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https://github.com/zephyrproject-rtos/zephyr
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The Adafruit Feather M4 Express is a compact, lightweight ARM development board with an onboard mini NeoPixel, 2 MiB of SPI flash, charging status indicator and user LEDs, USB connector, 21 GPIO pins and a small prototyping area. Signed-off-by: Teresa Zepeda Ventura <teresa.zvent@gmail.com>
202 lines
6.6 KiB
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202 lines
6.6 KiB
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.. zephyr:board:: adafruit_feather_m4_express
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Overview
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The Adafruit Feather M4 Express is a compact, lightweight
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ARM development board with an onboard mini NeoPixel, 2 MiB
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of SPI flash, charging status indicator and user LEDs, USB
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connector, 21 GPIO pins and a small prototyping area.
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Hardware
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- ATSAMD51J19A ARM Cortex-M4 processor at 120 MHz
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- 512 KiB of flash memory and 192 KiB of RAM
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- 2 MiB of SPI flash
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- Internal trimmed 8 MHz oscillator
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- A user LED
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- An RGB NeoPixel 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_feather_m4_express`` board target supports the following
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hardware features:
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+-----------+------------+------------------------------------------+
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| Interface | Controller | Driver/Component |
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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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| 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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| TRNG | on-chip | True Random Number Generator |
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+-----------+------------+------------------------------------------+
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| HWINFO | on-chip | Unique 128 bit serial number |
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+-----------+------------+------------------------------------------+
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| RTC | on-chip | Real-Time Counter |
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+-----------+------------+------------------------------------------+
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| USB | on-chip | USB device |
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+-----------+------------+------------------------------------------+
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| WDT | on-chip | Watchdog Timer |
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+-----------+------------+------------------------------------------+
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| PWM | on-chip | PWM |
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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/feather_m4_express/adafruit_feather_m4_express_defconfig`.
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Zephyr can use the default Cortex-M SYSTICK timer or the SAM0 specific RTC.
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To use the RTC, set :code:`CONFIG_CORTEX_M_SYSTICK=n` and set
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:code:`CONFIG_SYS_CLOCK_TICKS_PER_SEC` to no more than 32 kHZ divided by 7,
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i.e. no more than 4500.
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Connections and IOs
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===================
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The `Adafruit Learning System`_ 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 SAMD51 MCU is configured to use the 32 kHz internal oscillator
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with the on-chip PLL generating the 120 MHz system clock.
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Serial Port
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===========
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The SAMD51 MCU has 6 SERCOM based USARTs. On the Feather, SERCOM5 is
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the Zephyr console and is available on pins 0 (RX) and 1 (TX).
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SPI Port
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========
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The SAMD51 MCU has 6 SERCOM based SPIs. On the Feather, SERCOM1 can be put
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into SPI mode and used to connect to devices over the SCK (SCLK), MO (MOSI), and
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MI (MISO) pins.
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PWM
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===
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The SAMD51 has three PWM generators with up to six channels each. :code:`TCC_0`
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has a resolution of 24 bits and all other generators are 16 bit. :code:`TCC_1`
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pin 2 is mapped to PA18 (D7) and pin 3 is mapped to PA19 (D9).
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USB Device Port
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===============
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The SAMD51 MCU has a USB device port that can be used to communicate
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with a host PC. See the :ref:`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 Feather ships with a 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 :kconfig:option:`CONFIG_USB_CDC_ACM` is enabled then the
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bootloader 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_feather_m4_express
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:goals: build
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:compact:
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#. Connect the feather 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/ttyUSB0`. For example:
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.. code-block:: console
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$ minicom -D /dev/ttyUSB0 -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_feather_m4_express
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:goals: flash
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:compact:
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You should see "Hello World! adafruit_feather_m4_express" in your terminal.
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Debugging
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=========
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In addition to the built-in bootloader, the Feather can be flashed and
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debugged using a SWD probe such as the Segger J-Link.
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#. Connect the board to the probe by connecting the :code:`SWCLK`,
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:code:`SWDIO`, :code:`RESET`, :code:`GND`, and :code:`3V3` pins on the
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Feather to the :code:`SWCLK`, :code:`SWDIO`, :code:`RESET`, :code:`GND`,
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and :code:`VTref` pins on the `J-Link`_.
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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_feather_m4_express
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:goals: flash
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:flash-args: -r openocd
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:compact:
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#. Start debugging:
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.. zephyr-app-commands::
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:zephyr-app: samples/hello_world
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:board: adafruit_feather_m4_express
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:goals: debug
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:compact:
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References
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**********
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.. target-notes::
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.. _Adafruit Learning System:
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https://learn.adafruit.com/adafruit-feather-m4-express-atsamd51
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.. _pinouts:
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https://learn.adafruit.com/adafruit-feather-m4-express-atsamd51/pinouts
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.. _schematic:
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https://learn.adafruit.com/adafruit-feather-m4-express-atsamd51/downloads
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.. _J-Link:
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https://www.segger.com/products/debug-probes/j-link/technology/interface-description/
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