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170 lines
5.3 KiB
170 lines
5.3 KiB
.. _adafruit_trinket_m0: |
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Adafruit Trinket M0 |
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################### |
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Overview |
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******** |
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The Adafruit Trinket M0 is a tiny (27 mm x 15 mm) ARM development |
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board with an onboard RGB LED, USB port, and range of I/O broken out |
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onto 5 pins. |
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.. image:: img/adafruit_trinket_m0.jpg |
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:align: center |
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:alt: Adafruit Trinket M0 |
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Hardware |
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******** |
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- ATSAMD21E18A ARM Cortex-M0+ processor at 48 MHz |
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- 256 KiB flash memory and 32 KiB of RAM |
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- Internal trimmed 8 MHz oscillator |
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- A user LED |
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- An RGB DotStar LED |
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- Native USB port |
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- One reset button |
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Supported Features |
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================== |
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The adafruit_trinket_m0 board configuration supports the following hardware |
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features: |
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+-----------+------------+------------------------------------------+ |
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| Interface | Controller | Driver/Component | |
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+===========+============+==========================================+ |
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| NVIC | on-chip | nested vector interrupt controller | |
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+-----------+------------+------------------------------------------+ |
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| Flash | on-chip | Can be used with LittleFS to store files | |
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+-----------+------------+------------------------------------------+ |
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| SYSTICK | on-chip | systick | |
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+-----------+------------+------------------------------------------+ |
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| WDT | on-chip | Watchdog | |
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+-----------+------------+------------------------------------------+ |
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| GPIO | on-chip | I/O ports | |
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+-----------+------------+------------------------------------------+ |
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| PWM | on-chip | Pulse Width Modulation | |
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+-----------+------------+------------------------------------------+ |
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| USART | on-chip | Serial ports | |
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+-----------+------------+------------------------------------------+ |
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| SPI | on-chip | Serial Peripheral Interface ports | |
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+-----------+------------+------------------------------------------+ |
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| USB | on-chip | USB device | |
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+-----------+------------+------------------------------------------+ |
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Other hardware features are not currently supported by Zephyr. |
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The default configuration can be found in the Kconfig file |
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:zephyr_file:`boards/adafruit/trinket_m0/adafruit_trinket_m0_defconfig`. |
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Connections and IOs |
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=================== |
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The `Adafruit Trinket M0 Learn site`_ has detailed information about |
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the board including `pinouts`_ and the `schematic`_. |
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System Clock |
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============ |
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The SAMD21 MCU is configured to use the 8 MHz internal oscillator |
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with the on-chip PLL generating the 48 MHz system clock. The internal |
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APB and GCLK unit are set up in the same way as the upstream Arduino |
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libraries. |
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Serial Port |
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=========== |
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The SAMD21 MCU has 6 SERCOM based USARTs. On the Trinket, SERCOM0 is |
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the Zephyr console and is available on pins 3 (RX) and 4 (TX). |
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SERCOM2 is available on pins 2 (RX) and 0 (TX). |
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PWM |
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=== |
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The SAMD21 MCU has 3 TCC based PWM units with up to 4 outputs each and a period |
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of 24 bits or 16 bits. If :code:`CONFIG_PWM_SAM0_TCC` is enabled then LED0 is |
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driven by TCC0 instead of by GPIO. |
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SPI Port |
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======== |
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The SAMD21 MCU has 6 SERCOM based SPIs. On the Trinket, SERCOM1 is |
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used to drive the DotStar RGB LED. SERCOM0 can be put into SPI mode |
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and used to connect to devices over pin 2 (MISO), pin 4 (MOSI), and |
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pin 3 (SCK). |
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USB Device Port |
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=============== |
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The SAMD21 MCU has a USB device port that can be used to communicate |
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with a host PC. See the :zephyr:code-sample-category:`usb` sample applications for |
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more, such as the :zephyr:code-sample:`usb-cdc-acm` sample which sets up a virtual |
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serial port that echos characters back to the host PC. |
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Programming and Debugging |
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************************* |
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The Trinket M0 ships the BOSSA compatible UF2 bootloader. The |
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bootloader can be entered by quickly tapping the reset button twice. |
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Additionally, if :code:`CONFIG_USB_CDC_ACM` is enabled then the bootloader |
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will be entered automatically when you run :code:`west flash`. |
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Flashing |
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======== |
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#. Build the Zephyr kernel and the :zephyr:code-sample:`hello_world` sample application: |
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.. zephyr-app-commands:: |
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:zephyr-app: samples/hello_world |
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:board: adafruit_trinket_m0 |
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:goals: build |
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:compact: |
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#. Connect the Trinket M0 to your host computer using USB |
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#. Connect a 3.3 V USB to serial adapter to the board and to the |
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host. See the `Serial Port`_ section above for the board's pin |
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connections. |
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#. Run your favorite terminal program to listen for output. Under Linux the |
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terminal should be :code:`/dev/ttyACM0`. For example: |
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.. code-block:: console |
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$ minicom -D /dev/ttyACM0 -o |
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The -o option tells minicom not to send the modem initialization |
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string. Connection should be configured as follows: |
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- Speed: 115200 |
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- Data: 8 bits |
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- Parity: None |
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- Stop bits: 1 |
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#. Tap the reset button twice quickly to enter bootloader mode |
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#. Flash the image: |
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.. zephyr-app-commands:: |
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:zephyr-app: samples/hello_world |
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:board: adafruit_trinket_m0 |
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:goals: flash |
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:compact: |
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You should see "Hello World! adafruit_trinket_m0" in your terminal. |
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References |
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********** |
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.. target-notes:: |
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.. _Adafruit Trinket M0 Learn site: |
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https://learn.adafruit.com/adafruit-trinket-m0-circuitpython-arduino |
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.. _pinouts: |
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https://learn.adafruit.com/assets/49778 |
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.. _schematic: |
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https://learn.adafruit.com/assets/45723
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