171 lines
5.3 KiB
ReStructuredText
171 lines
5.3 KiB
ReStructuredText
.. _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/arm/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 :ref:`usb-samples` sample applications for
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more, such as the :ref:`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 :ref:`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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