NXP Semiconductors i.MX 8M User manual

NXPSemiconductors
Document Number: IMX8MAVSUG
User's Guide
Rev.
2
,
01/2019
User's Guide for NXP i.MX 8M Development
Kit for Amazon AVS
1.Introduction
The NXP i.MX 8M Development Kit for Amazon
Alexa Voice Service (AVS) enables its wide customer
base to easily integrate Alexa into their next generation
design based on i.MX processors. The development kit
consists of a 2-Mic array and the Pico i.MX 8M
development kit, both optimized to deliver a low cost
but flexible design to enable fast development to
production.
To enable customers to deliver a high-quality audio
experience we have partnered with DSP Concepts for
audio algorithms including echo cancellation, beam-
forming, and noise reduction to be delivered in
software. This results in a single chip solution, lowering
overall design cost, while ensuring customers to have
the support and expertise needed to deliver a high-
quality user experience in a short development time.
Contents
1. Introduction........................................................................1
2. What’s in the kit.................................................................2
3. Amazon account setup .......................................................4
4. Hardware setup ..................................................................9
5. Flash the board................................................................. 12
6. Install Alexa SDK ............................................................ 15
7. Running sample AVS App............................................... 26
8. Download MRM packages............................................... 29
9. Testing MRM................................................................... 34
10. Enable auto start of Alexa sample.................................. 44
11. Testing audio................................................................. 46
11.1. Testing audio with DSPC ..................................... 46
11.2. Testing Audio without DSPC (or before executing
setupAVS.sh) ..................................................................... 47
12. References ..................................................................... 48
12.1. Support ................................................................. 48
12.2. Key terms ............................................................. 48
12.3. Speaker references ................................................ 48
12.4. Ordering information and web links ..................... 48
© 2018 NXP B.V.

What’s in the kit
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This user’s guide provides step-by-step instructions for setting up the development kit and accessing and
testing Amazon AVS including account, hardware and software setup. When finished, you will have a
fully functioning prototype with Alexa built-in that uses the TechNexion Voice Hat 2-Mic Development
Kit as an audio front end, and the PICO-PI-IMX8M development board as the processor handling the
Alexa wake word recognition and interface to Amazon AVS.
The NXP i.MX 8M Development Kit for Amazon AVS is available on
https://www.amazon.com/dp/B07HBB1L5Kandhttps://shop.technexion.com/pico-pi-imx8m-
alexa.html.
2. What’s in the kit
Figure 1. NXP i.MX 8M development kit for Amazon AVS components
NOTE
Antistatic precautions are recommended for assembling the kit.

Amazon account setup
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Figure 2. NXP i.MX 8M Development Kit with connected TechNexion Hat
In addition to the kit, you will also require:
1. A windows PC with internet connection and a USB port.
2. USB 5 V power adaptor (or use an USB port capable of sourcing power from a PC). Some PC’s may
not provide enough power to the board and will re-boot. If this occurs please use a 5V charger
current instead.
3. Download the serial-to-USB drivers for serial debugging found here.
4. Multi-Room Music (MRM) feature enables music to be played and controlled across multiple,
compatible Alexa devices at the same time. In order to test MRM, you will need a second voice
kit or a MRM-enabled Alexa device.
NOTE ON SPEAKERS
The speakers provided in the kit are for initial prototyping only. For best
Acoustic Echo Cancellation (AEC) and Barge-in performance of the voice
input system, low distortion audio reproduction is important. High quality
speakers are recommended and for space restrained applications, single
transducer configurations perform better than multiple transducers with a
cross-over network.
Go to speaker references section for recommendations.

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Amazon account setup
3. Amazon account setup
To setup a developer account with Amazon, please perform the following steps.
1. Create a free developer account at developer.amazon.com. You can review the AVS Terms and
Agreements here. Create Alexa Voice Service (AVS) project, as shown in Figure 3.
Figure 3. Create Amazon account
2. Follow the steps as explained at https://github.com/alexa/avs-device-sdk/wiki/Create-Security-
Profile#product-information to register your product and create a device and security profile.
After entering in the Security Profile and Security Profile description sections, make sure to
select Other devices and platforms, as shown in Figure 4. Enter in the Client ID section and
select Generate ID.

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Amazon account setup
Figure 4. Generate client ID
NOTE
When prompted for the Client ID, make sure to use the Client ID from the
Other devices and platforms section.
3. On the Products page, click Manage and you can view your product details, as shown in Figure
5.
Figure 5. Product page
When done, the product profile is as shown in Figure 6 to Figure 9.

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Amazon account setup
Figure 6. Product Details –Information I
Figure 7. Product Details –Information II

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Amazon account setup
Figure 8. Product Details –Security Profile I

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Hardware setup
Figure 9. Product Details –Security Profile II

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Hardware setup
4. Hardware setup
This section will describe how to connect the Voice Hat board to the PICO-PI-IMX8M board.
1. Remove the jumpers on J11 on the Pico-Pi baseboard, as shown in Figure 10.
Figure 10. J11 on Pico-Pi baseboard
2. Change J2 jumpers to allow the board to boot the preloaded Linux image from eMMC, as shown
in Figure 11.
Figure 11. J2 on Pico-Pi baseboard
3. Verify the pin headers and jumper settings on the back of the audio hat, as shown in Figure 12
and Figure 13.

Hardware setup
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Figure 12. Back of Voice HAT (header settings)
Figure 13. Back of Voice HAT (switch settings from 1 to 8:10101010)
4. If using Wifi, connect the antennae to the antennae connector located on the top left of the SOM
5. Install the pin extenders on the Pico-Pi base board.
6. Plug the audio hat into the pin extenders on the Pico-Pi board, as shown in Figure 14
Figure 14. Audio hat plugged into the pico-pi board

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Flash the board
Steps:
1. Plug in the USB-Micro cable into the PC and the Pico-Pi board for serial debug
2. Plug in the USB-C cable into the Pico-Pi board and PC for power
3. Connect the speakers to the audio hat’s speaker connectors
Figure 15. Hardware connections on the Voice Kit
Figure 16. Dev kit plugged-in

Flash the board
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5. Flash the board
The NXP i.MX 8M Development Kit for Amazon AVS comes pre-loaded with a Yocto Linux image,
requiring the user to run the scripts to build and run the sample AVS app.
Please check for the latest version of software at https://www.nxp.com/products/processors-and-
microcontrollers/arm-based-processors-and-mcus/i.mx-applications-processors/i.mx-8-
processors/i.mx-8m-development-kit-for-amazon-alexa-voice-service:FAR-FIELD-VOICE-
SERVICES
. If the board does not contain an image or if the software is not up-to-date with the latest release, then
you can download the image from nxp.com/xxx and flash the board by following the steps described in
this section. If you do not wish to flash the image but use the pre-loaded image, skip section 5 Flash the
board and go to section 6 Install Alexa SDK.
NOTE
The image is configured for Pico-8M with 1 GB DDR. Flashing the image
on any variant of Pico-8M (such as 2/3 GB) may cause the boot failure.
All NXP i.MX 8M Development Kits for Amazon AVS are configured with the correct memory
configuration. If you are using a Pico-8M board purchased through a different channel, please confirm
the memory configuration before flashing the image.
NOTE
If needed, download the serial-to-USB drivers found here.
1. Change J2 jumpers to put the Pico-Pi in serial download mode, as shown in Figure 17.
Figure 17. Change J2 jumpers

Flash the board
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2. Connect the Pico-Pi to your Windows PC using the provided USB-A to USB-C cable for power.
3. Connect the Pico-Pi to your Windows PC using the provided USB micro cable for serial
download.
4. Download the latest manufacturing tool, pico-imx8m_mfgtool-XXXXX.zip, from
ftp://ftp.technexion.net/development_resources/development_tools/installer/.
5. Extract the zip file to your Windows PC.
6. Navigate to mfgtools-without-rootfs_for_all_ddr\mfgtools-without-rootfs\mfgtools.
7. Double click the mfgtool2-wand_pi_8m-attach_eMMC_as_usb_mass_storage.vbs to run the
VBScript, as shown in Figure 18.
Figure 18. Run VBScript
8. Click the Start button and wait for the progress bar to 100%, as shown in Figure 19.
Figure 19. Progress of running VBScript
9. Download the demo image package from https://www.nxp.com/products/processors-and-
microcontrollers/arm-based-processors-and-mcus/i.mx-applications-processors/i.mx-8-
processors/i.mx-8m-development-kit-for-amazon-alexa-voice-service:FAR-FIELD-VOICE-
SERVICES and extract the compressed image file.
10. Download and install Win32 Disk Imager from
https://sourceforge.net/projects/win32diskimager/.
11. Use the Win32 Disk Imager to flash the extracted image to the board, as show in Figure 20.

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Install Alexa SDK
Figure 20. Write operation
NOTE
If Win32 Disk Imager pops up a warning about hardware corruption, just
ignore it and proceed.
12. After a successful write, disconnect the USB-C cable and change J2 jumpers back to allow the
board to boot from eMMC, as shown in Figure 21.
Figure 21. J2 jumpers
13. Reconnect the USB-C cable to the Pico-Pi board to boot into the newly-installed image.

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Install Alexa SDK
6. Install Alexa SDK
This section describes how to access and test the Amazon sample AVS application.
1. Power on the board. Make sure that everything is connected before the system boots up. See
Section 4 Hardware setup.
2. Open a serial console (Putty or Tera Term) on your PC and select the board’s COM port number
enumerated by the host system.
NOTE
The USB-serial chip on i.MX 8M enumerates two serial ports. Check both
ports for a prompt.
If needed, download the serial-to-USB drivers here.
Use values shown in Figure 22 in the Port Settings section.
Figure 22. Port Settings
An NXP welcome prompt pops up, as shown in Figure 23.

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Install Alexa SDK
Figure 23. NXP Welcome display massage
3. On the serial console, press Enter to see the login splash and then login using credential as root.
Figure 24. Login as root
The first time you boot the image, after login you will be asked to accept the NXP EULA. Please
read and accept the NXP License Agreement.

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Figure 25. NXP EULA Acceptance

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Install Alexa SDK
4. Enable Wi-Fi, log in, and connect to the Wi-Fi network with your SSID and password.
Run start_wifi.sh with SSID and password as parameters.
—./start_wifi.sh SSID password
NOTE
You only need to pass the SSID and PASSWORD as arguments the first
time you register/connect to a Wi-Fi network. Next time you can run
wifiSetup.sh without any arguments to connect to the latest Wi-Fi
network you have registered.
Figure 26. Connecting to Wi-Fi network log
NOTE
Use quotation marks if your SSID or password has spaces, as shown in
Figure 26.
Check whether you have obtained a valid IP address from your Wi-Fi network.
Use ifconfig to check your IP address.

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Install Alexa SDK
Figure 27. Check IP address
5. Alexa Multi-Room Music (MRM) is a feature that enables music to be played and controlled
across multiple, compatible Alexa devices at the same time. If you wish to enable this feature, go
to Section 8 Download MRM packages to download the required MRM packages.
NOTE
You will need an additional kit or an MRM enabled Alexa device to test
MRM in Section 9 Testing MRM.
If you wish to test the audio before downloading the Alexa SDK, see
Section 11 Testing audio.
6. We are ready to start the installation of the Alexa SDK now. Go to /home/root/Alexa_SDK
directory and run the setupAVS.sh script to start.
Change to the Alexa_SDK directory and run the setupAVS.sh script.
—cd ~/Alexa_SDK
—./setupAVS.sh
NOTE
You need to run the setupAVS.sh again if credentials is reset or changed.
The setupAVS script will guide you to the Alexa SDK installation on your Pico 8M board.
The first time when you run setupAVS.sh, it will display as follows:
You already have an AVS configuration setup on place...
What do you want to do?
Start over the whole AVS setup ....... 1
Just set new AVS Credentials ......... 2
Calibrate speakers .................. 3
Type the number of your selection and press Enter ...

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Enter 1 for Type the number of your selection and press Enter... then it will ask whether you
want to install MRM and DSPC SW.
Do you want to install/Enable MRM (Multi Room Music) [Y/N]?
Do you want to install/Enable DSPC SW (Recommended) [Y/N]?
Select Y if you want to install MRM and Y if you want to enable DSPC software
(recommended).
MRM is for enabling the Multi-Room-Music functionality on Alexa_SDK.
Use of MRM and other Amazon software is subject to license terms from Amazon,
which can be found in the Appendices to the NXP Software License Agreement and
any additional terms provided with the delivery of the Amazon software.
The DSPC Software is the Audio Front End for (Acoustic Echo Cancelation,
Beamforming, and so on) used for the Pico8M + VoiceHat kit.
Figure 28. Run the setupAVS.sh script
If you have enabled MRM, the setupAVS.sh script will use the two copied packages to install
the
MRM library and apply the patch to the Alexa_SDK.
A successful installation message pops up, as shown in 29.
Figure 29. Successful MRM installation