.. zephyr:board:: sparkfun_samd21_breakout

Overview

The SparkFun SAMD21 dev breakout board is an arduino form factor development board. Designed to be a more powerful arduino. It shares the arduino form factor and gpio footprint. Based on the ATSAMD21G18 MCU, it runs a 32-Bit Arm Cortex-M0+ at up to 48MHz. More information can be found on the SAMD21 dev breakout specification website_.

Hardware

ATSAMD21G18 32-bit/48MHz ARM Cortex-M0+
256KB Flash Memory
32KB SRAM
32KB of EEPROM (emulated in Flash)
30 GPIO Count with Arduino R3 footprint
6x Configurable SERCOM ports
- USART with full-duplex and single-wire half-duplex configuration
- I2C up to 3.4 MHz
- SPI
- LIN client
One 12-bit, 350ksps Analog-to-Digital Converter (ADC) with up to 20 channels
- Differential and single-ended input
- 1/2x to 16x programmable gain stage
- Automatic offset and gain error compensation
- Oversampling and decimation in hardware to support 13-bit, 14-bit, 15-bit, or 16-bit resolution
One two-channel Inter-IC Sound (I2S) interface
32-bit Real Time Counter (RTC) with clock/calendar function
Watchdog Timer (WDT)
CRC-32 generator
One full-speed (12 Mbps) Universal Serial Bus (USB) 2.0 interface
- Embedded host and device function
- Eight endpoint

Supported Features

.. zephyr:board-supported-hw::

Connections and IOs

LED

Led0 (blue) = D13

Serial IO

sparkfun_spi = sercom4
sparkfun_i2c = sercom3
sparkfun_serial = sercom0
sparkfun_dac = dac0
sparkfun_adc = adc

Programming and Debugging

.. zephyr:board-supported-runners::

Applications for the sparkfun_samd21_breakout/samd21g18a board target can be built, flashed, and debugged in the usual way. See :ref:build_an_application and :ref:application_run for more details on building and running.

Flashing

To enter flash mode, connect the board via the micro USB to the host, press the reset button twice. The onboard blue led should slowly fade, indicating flash mode.

Flashing Application

This board utilizes the UF2 bootloader, which flashes firmware via uploaded a file to board via mass-storage device. See uf2-samdx1 bootloader info_.

Flashing Bootloader

If flashing the bootloader you can use a Jeff Probe/Black Magic Debugger to connect via SWD. Note this can also be used to recover a bricked board. Bootloader source code repo is available at: uf2-samdx1 bootloader repo_.

Build bootloader for sparkfun samd21 dev board:

.. code-block:: console

git clone https://github.com/adafruit/uf2-samdx1 cd uf2-samdx1 make BOARD=sparkfun-samd21-dev

Place commands to flash bootloader into a gdb_init file:

.. code-block:: console

target extended-remote /dev/ttyACM<num> # check in dmesg monitor swdp_scan # make sure this works too, cable could be upside down attach 1 load

Connect the debug probe and run:

.. code-block:: console

Run gdb with your gdb_init script:

arm-none-eabi-gdb bootloader-sparkfun-samd21-dev-<bootloader-version>.elf -x gdb_init

Debugging

Using the Jeff Probe/Black Magic Debugger, you can connect SWD and run gdb through the serial connection. See above for example instructions for flashing the bootloader. Otherwise, use west to debug.

Debug with west:

.. code-block:: console

west debug -r blackmagicprobe

References

.. target-notes::

.. _SAMD21 dev breakout specification website: https://www.sparkfun.com/sparkfun-samd21-dev-breakout.html .. _uf2-samdx1 bootloader repo: https://github.com/adafruit/uf2-samdx1 .. _uf2-samdx1 bootloader info: https://learn.sparkfun.com/tutorials/arm-programming/bootloaders