ATSAMA5D27-WLSOM1 Evaluation Kit

https://www.microchip.com/DevelopmentTools/ProductDetails/PartNO/DM320117

^{Image credit}

Feature	Description
CPU	500 MHz ARM Cortex-A5
Memory	256M DDR2
Storage	MicroSD
GPIO, I2C, SPI	Yes - Elixir Circuits
UART	ttyS0
Ethernet	Yes
Video	Yes
Camera Interface	Yes - Parallel ISC

Docs

• ATSAMA5D27-WLSOM1-EK1 dev kit user guide
• ATSAMA5D27-WLSOM1 datasheet
• SAMA5D2 series datasheet

Using

The most common way of using this Nerves System is create a project with mix nerves.new and to export MIX_TARGET=sama5d27_wlsom1_ek. 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

UART

Header	Device
mikro BUS 1	ttyS3
mikro BUS 2	ttyS2

Wi-Fi

The WLSOM1 contains a ATWILC3000 Wi-Fi / Bluetooth module. Wi-Fi can be enabled by loading the kernel module.

iex> cmd "modprobe wilc-sdio"

If the Wi-Fi module is set to access point (AP) mode, it will need to be reset if its VintageNet configuration is updated at runtime.

cmd "rmmod wilc-sdio"
cmd "modprobe wilc-sdio"

The Wi-Fi module supports 8 connected devices in access point (AP) mode.

Bluetooth

The ATWILC3000 includes Bluetooth Low Energy capabilities that can be utilized after following a specific configuration and startup sequence. In general, there are two routes that can be taken to make use of Bluetooth in Nerves: BlueZ and BlueHeron. So far, only BlueZ has been tested on the WLSOM1.

BlueZ

In order to use the BlueZ stack, there are a number of config options and packages that are required.

Add these config options to the Linux defconfig:

CONFIG_BT_HCIUART=m
CONFIG_BT_HCIUART_H4=y

Add these packages to nerves_defconfig:

BR2_PACKAGE_BLUEZ5_UTILS=y
BR2_PACKAGE_BLUEZ5_UTILS_CLIENT=y
BR2_PACKAGE_BLUEZ5_UTILS_TOOLS=y
BR2_PACKAGE_BLUEZ5_UTILS_DEPRECATED=y

Note: The Bluetooth power up sequence requires both dbus-daemon and bluetoothd. It is recommended to use either MuonTrap or Ports for running them as background processes.

Here is an example that uses Ports for the startup sequence:

System.cmd("modprobe", ["wilc-sdio"])
Process.sleep(5000)

File.write("/dev/wilc_bt", "BT_POWER_UP")
Process.sleep(1000)

File.write("/dev/wilc_bt", "BT_DOWNLOAD_FW")
Process.sleep(100)

File.rm_rf("/run/messagebus.pid")
File.mkdir_p("/run/dbus")

Port.open(
  {:spawn_executable, "/usr/bin/dbus-daemon"},
  [:binary, :exit_status, :stderr_to_stdout,
    args: ["--system", "--nofork"]]
)

System.cmd("hciattach", ["/dev/ttyS1", "any", "115200", "noflow", "nosleep"])
Process.sleep(300)

System.cmd("hciconfig", ["hci0", "up"])

File.mkdir_p("/data/bluetooth")

Port.open(
  {:spawn_executable, "/usr/libexec/bluetooth/bluetoothd"},
  [:binary, :exit_status, :stderr_to_stdout,
    args: ["-p", "time", "-n", "-C", "--localstatedir=/data"]]
)

bluetoothctl can be used to run various Bluetooth Low Energy operations. Here is an example of how to open a port for running bluetoothctl:

bluetoothctl = Port.open(
  {:spawn_executable, "/usr/bin/bluetoothctl"},
  [:binary, :exit_status, :stderr_to_stdout]
)

Ethernet

A unique hardware address for the eth0 interface is programmed into the QSPI flash memory from the factory and is read set by U-Boot. Inorder to read from the flash memory, you will need to ensure the QSPI flash is being powered by removing the shunt from jumper J8 labeled "Disable Boot".

The hardware address of the interface can also be forced by setting the U-Boot environment variable ethaddr. If neither of these locations are accessible, Linux will assign a random hardware address to the interface on every boot.

Supported USB Wi-Fi Devices

The base image includes drivers and firmware for Ralink RT53xx (rt2800usb driver) and RealTek RTL8712U (r8712u driver) devices.

We are still working out which subset of all possible Wi-Fi dongles to support in our images. At some point, we may have the option to support all dongles and selectively install modules at packaging time, but until then, these drivers and their associated firmware blobs add significantly to Nerves release images.

If you are unsure what driver your Wi-Fi dongle requires, run Debian and configure Wi-Fi for your device. At a shell prompt, run lsmod to see which drivers are loaded. Running dmesg may also give a clue. When using dmesg, reinsert the USB dongle to generate new log messages if you don't see them.

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.

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.

Hostname

By default the hostname will only include the last 4 digits of the board identifier. If you would rather use the entire identifier, set the following in your config/target.exs file:

config :nerves,
  erlinit: [
    uniqueid_exec: "boardid"
  ]