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Arduino Zero

Support for the Arduino Zero board.

Support for the Arduino Zero board.


The Arduino Zero is a board by Arduino/Genuino featuring a ATSAMD21G18A. The SAMD21 is a ARM Cortex-M0+ micro-controller. It has 256KiB of flash memory and 32KiB of RAM.

This board is available here.




Family ARM Cortex-M0+
Vendor Atmel
Flash 256KiB
Frequency up to 48MHz
FPU no
Timers 6 (1x 16-bit, 2x 24-bit, 3x 32-bit)
ADCs 6x 12-bit channels)
SPIs max 6 (see UART)
I2Cs max 6 (see UART)
Vcc 1.8V - 3.6V
Datasheet Datasheet

User Interface

1 LED:

Device PIN

Implementation Status

Notice that the initial support for the Arduino Zero was based on samr21-xpro and Sodaq Autonomo.

Device ID Supported Comments
MCU samd21 partly Energy saving modes not fully utilized
Low-level driver GPIO yes
PWM to be tested
UART yes two UARTs
I2C yes
SPI yes
ADC not implemented
USB no
RTT yes
RTC yes
RNG no no HW module
Timer yes

Detailed information on the board can be found on the official web page.

Flashing the device

The standard method for flashing RIOT to the Arduino Zero is using OpenOCD. For this to work properly, you have to make sure to use a very recent version of OpenOCD. Arduino-IDE comes with openocd v0.9.0 which is known to work. Also Ubuntu 16.04 has openocd v0.9.0.

Refer to https://github.com/RIOT-OS/RIOT/wiki/OpenOCD for building OpenOCD and make sure "cmsis-dap" and "hidapi-libusb" are enabled.

Supported Toolchains

To build software for the Arduino Zero board we strongly recommend the usage of the GNU Tools for ARM Embedded Processors toolchain.

Known Issues / Problems

Stack sizes

The default stack sizes have not been tuned properly yet. If in doubt why your application crashes try increasing the default stack sizes and use ps to find out how much stack is being used. Tracked in https://github.com/RIOT-OS/RIOT/issues/2228