NVIDIA Jetson Nano Developer kit (4Gb)

This is the base Nerves System configuration for the Jetson Nano Developer kit.

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Feature	Description
CPU	Quad-core ARM A57 @ 1.43 GHz
GPU	128-core NVIDIA Maxwell™
Memory	4 GB 64-bit LPDDR4 25.6 GB/s
Storage	MicroSD
Linux kernel	4.9.140 w/ OE4T patches
IEx terminal	UART ttyS0
GPIO, I2C, SPI	Yes - Elixir Circuits
UART	ttyS0 + more via device tree overlay
Camera	MIPI CSI-2 x2 (15-position Flex Connector)
Ethernet	Gigabit Ethernet
WiFi	M.2 Key-E with PCIe x1
USB	4x USB 3.0 A (Host) - USB 2.0 Micro B (Device)

Known issues

This system is under development. Components of the system may change without upgrade paths until the partition structure and included helper libraries are added. It is also unclear what will be required in the system to support cross compiling for CUDA and the inclusions are subject to change. Other quirks and known issues are:

• Reboot sometimes hangs when rebooting too soon after boot. It seems to be associated with sdhci-tegra. When the reboot hangs, eventually the message sdhci-tegra sdhci-tegra.0: Tuning done will be seen and the system will reboot.
• Booting with a display attached results in a white screen and a kernel panic.

Using

Powering the carrier board

The Jetson has the ability to be powered from USB or from the 5V DC Barrel jack, however, it is highly recommended to power the board using the 5V DC barrel jack. Powering the board from USB yields unreliable results.

Adding the system to your project

The most common way of using this Nerves System is create a project with mix nerves.new, add :jetson_nano to the @all_targets list at the top of the mix.exs file, and add the system to the deps:

{:nerves_system_jetson_nano, "~> 0.1", runtime: false, targets: :jetson_nano}

Finally, you can export the Mix target and MIX_TARGET=jetson_nano.

See the Getting started guide for more information.

If you need custom modifications to this system for your device, clone this repository and update as described in Making custom systems

Console access

The console is configured to output to the 6 pin header on the Jetson Nano carrier board that's labeled J44. A 3.3V FTDI cable is needed to access the output.

Provisioning devices

This system supports storing provisioning information in a small key-value store outside of any filesystem. Provisioning is an optional step and reasonable defaults are provided if this is missing.

Provisioning information can be queried using the Nerves.Runtime KV store's Nerves.Runtime.KV.get/1 function.

Keys used by this system are:

Key	Example Value	Description
nerves_serial_number	"12345678"	By default, this string is used to create unique hostnames and Erlang node names. If unset, it defaults to part of the BBB's serial number.

The normal procedure would be to set these keys once in manufacturing or before deployment and then leave them alone.

For example, to provision a serial number on a running device, run the following and reboot:

iex> cmd("fw_setenv nerves_serial_number 12345678")

This system supports setting the serial number offline. To do this, set the NERVES_SERIAL_NUMBER environment variable when burning the firmware. If you're programming MicroSD cards using fwup, the commandline is:

sudo NERVES_SERIAL_NUMBER=12345678 fwup path_to_firmware.fw

Serial numbers are stored on the MicroSD card so if the MicroSD card is replaced, the serial number will need to be reprogrammed. The numbers are stored in a U-boot environment block. This is a special region that is separate from the application partition so reformatting the application partition will not lose the serial number or any other data stored in this block.

Additional key value pairs can be provisioned by overriding the default provisioning.conf file location by setting the environment variable NERVES_PROVISIONING=/path/to/provisioning.conf. The default provisioning.conf will set the nerves_serial_number, if you override the location to this file, you will be responsible for setting this yourself.

Linux and U-Boot versions

The Jetson nano Linux kernel originates from the NVIDIA Linux4Tegra (L4T) repository at nv-tegra.nvidia.com/linux-4.9.git. The kernel expects a number of other repositories to be located at paths relative to the kernel. OpenEmbedded4Linux (OE4L) has created a copy of the NVIDIA Tegra upstream kernel with these files pulled into the kernel tree and the relative paths have been updated to reference the in tree locations. OE4L has also added a number of patches required to compile the kernel using GCC 9 / 10.

U-Boot originates from nv-tegra.nvidia.com/3rdparty/u-boot.git with patches originally coming from OE4T. The OE4T U-Boot patches have been updated to work with U-Boot 2021.01.

Image credit: This image is from Nvidia.