Amazon FreeRTOS
User Guide

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

If you don't have an Espressif ESP32-DevKitC, visit the AWS Partner Device Catalog to purchase one from our partner. If you don't have an Espressif ESP32-WROVER-KIT, visit the AWS Partner Device Catalog to purchase one from our partner. Both devices are supported on Amazon FreeRTOS. To check which development module you have, see ESP32 Modules and Boards.

Note

Currently, the Amazon FreeRTOS port for ESP32-WROVER-KIT and ESP DevKitC does not support the following:

  • Lightweight IP.

  • Symmetric multiprocessing (SMP).

Setting Up the Espressif Hardware

See the ESP32-DevKitC Getting Started Guide for information about setting up the ESP32-DevKitC development board hardware.

See the ESP-WROVER-KIT Getting Started Guide for information about setting up the ESP-WROVER-KIT development board hardware.

Note

Do not proceed to the Get Started section of the Espressif guides. Instead, follow the steps below.

Setting Up Your Environment

Establishing a Serial Connection

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

For more information about establishing a serial connection with Espressif boards, 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.

Setting Up the Toolchain

You need to set up the Espressif toolchain to communicate with your board. To set up the toolchain, following the instructions for your host machine's operating system:

Note

When following the toolchain setup instructions, do not proceed to the Get ESP-IDF instructions under Next Steps. Instead, continue following the instructions on this page.

Download and Configure Amazon FreeRTOS

After your environment is set up, you can download Amazon FreeRTOS from GitHub. Configurations of Amazon FreeRTOS for the Espressif boards are not available from the Amazon FreeRTOS console.

Downloading Amazon FreeRTOS

Clone the amazon-freertos repository from GitHub.

In this tutorial, the path to the amazon-freertos directory is referred to as BASE_FOLDER.

Note

The maximum length of a file path on Microsoft Windows is 260 characters. The longest path in the Amazon FreeRTOS download is 122 characters. To accommodate the files in the Amazon FreeRTOS projects, make sure that the path to the amazon-freertos directory is fewer than 98 characters long. For example, C:\Users\Username\Dev\amazon-freertos works, but C:\Users\Username\Documents\Development\Projects\amazon-freertos causes build failures.

Configure Your Project

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

  2. Install Python 2.7.10 or later.

  3. If you are running Windows, use the easy_install awscli to install the AWS CLI in the mingw32 environment.

    If you are running macOS or Linux, make sure the AWS CLI is installed on your system. For more information, see Installing the AWS Command Line Interface.

  4. Run aws configure and configure the AWS CLI with your AWS Access Key ID, Secret Access Key, and Default region name. For more information, see Configuring the AWS CLI.

  5. Use the following command to install the boto3 Python module:

    • On Windows, in the mingw32 environment, use easy_install boto3

    • On macOS or Linux, use pip install boto3

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

afr_source_dir

The complete path to the amazon-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.

Valid security types are:

  • eWiFiSecurityOpen (Open, no security)

  • eWiFiSecurityWEP (WEP security)

  • eWiFiSecurityWPA (WPA security)

  • eWiFiSecurityWPA2 (WPA2 security)

To run the configuration script

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

  2. Go to the <BASE_FOLDER>/tools/aws_config_quick_start directory and run the following command:

    python SetupAWS.py setup

This script creates an IoT thing, certificate, and policy. It attaches the IoT policy to the certificate and the certificate to the IoT thing. It also populates the aws_clientcredential.h file with your AWS IoT endpoint, Wi-Fi SSID, and credentials. Finally, it formats your certificate and private key and writes them to the aws_clientcredential.h header file. For more information about the script, see the README.md in the <BASE_FOLDER>/tools/aws_config_quick_start directory.

Build and Run the Amazon FreeRTOS Demo Project

To configure your board's connection for flashing the demo

  1. Connect your board to your host computer.

  2. If you are using macOS or Linux, open a terminal. If you are using Windows, open mingw32.exe (downloaded from mysys toolchain).

  3. Navigate to <BASE_FOLDER>/demos/espressif/esp32_devkitc_esp_wrover_kit/make and enter following command to make and open the Espressif IoT Development Framework Configuration menu:

    make menuconfig

    To confirm a selection in the menu, choose Select. To save a configuration, choose Save. To exit the menu, choose Exit.

  4. In the Espressif IoT Development Framework Configuration menu, navigate to Serial flasher config.

    Choose Default serial port to configure the serial port. The serial port you configure here is used to write the demo application to your board. On Windows, serial ports have names like COM1. On macOS, they start with /dev/cu. On Linux, they start with /dev/tty.

    Choose Default baud rate to change the default baud rate to use while communicating with your board. Increasing the baud rate can reduce the time required to flash your board. Depending on your hardware, you can increase the default baud rate up to 921600.

  5. After you set up your board's configuration, save and exit the menu.

To build and flash firmware (including boot loader and partition table), and to monitor serial console output, open a terminal (macOS and Linux) or mingw32.exe (Windows). Change directories to <BASE_FOLDER>/demos/espressif/esp32_devkitc_esp_wrover_kit/make and run the following command:

make flash monitor

To monitor the demo, you can subscribe to the MQTT topic where the demo application publishes messages, freertos/demos/echo.

To subscribe to an MQTT topic

  1. Sign in to the AWS IoT console.

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

  3. In Subscription topic, enter freertos/demos/echo, and then choose Subscribe to topic.

    Hello World number and Hello World number ACK messages appear at the bottom of the MQTT client page when the terminal or command prompt where you issued the make flash monitor command returns output similar to the following:

    12 1350 [MQTTEcho] Echo successfully published 'Hello World 0' 13 1357 [Echoing] Message returned with ACK: 'Hello World 0 ACK' 14 1852 [MQTTEcho] Echo successfully published 'Hello World 1' 15 1861 [Echoing] Message returned with ACK: 'Hello World 1 ACK' 16 2355 [MQTTEcho] Echo successfully published 'Hello World 2' 17 2361 [Echoing] Message returned with ACK: 'Hello World 2 ACK' 18 2857 [MQTTEcho] Echo successfully published 'Hello World 3' 19 2863 [Echoing] Message returned with ACK: 'Hello World 3 ACK'

When the demo finishes running, you should see output similar to the following in your terminal or command prompt:

32 6380 [MQTTEcho] Echo successfully published 'Hello World 10' 33 6386 [Echoing] Message returned with ACK: 'Hello World 10 ACK' 34 6882 [MQTTEcho] Echo successfully published 'Hello World 11' 35 6889 [Echoing] Message returned with ACK: 'Hello World 11 ACK' 36 7385 [MQTTEcho] MQTT echo demo finished. 37 7385 [MQTTEcho] ----Demo finished----

Run the Bluetooth Low-Energy Demos

Amazon FreeRTOS support for Bluetooth Low Energy is in public beta release. BLE demos are subject to change.

Amazon FreeRTOS supports Bluetooth Low Energy (BLE) connectivity. You can download Amazon FreeRTOS with BLE from GitHub. The Amazon FreeRTOS BLE library is still in public beta, so you need to switch branches to access the code for your board. Check out the branch named feature/ble-beta.

To run the Amazon FreeRTOS demo project across BLE, you need to run the Amazon FreeRTOS BLE Mobile SDK Demo Application on an iOS or Android mobile device.

To set up the the Amazon FreeRTOS BLE Mobile SDK Demo Application

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

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

For instructions about how to run the MQTT over BLE demo on your board, see the MQTT over BLE demo application.

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

Troubleshooting

  • If you are using a Mac and it does not recognize your ESP-WROVER-KIT, make sure you do not have the D2XX drivers installed. To uninstall them, follow the instructions in the FTDI Drivers Installation Guide for Mac OS 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 crashes. For more information, see Automatically Decoding Addresses on the Espressif website.

  • It is also possible to enable GDBstub for communication with gdb without requiring any special JTAG hardware. For more information, see Launch GDB for GDBStub.

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

  • If pyserial cannot be installed using pip on macOS, download it from pyserial.

  • 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.

Other Notes

  • Required libraries from ESP-IDF are included in Amazon 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 Amazon FreeRTOS.

  • On Window systems, 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

Debugging Code on Espressif ESP32-DevKitC and ESP-WROVER-KIT

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 C232HM MPSSE Cable Connection and Mechanical Details in the datasheet.

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

Debugging on Windows

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. The FTDI C232HM-DDHSL-0 device should appear in Device Manager under Universal Serial Bus Controllers.

  2. From the list of USB controllers, right-click the FTDI C232HM-DDHSL-0 device (the manufacturer is FTDI), and choose Properties. In the properties window, choose the Details tab to see the properties of the device. If the device is not listed, install the Windows driver for FTDI C232HM-DDHSL-0.

  3. Verify that the vendor ID and product ID displayed in Device Manager match the IDs in demos\espressif\esp32_devkitc_esp_wrover_kit\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 it:

    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 box, to the right of the green arrow, choose WinUSB.

    5. From the drop-down box under the target driver box, choose the arrow, and then choose Install Driver. Choose Replace Driver.

  7. Open a command prompt, navigate to <BASE_FOLDER>\demos\espressif\esp32_devkitc_esp_wrover_kit\make and run:

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

    Leave this command prompt open.

  8. Open a new command prompt, navigate to your msys32 directory, and run mingw32.exe. In the mingw32 terminal, navigate to <BASE_FOLDER>\demos\espressif\esp32_devkitc_esp_wrover_kit\make and run make flash monitor.

  9. Open another mingw32 terminal, navigate to <BASE_FOLDER>\demos\espressif\esp32_devkitc_esp_wrover_kit\make and 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

  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 are running a macOS version later than 10.9, use the following command to unload Apple's 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 demos/espressif/esp32_devkitc_esp_wrover_kit/esp32_devkitj_v1.cfg. 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 <BASE_FOLDER>/demos/espressif/esp32_devkitc_esp_wrover_kit/make, and use the following command to run OpenOCD:

    openocd -f esp32_devkitj_v1.cfg -f esp-wroom-32.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 <BASE_FOLDER>/demos/espressif/esp32_devkitc_esp_wrover_kit/make, and run the following command:

    make flash monitor
  12. Open another new terminal, navigate to <BASE_FOLDER>/demos/espressif/esp32_devkitc_esp_wrover_kit/make, and run the following command:

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

    The program should stop at main().

Debugging on Linux

  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 similar to 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 <BASE_FOLDER>/demos/espressif/esp32_devkitc_esp_wrover_kit/make, and use the following command to run OpenOCD:

    openocd -f esp32_devkitj_v1.cfg -f esp-wroom-32.cfg
  6. Open another terminal, navigate to <BASE_FOLDER>/demos/espressif/esp32_devkitc_esp_wrover_kit/make, and run the following command:

    make flash monitor
  7. Open another terminal, navigate to <BASE_FOLDER>/demos/espressif/esp32_devkitc_esp_wrover_kit/make, and run the following command:

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

    The program should stop in main().