/**
@defgroup    boards_sodaq-autonomo SODAQ Autonomo
@ingroup     boards
@brief       Support for the SODAQ Autonomo board.

## Overview

The `SODAQ Autonomo` is a board by SODAQ featuring a ATSAMD21J18A. The SAMD21
is a ARM Cortex-M0+ micro-controller.  It has 256Kb of flash memory and 32Kb of
RAM.

The Autonomo is available from the SODAQ [shop](http://shop.sodaq.com/).

## Hardware

![sodaq-autonomo image](http://static.webshopapp.com/shops/104792/files/050759716/sodaq-sodaq-autonomo.jpg)


### MCU
| MCU        | ATSAMD21J18A      |
|:------------- |:--------------------- |
| Family | ARM Cortex-M0+        |
| Vendor        | Atmel                 |
| RAM        | 32Kb                  |
| Flash      | 256Kb             |
| Frequency  | up to 48MHz |
| FPU        | no                |
| Timers | 6 (1x 16-bit, 2x 24-bit, 3x 32-bit)   |
| ADCs       | 1x 12-bit (8 channels)            |
| UARTs      | max 6 (SERCOMs shared with SPI and I2C)               |
| SPIs       | max 6 (see UART)                  |
| I2Cs       | max 6 (see UART)              |
| Vcc        | 1.8V - 3.6V           |
| Datasheet  | [Datasheet](http://www.atmel.com/Images/Atmel-42181-SAM-D21_Datasheet.pdf) |

### User Interface

1 LED:

| Device | PIN |
|:------ |:--- |
| LED0   | PA19 |


## Implementation Status

Please refer to [this tracker](https://github.com/RIOT-OS/RIOT/issues/1646)
to see which projects are work in progress and who is the contact person for
this.  Notice that the initial support for the Autonomo was based on
samr21-xpro.  At some point we will add a separate issue to track changes for
this board.

| Device | ID        | Supported | Comments  |
|:------------- |:------------- |:------------- |:------------- |
| MCU        | samd21    | partly    | Energy saving modes not fully utilized|
| Low-level driver | GPIO    | yes       | |
|        | PWM       | yes       | |
|        | UART      | yes           | two UARTs by now|
|        | I2C       | yes       | |
|        | SPI       | yes       | |
|               | ADC           | yes           | PA04 & PA05 disabled by default due to EDBG's use of them for UART, can be enabled from `periph_conf.h`|
|        | USB       | no        | |
|        | RTT       | yes       | |
|        | RTC       | yes       |  |
|        | RNG       | no        | no HW module |
|        | Timer     | yes           | |



## Features of the board

Besides the SAMD21 the board has the following features:

| Feature | Description |
|:------ |:--- |
| Compatibility        | Arduino M0 compatible |
| Size                 | 58.5 x 33.5 mm |
| Operating Voltage    | 3.3V |
| Digital I/O Pins     | 16, with 12 PWM, UART, SPI and TWI (I2C) |
| Analog Input Pins    | 6, 12-bit ADC channels |
| Analog Output Pins   | 10-bit DAC |
| External Interrupts  | Available on all pins except pin 4 |
| DC Current per I/O pin | 7 mA |
| EEPROM               | Up to 16KB by emulation |
| Clock Speed          | 48 MHz |
| Debug                | Serial Wire Interface |
| Communications       | Bee compatible slot for communication modules with software switchable power |
| Storage              | 16Mbit Dataflash Module and Micro SD card holder |
| Power                | 5V USB power and/or 3.7V LiPo battery |
| Power switch         | Software switchable power for connected devices up to 1A |
| Charging             | Solar charge controller, up to 500mA charge current|
| LED's                | Yellow charge LED and green LED on pin 13 |

## Flashing the device

The Autonomo has a 10 pin header compatible with the Atmel-ICE.  The standard
method for flashing RIOT to the sodaq-autonomo is using OpenOCD. For this to
work properly, **you have to make sure to use a very recent version of
OpenOCD**.  Arduino-IDE comes with openocd v0.9.0  which is known to work.  Also
Ubuntu 16.04 has openocd v0.9.0.

Refer to https://github.com/RIOT-OS/RIOT/wiki/OpenOCD for building OpenOCD
and make sure "cmsis-dap" and "hidapi-libusb" are enabled.

## Supported Toolchains

To build software for the autonomo board we strongly recommend the usage of
the [GNU Tools for ARM Embedded Processors](https://launchpad.net/gcc-arm-embedded) toolchain.


## Known Issues / Problems

### Stack sizes
The default stack sizes have not been tuned properly yet. If in doubt why
your application crashes try increasing the default stack sizes and use `ps` to
find out how much stack is being used.
Tracked in https://github.com/RIOT-OS/RIOT/issues/2228
 */