ATSAMA5D27-WLSOM1 Evaluation Kit

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

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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

GPIO

The WLSOM1 exposes four banks of GPIO: A, B, C, D. The physical GPIO pins are numbered logically in sequence from PA0 (gpio0) to PD31 (gpio127) when exposed via sysfs or Circuits.GPIO.

Pin	GPIO		Pin	GPIO		Pin	GPIO		Pin	GPIO
PA0	0		PB0	32		PC0	64		PD0	96
PA1	1		PB1	33		PC1	65		PD1	97
PA2	2		PB2	34		PC2	66		PD2	98
PA3	3		PB3	35		PC3	67		PD3	99
PA4	4		PB4	36		PC4	68		PD4	100
PA5	5		PB5	37		PC5	69		PD5	101
PA6	6		PB6	38		PC6	70		PD6	102
PA7	7		PB7	39		PC7	71		PD7	103
PA8	8		PB8	40		PC8	72		PD8	104
PA9	9		PB9	41		PC9	73		PD9	105
PA10	10		PB10	42		PC10	74		PD10	106
PA11	11		PB11	43		PC11	75		PD11	107
PA12	12		PB12	44		PC12	76		PD12	108
PA13	13		PB13	45		PC13	77		PD13	109
PA14	14		PB14	46		PC14	78		PD14	110
PA15	15		PB15	47		PC15	79		PD15	111
PA16	16		PB16	48		PC16	80		PD16	112
PA17	17		PB17	49		PC17	81		PD17	113
PA18	18		PB18	50		PC18	82		PD18	114
PA19	19		PB19	51		PC19	83		PD19	115
PA20	20		PB20	52		PC20	84		PD20	116
PA21	21		PB21	53		PC21	85		PD21	117
PA22	22		PB22	54		PC22	86		PD22	118
PA23	23		PB23	55		PC23	87		PD23	119
PA24	24		PB24	56		PC24	88		PD24	120
PA25	25		PB25	57		PC25	89		PD25	121
PA26	26		PB26	58		PC26	90		PD26	122
PA27	27		PB27	59		PC27	91		PD27	123
PA28	28		PB28	60		PC28	92		PD28	124
PA29	29		PB29	61		PC29	93		PD29	125
PA30	30		PB30	62		PC30	94		PD30	126
PA31	31		PB31	63		PC31	95		PD31	127

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"
  ]