| .. _seeeduino_xiao: |
| |
| Seeeduino XIAO |
| ############## |
| |
| Overview |
| ******** |
| |
| The Seeeduino XIAO is a tiny (20 mm x 17.5 mm) ARM development |
| board with onboard LEDs, USB port, and range of I/O broken out |
| onto 14 pins. |
| |
| .. image:: img/seeeduino_xiao.jpg |
| :align: center |
| :alt: Seeeduino XIAO |
| |
| Hardware |
| ******** |
| |
| - ATSAMD21G18A ARM Cortex-M0+ processor at 48 MHz |
| - 256 KiB flash memory and 32 KiB of RAM |
| - Three user LEDs |
| - Native USB port |
| |
| Supported Features |
| ================== |
| |
| The seeeduino_xiao board configuration supports the following hardware |
| features: |
| |
| +-----------+------------+------------------------------------------+ |
| | Interface | Controller | Driver/Component | |
| +===========+============+==========================================+ |
| | DMA | on-chip | Direct memory access | |
| +-----------+------------+------------------------------------------+ |
| | DAC | on-chip | Digital to analogue converter | |
| +-----------+------------+------------------------------------------+ |
| | Flash | on-chip | Can be used with LittleFS to store files | |
| +-----------+------------+------------------------------------------+ |
| | GPIO | on-chip | I/O ports | |
| +-----------+------------+------------------------------------------+ |
| | HWINFO | on-chip | Hardware info | |
| +-----------+------------+------------------------------------------+ |
| | I2C | on-chip | Inter-Integrated Circuit | |
| +-----------+------------+------------------------------------------+ |
| | NVIC | on-chip | nested vector interrupt controller | |
| +-----------+------------+------------------------------------------+ |
| | SPI | on-chip | Serial Peripheral Interface ports | |
| +-----------+------------+------------------------------------------+ |
| | SYSTICK | on-chip | systick | |
| +-----------+------------+------------------------------------------+ |
| | USART | on-chip | Serial ports | |
| +-----------+------------+------------------------------------------+ |
| | USB | on-chip | USB device | |
| +-----------+------------+------------------------------------------+ |
| | WDT | on-chip | Watchdog | |
| +-----------+------------+------------------------------------------+ |
| |
| Other hardware features are not currently supported by Zephyr. |
| |
| The default configuration can be found in the Kconfig file |
| :zephyr_file:`boards/seeed/seeeduino_xiao/seeeduino_xiao_defconfig`. |
| |
| Connections and IOs |
| =================== |
| |
| The `Seeeduino XIAO wiki`_ has detailed information about |
| the board including `pinouts`_ and the `schematic`_. |
| |
| System Clock |
| ============ |
| |
| The SAMD21 MCU is configured to use the 32 kHz external crystal |
| 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. |
| |
| SPI Port |
| ======== |
| |
| The SAMD21 MCU has 6 SERCOM based SPIs. On the XIAO, SERCOM0 can be put |
| into SPI mode and used to connect to devices over pin 9 (MISO), pin 10 |
| (MOSI), and pin 8 (SCK). |
| |
| I2C Port |
| ======== |
| |
| The SAMD21 MCU has 6 SERCOM based USARTs. On the XIAO, SERCOM2 is available on |
| pin 4 (SDA) and pin 5 (SCL). |
| |
| Serial Port |
| =========== |
| |
| The SAMD21 MCU has 6 SERCOM based USARTs. On the XIAO, SERCOM4 is |
| the Zephyr console and is available on pins 7 (RX) and 6 (TX). |
| |
| USB Device Port |
| =============== |
| |
| The SAMD21 MCU has a USB device port that can be used to communicate |
| with a host PC. See the :ref:`usb-samples` 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 XIAO, the DAC is available on pin 0. |
| |
| Programming and Debugging |
| ************************* |
| |
| The XIAO ships the BOSSA compatible UF2 bootloader. The bootloader can be |
| entered by shorting the RST and GND pads twice. |
| |
| Additionally, if :code:`CONFIG_USB_CDC_ACM` is enabled then the bootloader |
| will be entered automatically when you run :code:`west flash`. |
| |
| Flashing |
| ======== |
| |
| #. Build the Zephyr kernel and the :ref:`hello_world` sample application: |
| |
| .. zephyr-app-commands:: |
| :zephyr-app: samples/hello_world |
| :board: seeeduino_xiao |
| :goals: build |
| :compact: |
| |
| #. Connect the XIAO 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/ttyUSB0`. For example: |
| |
| .. code-block:: console |
| |
| $ minicom -D /dev/ttyUSB0 -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 |
| |
| #. Short the RST and GND pads twice quickly to enter bootloader mode |
| |
| #. Flash the image: |
| |
| .. zephyr-app-commands:: |
| :zephyr-app: samples/hello_world |
| :board: seeeduino_xiao |
| :goals: flash |
| :compact: |
| |
| You should see "Hello World! seeeduino_xiao" in your terminal. |
| |
| References |
| ********** |
| |
| .. target-notes:: |
| |
| .. _Seeeduino XIAO wiki: |
| https://wiki.seeedstudio.com/Seeeduino-XIAO/ |
| |
| .. _pinouts: |
| https://wiki.seeedstudio.com/Seeeduino-XIAO/#hardware-overview |
| |
| .. _schematic: |
| https://wiki.seeedstudio.com/Seeeduino-XIAO/#resourses |