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Overview

boards/arduino/mkrzero/doc/index.rst

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.. zephyr:board:: arduino_mkrzero

Overview

The Arduino MKR Zero built with smaller MKR form factor and powered by Atmel's SAMD21 MCU. This board come with microSD card holder that allows you to play with music files with no extra hardware.

Hardware

  • ATSAMD21G18A ARM Cortex-M0+ processor at 48 MHz
  • 32.768 kHz crystal oscillator
  • 256 KiB flash memory and 32 KiB of RAM
  • One user LEDs
  • One reset button
  • microSD card slot
  • ATECC508A secure element

Supported Features

.. zephyr:board-supported-hw::

Connections and IOs

The Arduino store_ has detailed information about board connections. Download the Arduino MKR Zero Schematic_ for more detail.

System Clock

The SAMD21 MCU is configured to use the 32.768 kHz external oscillator with the on-chip PLL generating the 48 MHz system clock. The internal APB and GCLK unit are set up in the same way as the upstream Arduino libraries.

Serial Port

The SAMD21 MCU has 6 SERCOM based USARTs. SERCOM5 is available on pins 13(PA23) and 14(PA22).

PWM

The SAMD21 MCU has 3 TCC based PWM units with up to 4 outputs each and a period of 24 bits or 16 bits.

SPI Port

The SAMD21 MCU has 6 SERCOM based SPIs. On the Arduino MKR Zero, SERCOM1 is available on pin 8, 9, and 10. SERCOM2 connect to microSD card slot as SPI interface.

I2C Port

The SAMD21 MCU has 6 SERCOM based I2Cs. SERCOM0 is available on pin 11(PA08) and 12(PA09). This I2C bus also available as ESLOV(JST SH 5pin) socket. ATECC508A secure element is connect to this I2C bus.

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 sets up a virtual serial port that echos characters back to the host PC.

DAC

The SAMD21 MCU has a single channel DAC with 10 bits of resolution. On the Arduino MKR Zero, the DAC is available on pin A0.

Programming and Debugging

.. zephyr:board-supported-runners::

The Arduino MKR Zero ships the BOSSA compatible bootloader. The bootloader can be entered by quickly tapping the reset button twice.

Flashing

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

.. zephyr-app-commands:: :zephyr-app: samples/hello_world :board: arduino_mkrzero :goals: build :compact:

#. Connect the MKR Zero to your host computer using USB

#. Connect a 3.3 V USB to serial adapter to the board and to the host. See the Serial Port_ section above for the board's pin connections.

#. Run your favorite terminal program to listen for output. Under Linux the terminal should be :code:/dev/ttyACM0. For example:

.. code-block:: console

  $ minicom -D /dev/ttyACM0 -o

The -o option tells minicom not to send the modem initialization string. Connection should be configured as follows:

  • Speed: 115200
  • Data: 8 bits
  • Parity: None
  • Stop bits: 1

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

#. Flash the image:

.. zephyr-app-commands:: :zephyr-app: samples/hello_world :board: arduino_mkrzero :goals: flash :compact:

You should see "Hello World! arduino_mkrzero" in your terminal.

References

.. target-notes::

.. _Arduino Store: https://store.arduino.cc/collections/boards/products/arduino-mkr-zero-i2s-bus-sd-for-sound-music-digital-audio-data

.. _Arduino MKR Zero Schematic: https://www.arduino.cc/en/uploads/Main/ArduinoMKRZero-schematic.pdf