Arduino/Genuino Zero


The Arduino Zero is a maker-friendly development board with Atmel’s Embedded Debugger (EDBG), which provides a full debug interface without the need for additional hardware.

Arduino Zero


  • ATSAMD21G18A ARM Cortex-M0+ processor at 48 MHz
  • 32.768 kHz crystal oscillator
  • 256 KiB flash memory and 32 KiB of RAM
  • 3 user LEDs
  • One reset button
  • On-board USB based EDBG unit with serial console
  • Native USB port

Supported Features

The arduino_zero board configuration supports the following hardware features:

Interface Controller Driver/Component
NVIC on-chip nested vector interrupt controller
Flash on-chip Can be used with NFFS to store files
SYSTICK on-chip systick
WDT on-chip Watchdog
GPIO on-chip I/O ports
USART on-chip Serial ports
SPI on-chip Serial Peripheral Interface ports
USB on-chip USB device

Other hardware features are not currently supported by Zephyr.

The default configuration can be found in the Kconfig boards/arm/arduino_zero/arduino_zero_defconfig.

Connections and IOs

The Arduino store [1] has detailed information about board connections. Download the Arduino Zero Schematic [2] 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. One of the USARTs (SERCOM5) is connected to the onboard Atmel Embedded Debugger (EDBG). SERCOM0 is available on the D0/D1 pins.

SPI Port

The SAMD21 MCU has 6 SERCOM based SPIs. On the Arduino Zero, SERCOM4 is available on the 6 pin connector at the edge of the board.

USB Device Port

The SAMD21 MCU has a USB device port that can be used to communicate with a host PC. See the USB Samples sample applications for more, such as the USB CDC ACM Sample Application sample which sets up a virtual serial port that echos characters back to the host PC.

Programming and Debugging

The Arduino Zero comes with a Atmel Embedded Debugger (EDBG). This provides a debug interface to the SAMD21 chip and is supported by OpenOCD.


  1. Build the Zephyr kernel and the Hello World sample application:

    # On Linux/macOS
    cd $ZEPHYR_BASE/samples/hello_world
    mkdir build && cd build
    # On Windows
    cd %ZEPHYR_BASE%\samples\hello_world
    mkdir build & cd build
    cmake -GNinja -DBOARD=arduino_zero ..
  2. Connect the Arduino Zero to your host computer using the USB debug port.

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

    $ 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
  4. To flash an image:

    # On Linux/macOS
    cd $ZEPHYR_BASE/samples/hello_world
    mkdir build && cd build
    # On Windows
    cd %ZEPHYR_BASE%\samples\hello_world
    mkdir build & cd build
    cmake -GNinja -DBOARD=arduino_zero ..
    ninja flash

    You should see “Hello World! arm” in your terminal.