/**
 * @defgroup    boards_firefly Firefly Board
 * @ingroup     boards
 * @brief       Support for the Firefly board

Zolertia Firefly platform
============================================

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@image html "http://i.imgur.com/m2acovV.png?1" "Firefly"

The Firefly platform (Revision A) is a IoT Hardware development platform based
on TI's CC2538 system on chip (SoC), featuring an ARM Cortex-M3 with 512KiB
flash, 32KiB RAM, double RF interface (Sub-1GHz CC1200 RF transceiver), and the
following goodies:

- ISM 2.4-GHz IEEE 802.15.4 & Zigbee compliant.
- ISM 868-, 915-, 920-, 950-MHz ISM/SRD Band.
- AES-128/256, SHA2 Hardware Encryption Engine.
- ECC-128/256, RSA Hardware Acceleration Engine for Secure Key Exchange.
- Power consumption down to 150nA using our shutdown mode.
- Flashing over BSL without requiring to press any button to enter bootloader mode.
- Built-in battery charger (500mA), Energy Harvesting and Solar Panels to be connected to standards LiPo batteries.
- Power input with 2.3-5.1VDC depending on battery or USB supply


Port Features
=============
In terms of hardware support, the following drivers have been implemented for
the CC2538 System-on-Chip:

- UART
- Random number generator
- Low Power Modes
- General-Purpose Timers
- I2C/SPI library
- LEDs
- Buttons
- RF 2.4GHz built-in in CC2538

And under work or pending at CC2538 base CPU:

- Built-in core temperature and battery sensor.
- CC1200 sub-1GHz radio interface.
- Micro-SD external storage.
- ADC
- USB (in CDC-ACM).
- uDMA Controller.

Requirements
============

- Toolchain to compile RIOT for the CC2538
- Drivers to enable your host to communicate with the platform
- Built-in BSL programming over USB using cc2538-bsl (included)


Install a Toolchain
-------------------
The toolchain used to build is arm-gcc, to check if it is currently installed run:

    $ arm-none-eabi-gcc -v
    Using built-in specs.
    Target: arm-none-eabi
    Configured with: /scratch/julian/lite-respin/eabi/src/gcc-4.3/configure
    ...
    (skip)
    ...
    Thread model: single
    gcc version 4.3.2 (Sourcery G++ Lite 2008q3-66)

Else install from <https://launchpad.net/gcc-arm-embedded>


Drivers
-------
The Firefly features a CP2104 serial-to-USB module, the driver is commonly found in most OS, but if required it can be downloaded
from <https://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-drivers>


### For the CC2538EM (USB CDC-ACM)
The Firefly has built-in support for USB 2.0 USB, Vendor and Product IDs are the following:

  * VID 0x0451
  * PID 0x16C8

On Linux and macOS this is straightforward, on windows you need to install the following driver:

<https://github.com/alignan/lufa/blob/remote-zongle/LUFA/CodeTemplates/WindowsINF/LUFA%20CDC-ACM.inf>

And replace the IDs accordingly.

### Device Enumerations
For the UART, serial line settings are 115200 8N1, no flow control.

Once all drivers have been installed correctly:

On windows, devices will appear as a virtual `COM` port.

On Linux, devices will appear under `/dev/`.

On macOS, `/dev/tty.SLAB_USBtoUARTx`.

On Linux:

- Firefly over CP2104: `ttyUSB0`
- Firefly over USB driver (in CDC-ACM): `ttyACMn` (n=0, 1, ....)

Emulator
========

To emulate this board you need an updated version of
[renode](https://github.com/renode/renode) installed, at least version 1.9.

```
BOARD=firefly make all emulate
```

More Reading
============
1. [Zolertia Firefly website][remote-site]
2. [Zolertia Wiki page][zolertia-wiki]
3. [CC2538 System-on-Chip Solution for 2.4-GHz IEEE 802.15.4 and ZigBee applications (SWRU319B)][cc2538]
4. [CC1200 sub-1GHz RF transceiver][cc1200]

[remote-site]: https://zolertia.io/product/firefly "Zolertia Firefly"
[zolertia-wiki]: https://github.com/Zolertia/Resources/wiki
[cc1200]: http://www.ti.com/product/cc1200     "CC1200"
[cc2538]: http://www.ti.com/product/cc2538     "CC2538"

*/