.. zephyr:board:: serpente

Overview
********

The Serpente is a very small low-cost development and prototyping
board equipped with 4MiB flash storage, a PWM enabled RGB led and 6 I/O pins.
The board comes with 3 different USB connector options: USB Type-C plug,
USB Type-C socket and USB Type-A plug.

Hardware
********

- ATSAMD21E18A ARM Cortex-M0+ processor at 48 MHz
- 256 KiB flash memory and 32 KiB of RAM
- Extra 4MiB SPI flash memory
- RGB User LED
- Reset button
- Native USB port

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

.. zephyr:board-supported-hw::

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

The `Serpente documentation`_ has detailed information about the board
including `pinouts`_ and the `schematic`_.

System Clock
============

The SAMD21 MCU is configured to use the 8MHz internal oscillator
with the on-chip PLL generating the 48 MHz system clock.

USB Device Port
===============

The SAMD21 MCU has a USB device port that can be used to communicate
with a host PC.  See the :zephyr:code-sample-category:`usb` sample applications for
more, such as the :zephyr:code-sample:`usb-cdc-acm` sample which prints "Hello World!"
to the host PC.

Programming and Debugging
=========================

.. zephyr:board-supported-runners::

The Serpente ships the BOSSA compatible UF2 bootloader. The bootloader
can be entered by quickly tapping the reset button twice.

Flashing
========

#. Build the Zephyr kernel and the :zephyr:code-sample:`blinky` sample application:

   .. zephyr-app-commands::
      :zephyr-app: samples/basic/blinky
      :board: serpente
      :goals: build
      :compact:

#. Connect the Serpente to your host computer using USB


#. Tap the reset button twice quickly to enter bootloader mode

#. Flash the image:

   .. zephyr-app-commands::
      :zephyr-app: samples/basic/blinky
      :board: serpente
      :goals: flash
      :compact:

   You should see the User LED blink.

References
**********

.. target-notes::

.. _Serpente documentation:
    https://www.solder.party/docs/serpente/r2/

.. _pinouts:
    https://www.solder.party/docs/serpente/r2/pinout/

.. _schematic:
    https://www.solder.party/docs/serpente/r2/downloads/