocd

    Leave this command prompt open.

  8. Open a new command prompt, navigate to the root of your FreeRTOS download directory, and run 

    idf.py flash monitor

  9. Open another command prompt, navigate to the root of your FreeRTOS download directory, and wait until the demo starts running on your board. When it does, run 

    idf.py gdb

    The program should stop in the main function.

Note

The ESP32 supports a maximum of two break points.

Debugging on macOS (ESP-IDF v4.2)

  1. Download the FTDI driver for macOS.

  2. Download OpenOCD.

  3. Extract the downloaded .tar file and set the path in .bash_profile to OCD_INSTALL_DIR/openocd-esp32/bin.

  4. Use the following command to install libusb on macOS. 

    brew install libusb

  5. Use the following command to unload the serial port driver.

    sudo kextunload -b com.FTDI.driver.FTDIUSBSerialDriver

  6. If you're running a macOS version later than 10.9, use the following command to unload the Apple FTDI driver. 

    sudo kextunload -b com.apple.driver.AppleUSBFTDI

  7. Use the following command to get the product ID and vendor ID of the FTDI cable. It lists the attached USB devices. 

    system_profiler SPUSBDataType

    The output from system_profiler should look like the following. 

    DEVICE:
                            
Product ID: product-ID
Vendor ID: vendor-ID (Future Technology Devices International Limited)

  8. Open the projects/espressif/esp32/make/aws_demos/esp32_devkitj_v1.cfg file. The vendor ID and product ID for your device are specified in a line that begins with ftdi_vid_pid. Change the IDs to match the IDs from the system_profiler output in the previous step.

  9. Open a terminal window, navigate to the root of your FreeRTOS download directory, and use the following command to run OpenOCD. 

    idf.py openocd

    Leave this terminal window open.

  10. Open a new terminal, and use the following command to load the FTDI serial port driver.

    sudo kextload -b com.FTDI.driver.FTDIUSBSerialDriver

  11. Navigate to the root of your FreeRTOS download directory, and run 

    idf.py flash monitor

  12. Open another new terminal, navigate to the root of your FreeRTOS download directory, and run 

    idf.py gdb

    The program should stop at main.

Debugging on Linux (ESP-IDF v4.2)

  1. Download OpenOCD. Extract the tarball and follow the installation instructions in the readme file.

  2. Use the following command to install libusb on Linux.

    sudo apt-get install libusb-1.0

  3. Open a terminal and enter ls -l /dev/ttyUSB* to list all USB devices connected to your computer. This helps you check if the board's USB ports are recognized by the operating system. You should see output like the following. 

    $ls -l /dev/ttyUSB*
crw-rw----    1    root    dialout    188,    0    Jul    10    19:04    /dev/ttyUSB0
crw-rw----    1    root    dialout    188,    1    Jul    10    19:04    /dev/ttyUSB1

  4. Sign off and then sign in and cycle the power to the board to make the changes take effect. In a terminal prompt, list the USB devices. Make sure the group owner has changed from dialout to plugdev. 

    $ls -l /dev/ttyUSB*
crw-rw----    1    root    plugdev    188,    0    Jul    10    19:04    /dev/ttyUSB0
crw-rw----    1    root    plugdev    188,    1    Jul    10    19:04    /dev/ttyUSB1

    The /dev/ttyUSBn interface with the lower number is used for JTAG communication. The other interface is routed to the ESP32's serial port (UART) and is used for uploading code to the ESP32’s flash memory.

  5. In a terminal window, navigate to the root of your FreeRTOS download directory, and use the following command to run OpenOCD. 

    idf.py openocd

  6. Open another terminal, navigate to the root of your FreeRTOS download directory, and run the following command. 

    idf.py flash monitor

  7. Open another terminal, navigate the root of your FreeRTOS download directory, and run the following command: 

    idf.py gdb

    The program should stop in main().