Build Alexa SDK (AVS) image for i.mx7D PicoPi board (with Yocto Morty, Kernel4.9)

Document created by Juan Gutierrez Employee on May 18, 2018
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Recipes to include Amazon's Alexa Voice Services in your applications.

Step 1 : Get iMX Yocto AVS setup environment

Review the steps under Chapter 3 of the i.MX_Yocto_Project_User'sGuide.pdf on the L4.X LINUX_DOCS to prepare your host machine. Including at least the following essential Yocto packages

$ sudo apt-get install gawk wget git-core diffstat unzip texinfo \
  gcc-multilib build-essential chrpath socat libsdl1.2-dev u-boot-tools

Install the i.MX NXP AVS repo

Create/Move to a directory where you want to install the AVS yocto build enviroment.

Let's call this as <yocto_dir>

$ cd <yocto_dir>
$ repo init -u -b master -m imx-alexa-sdk-4.9.11.xml

Download the AVS BSP build environment:

$ repo sync

Step 2: Setup yocto for Alexa_SDK image with AVS-SETUP-DEMO script:

Run the avs-setup-demo script as follows to setup your environment for the imx7d-pico board:

$ MACHINE=imx7d-pico DISTRO=fsl-imx-x11 source -b <build_sdk>

Where <build_sdk> is the name you will give to your build folder.

After acepting the EULA the script will prompt if you want to enable: a

Sound Card selection

The following Sound Cards are supported on the build:

  • SGTL (In-board Audio Codec for PicoPi)
  • 2-Mic Synaptics/Conexant
  • 2-Mic TechNexion Voice Hat (with DSPConcepts SW)

The script will prompt to select the soundcard you will be using:

Which Sound Card are you going to use?
Sigmatel .............................. 1
Synaptics/Conexant .................... 2
VoiceHat (for DSPConcepts SW) ......... 3
Type the number of your selection and press Enter...

Install Alexa SDK

Next option is to select if you want to pre-install the AVS SDK software on the image.

Do you want to build/include the AVS_SDK package on this image(Y/N)?

If you select YES, then your image will contain the AVS SDK ready to use (after authentication). Note this AVS_SDK will not have WakeWord detection support, but it can be added on runtime.

If your selection was NO, then you can always manually fetch and build the AVS_SDK on runtime. All the packages dependencies will be already there, so only fetching the AVS_SDK source code and building it is required.

Install WiFi support

Te WiFi support is optional and requires to get from NXP an additional meta-picopi-wifi layer. Contact NXP to get this layer to be able to support WiFi on your image

The image will prompt:

Do you want to include WiFi support on this image(Y/N)?

Select YES if you already have the complementary meta-avs-demos-wifi layer

Finish avs-image configuration

At the end you will see a text according with the configuration you select for your image build.

Next is an example for a Preinstalled AVS_SDK with Synaptics Sound Card support and WiFi/BT not enabled for PicoPi board.

AVS configuration is now ready at conf/local.conf
- Sound Card = Synaptics
- Alexa SDK 1.7 pre-installed
- Wifi supported
You are ready to bitbake your AVS demo image now:
bitbake avs-image
If you want to use QT5DisplayCards, use then:
bitbake avs-image-qt5

Step 3: Build the AVS image

Go to your <build_sdk> directory and start the build of the avs-image

There are 2 options

  • Regular Build:

    $ cd  <yocto_dir>/<build_sdk>   
    $ bitbake avs-image
  • With QT5 support included:

    $ cd  <yocto_dir>/<build_sdk>   
    $ bitbake avs-image-qt5

The image with QT5 is useful if you want to add some GUI for example to render DisplayCards.

Step 4 : Deploying the built images to SD/MMC card to boot on target board.

After a build has succesfully completed, the created image resides at


In this directory, you will find imx7d-pico-avs--.sdcard image or imx7d-pico-avs-qt5--.sdcard, depending on the build you chose on Step3.

To Flash the .sdcard image into the eMMC device of your PicoPi board follow the next steps:

  • Download the bootbomb flasher

  • Follow the instruction on Section 4. Board Reflashing of the Quick Start Guide for AVS kit to setup your board on flashing mode.

  • Copy the built SDCARD file

    $ sudo dd if=imx7d-pico-avs.sdcard of=/dev/sd<partition> bs=1M && sync
    $ sync
  • Properly eject the pico-imx7d board:

    $ sudo eject /dev/sd<partition>

NXP Documentation

Refer to the Quick Start Quide for AVS SDK to fully setup your PicoPi board with Synaptics 2Mic and PicoPi i.mx7D

For a more comprehensive understanding of Yocto, its features and setup; more image build and deployment options and customization, please take a look at the i.MX_Yocto_Project_User's_Guide.pdf document from the Linux documents bundle mentioned at the beginning of this document.

For a more detailed description of the Linux BSP, u-boot use and configuration, please take a look at the i.MX_Linux_User's_Guide.pdf document from the Linux documents bundle mentioned at the beginning of this document.

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