b897415a3c
Change-Id: I35490c09e1f8132d6da088b57d13f8655b72d888 Signed-off-by: Daniel Leung <daniel.leung@intel.com> Signed-off-by: Rodrigo Caballero <rodrigo.caballero.abraham@intel.com> Signed-off-by: Anas Nashif <anas.nashif@intel.com>
157 lines
6.1 KiB
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157 lines
6.1 KiB
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.. _arduino_due:
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Board Configuration: arduino_due
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################################
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Overview
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********
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The arduino_due board configuration is used by Zephyr applications
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that run on the Arduino Due board. It provides support for the Atmel
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SAM3X8E ARM Cortex-M3 CPU and the following devices:
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* Nested Vectored Interrupt Controller (NVIC)
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* System Tick System Clock (SYSTICK)
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* Serial Port over USB (ATMEL_SAM3)
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More information about the board can be found at the `Arduino Due website`_.
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The `Atmel SAM3X8E Datasheet`_ has the information and the datasheet about
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the processor.
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Supported Features
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******************
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The arduino_due board configuration 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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| NVIC | on-chip | nested vectored |
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| | | interrupt controller |
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+--------------+------------+----------------------+
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| SYSTICK | on-chip | system clock |
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+--------------+------------+----------------------+
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| UART | on-chip | serial port |
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+--------------+------------+----------------------+
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Other hardware features are not currently supported by the Zephyr kernel.
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See `Arduino Due website`_ and `Atmel SAM3X8E Datasheet`_ for a complete
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list of Arduino Due board hardware features.
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Interrupt Controller
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====================
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There are 15 fixed exceptions including exceptions 12 (debug
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monitor) and 15 (SYSTICK) that behave more as interrupts
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than exceptions. In addition, there can be a variable number
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of IRQs. Exceptions 7-10 and 13 are reserved. They don't need
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handlers.
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A Cortex-M3/4-based board uses vectored exceptions. This
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means each exception calls a handler directly from the
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vector table.
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Handlers are provided for exceptions 1-6, 11-12, and 14-15.
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The table here identifies the handlers used for each exception.
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+------+------------+----------------+--------------------------+
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| Exc# | Name | Remarks | Used by Zephyr Kernel |
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+======+============+================+==========================+
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| 1 | Reset | | system initialization |
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+------+------------+----------------+--------------------------+
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| 2 | NMI | | system fatal error |
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+------+------------+----------------+--------------------------+
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| 3 | Hard fault | | system fatal error |
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+------+------------+----------------+--------------------------+
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| 4 | MemManage | MPU fault | system fatal error |
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+------+------------+----------------+--------------------------+
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| 5 | Bus | | system fatal error |
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+------+------------+----------------+--------------------------+
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| 6 | Usage | undefined | system fatal error |
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| | fault | instruction, | |
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| | | or switch | |
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| | | attempt to ARM | |
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| | | mode | |
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+------+------------+----------------+--------------------------+
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| 11 | SVC | | context switch and |
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| | | | software interrupts |
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+------+------------+----------------+--------------------------+
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| 12 | Debug | | system fatal error |
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| | monitor | | |
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+------+------------+----------------+--------------------------+
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| 14 | PendSV | | context switch |
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+------+------------+----------------+--------------------------+
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| 15 | SYSTICK | | system clock |
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+------+------------+----------------+--------------------------+
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.. note::
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After a reset, all exceptions have a priority of 0. Interrupts cannot run
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at priority 0 for the interrupt locking mechanism and exception handling
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to function properly.
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System Clock
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============
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Arduino Due has two external oscillators/resonators. The slow clock is
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32.768 kHz, and the main clock is 12 MHz. The processor can set up PLL to drive
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the master clock, which can be set as high as 84 MHz.
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Serial Port
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===========
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The Atmel SAM3X8E processor has a single UART that is used by the SAM-BA
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bootloader. This UART has only two wires for RX/TX and does not have flow
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control (CTS/RTS) or FIFO. The RX/TX pins are connected to the ATmega16U2,
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which provides USB-to-TTL serial function. The Zephyr console output, by
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default, is utilizing this controller.
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Flashing Arduino Due for Zephyr
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===============================
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Flashing the Zephyr kernel onto Arduino Due requires the `bossa tool`_. Note
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that the Arduino specific version is required (branch arduino on GitHub).
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The sample application hello_world is being used in this tutorial, which can
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be found in :file:`$ZEPHYR_BASE/samples/nanokernel/apps/hello_world`.
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# To build the Zephyr kernel, enter:
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.. code-block:: console
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$ cd $ZEPHYR_BASE
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$ make -C samples/nanokernel/apps/hello_world ARCH=arm BOARD=arduino_due
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# Connect the Arduino Due to your host computer using the programming port.
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# Press the Erase button for more than 220 ms.
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# Press the Reset button so the board will boot into the SAM-BA bootloader.
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# To flash the kernel onto Arduino Due, assuming the bossa tool already
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exists. Using the command line version of bossa, enter:
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.. code-block:: console
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$ bossac -p <tty_device> -e -w -v -b outdir/zephyr.bin
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Where :code:`<tty_device>` is where the Arduino Due can be found. For
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example, under Linux, :code:`<tty_device>` should be :code:`/dev/ttyACM0`.
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# Run your favorite terminal program to listen for output. For example, under
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Linux, the terminal should be :code:`/dev/ttyACM0`.
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# Press the Reset button and you should see "Hello World!" in your terminal.
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References
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==========
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.. _Arduino Due website: https://www.arduino.cc/en/Main/ArduinoBoardDue
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.. _Atmel SAM3X8E Datasheet: http://www.atmel.com/devices/sam3x8e.aspx
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.. _bossa tool: https://github.com/shumatech/BOSSA
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