| .. _adafruit_trinket_m0: |
| |
| Adafruit Trinket M0 |
| ################### |
| |
| Overview |
| ******** |
| |
| The Adafruit Trinket M0 is a tiny (27 mm x 15 mm) ARM development |
| board with an onboard RGB LED, USB port, and range of I/O broken out |
| onto 5 pins. |
| |
| .. image:: img/adafruit_trinket_m0.png |
| :width: 500px |
| :align: center |
| :alt: Adafruit Trinket M0 |
| |
| Hardware |
| ******** |
| |
| - ATSAMD21E18A ARM Cortex-M0+ processor at 48 MHz |
| - 256 KiB flash memory and 32 KiB of RAM |
| - Internal trimmed 8 MHz oscillator |
| - A user LED |
| - An RGB DotStar LED |
| - Native USB port |
| - One reset button |
| |
| Supported Features |
| ================== |
| |
| The adafruit_trinket_m0 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 file |
| :zephyr_file:`boards/arm/adafruit_trinket_m0/adafruit_trinket_m0_defconfig`. |
| |
| Connections and IOs |
| =================== |
| |
| The `Adafruit Trinket M0 Learn site`_ has detailed information about |
| the board including `pinouts`_ and the `schematic`_. |
| |
| System Clock |
| ============ |
| |
| The SAMD21 MCU is configured to use the 8 MHz internal 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. On the Trinket, SERCOM0 is |
| the Zephyr console and is available on pins 3 (RX) and 4 (TX). |
| SERCOM2 is available on pins 2 (RX) and 0 (TX). |
| |
| SPI Port |
| ======== |
| |
| The SAMD21 MCU has 6 SERCOM based SPIs. On the Trinket, SERCOM1 is |
| used to drive the DotStar RGB LED. SERCOM0 can be put into SPI mode |
| and used to connect to devices over pin 2 (MISO), pin 4 (MOSI), and |
| pin 3 (SCK). |
| |
| 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 :ref:`usb_cdc-acm` sample which sets up a virtual |
| serial port that echos characters back to the host PC. |
| |
| Programming and Debugging |
| ************************* |
| |
| The Trinket M0 ships the BOSSA compatible UF2 bootloader. The |
| bootloader can be entered by quickly tapping the reset button twice. |
| |
| Flashing |
| ======== |
| |
| #. Build the Zephyr kernel and the :ref:`hello_world` sample application: |
| |
| .. zephyr-app-commands:: |
| :zephyr-app: samples/hello_world |
| :board: adafruit_trinket_m0 |
| :goals: build |
| :compact: |
| |
| #. Connect the Trinket M0 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: adafruit_trinket_m0 |
| :goals: flash |
| :compact: |
| |
| You should see "Hello World! arm" in your terminal. |
| |
| References |
| ********** |
| |
| .. target-notes:: |
| |
| .. _Adafruit Trinket M0 Learn site: |
| https://learn.adafruit.com/adafruit-trinket-m0-circuitpython-arduino |
| |
| .. _pinouts: |
| https://learn.adafruit.com/assets/49778 |
| |
| .. _schematic: |
| https://learn.adafruit.com/assets/45723 |