.. _particle_boron:

Particle Boron
##############

Overview
********

The Particle Boron is a cellular-enabled development board with a
Nordic Semiconductor nRF52840 for mesh support and an LTE or 2G/3G
modem.  The board was developed by Particle Industries and has a SWD
connector on it for programming.

It is equipped with a onboard LIPO circuit and conforms to the
Adafruit Feather formfactor.

The Particle Boron board provides support for the Nordic Semiconductor nRF52840
ARM |reg| Cortex |reg|-M4F SoC with an integrated 2.4 GHz transceiver supporting
Bluetooth |reg| Low Energy and IEEE |reg| 802.15.4.

For more information about the Particle Boron board:

- `Boron Datasheet`_
- `Boron Hardware Files`_

Hardware
********

On the front of the board are RGB-LED, LED and LIPO circuitry.
The RGB-LED is controlled by the nRF52840 via GPIO pins.

.. figure:: img/particle_boron.png
     :width: 150px
     :align: center
     :alt: Particle Boron

     Particle Boron (Credit: Particle Industries)

Power supply
============

The board is optimized for low power applications and supports two
power source configurations: battery and micro USB connector.

It contains circuitry for LIPO usage and can be charged via the USB port.

Supported Features
==================

The particle_boron board configuration supports the following
hardware features:

+-----------+------------+----------------------+
| Interface | Controller | Driver/Component     |
+===========+============+======================+
| NVIC      | on-chip    | nested vectored      |
|           |            | interrupt controller |
+-----------+------------+----------------------+
| RTC       | on-chip    | system clock         |
+-----------+------------+----------------------+
| UART      | on-chip    | serial port          |
+-----------+------------+----------------------+
| I2C       | on-chip    | i2c                  |
+-----------+------------+----------------------+
| SPI       | on-chip    | spi                  |
+-----------+------------+----------------------+
| GPIO      | on-chip    | gpio                 |
+-----------+------------+----------------------+
| FLASH     | on-chip    | flash                |
+-----------+------------+----------------------+
| RADIO     | on-chip    | Bluetooth            |
+-----------+------------+----------------------+

Other hardware features are not supported by the Zephyr kernel.

Connections and IOs
===================

Please see the `Boron Datasheet`_ for header pin assignments, which are
common to all Feather-compatible Particle boards.  Some peripherals are
available to applications through DTS overlay include directives:

- ``mesh_feather_spi_spi3.dtsi`` exposes SPI3 on labeled Feather
  SPI pins
- ``mesh_feather_spi1_spi3.dtsi`` exposes SPI3 on labeled Feather
  SPI1 pins
- ``mesh_feather_uart1_rtscts.dtsi`` adds hardware flow control to
  labeled Feather UART pins

LED
---

* LED0 (blue)
* LED1 (red)
* LED2 (green)
* LED3 (blue)

Push buttons
------------

* SW0 via MODE
* SW1 via RESET

I2C
---

* TWI0 enabled on labeled header (SDA/SCL)
* TWI1 enabled for internal power management ICs

SPI
---

* SPI0 disabled due to TWI0 conflict
* SPI1 disabled due to TWI1 conflict
* SPI2 internal to 32 Mb CFI flash chip
* SPI3 selectable with overlay (SPI or SPI1)

UART
----

* UARTE0 enabled RX/TX on labeled header (UART1); add RTS/CTS with overlay
* UARTE1 internal to u-blox cellular modem

Programming and Debugging
*************************

Applications for the ``particle_boron`` board configuration can be
built and flashed in the usual way (see :ref:`build_an_application`
and :ref:`application_run` for more details).

Flashing
========

Build and flash an application in the usual way, for example:

.. zephyr-app-commands::
   :zephyr-app: samples/basic/blinky
   :board: particle_boron
   :goals: build flash

Debugging
=========

You can debug an application in the usual way.  Here is an example for the
:ref:`hello_world` application.

.. zephyr-app-commands::
   :zephyr-app: samples/hello_world
   :board: particle_boron
   :maybe-skip-config:
   :goals: debug


Testing the LEDs and buttons
****************************

There are 2 samples that allow you to test that the buttons (switches) and
LEDs on the board are working properly with Zephyr:

* :ref:`blinky-sample`
* :ref:`button-sample`

You can build and flash the examples to make sure Zephyr is running correctly on
your board.

.. _Boron Datasheet:
   https://docs.particle.io/datasheets/cellular/boron-datasheet/

.. _Boron Hardware Files:
   https://github.com/particle-iot/boron