172 lines
5.6 KiB
ReStructuredText
172 lines
5.6 KiB
ReStructuredText
.. _96b_carbon_nrf51_board:
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96Boards Carbon nRF51
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#####################
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Overview
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********
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This is the secondary nRF51822 chip on the 96Boards Carbon and provides
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Bluetooth functionality to the main STM32F401RET chip via SPI.
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.. note::
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If you're looking to reprogram the main STMicro part, see
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:ref:`96b_carbon_board`. Users should not use this configuration
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unless they want to reprogram the secondary chip which provides
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Bluetooth connectivity.
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Hardware
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********
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The 96Boards Carbon nRF51 has two external oscillators. The frequency
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of the slow clock is 32.768 kHz. The frequency of the main clock is 16
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MHz.
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See :ref:`96b_carbon_board` for other general information about the
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board; that configuration is for the same physical board, just a
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different chip.
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Supported Features
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==================
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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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| RTC | 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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| GPIO | on-chip | gpio |
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+-----------+------------+-------------------------------------+
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| FLASH | on-chip | flash |
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+-----------+------------+-------------------------------------+
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| SPIS | on-chip | SPI slave |
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+-----------+------------+-------------------------------------+
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| RADIO | on-chip | Bluetooth |
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+-----------+------------+-------------------------------------+
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The default configuration can be found in the defconfig file:
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``boards/arm/96b_carbon_nrf51/96b_carbon_nrf51_defconfig``
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Connections and IOs
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===================
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SPI
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---
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96Boards Carbon nRF51 has one SPI, which for providing Bluetooth
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communication. The default SPI mapping for Zephyr is:
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- SPI1_NSS : P0.25
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- SPI1_SCK : P0.07
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- SPI1_MISO : P0.30
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- SPI1_MOSI : P0.00
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The SWD debug pins are broken out to an external header; all other
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connected pins are to the main STM32F401RET chip.
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.. _96b_carbon_nrf51_programming:
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Programming and Debugging
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*************************
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Flashing
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========
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The 96Boards Carbon nRF51 can be flashed using an external SWD
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debugger, via the debug header labeled "BLE" on the board's
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silkscreen. The header is not populated; 0.1" male header must be
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soldered on first.
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.. figure:: img/96b_carbon_nrf51.png
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:align: center
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:alt: 96Boards Carbon nRF51 Debug
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96Boards Carbon nRF51 Debug
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The following example assumes a Zephyr binary ``zephyr.elf`` will be
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flashed to the board.
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It uses the `Black Magic Debug Probe`_ as an SWD programmer, which can
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be connected to the BLE debug header using flying leads and its 20 Pin
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JTAG Adapter Board Kit. When plugged into your host PC, the Black
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Magic Debug Probe enumerates as a USB serial device as documented on
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its `Getting started page`_.
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It also uses the GDB binary provided with the Zephyr SDK,
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``arm-zephyr-eabi-gdb``. Other GDB binaries, such as the GDB from GCC
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ARM Embedded, can be used as well.
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.. code-block:: console
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$ arm-zephyr-eabi-gdb -q zephyr.elf
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(gdb) target extended-remote /dev/ttyACM0
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Remote debugging using /dev/ttyACM0
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(gdb) monitor swdp_scan
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Target voltage: 3.3V
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Available Targets:
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No. Att Driver
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1 nRF51
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(gdb) attach 1
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Attaching to Remote target
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0xabcdef12 in ?? ()
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(gdb) load
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Debugging
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=========
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After you've flashed the chip, you can keep debugging using the same
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GDB instance. To reattach, just follow the same steps above, but don't
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run "load". You can then debug as usual with GDB. In particular, type
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"run" at the GDB prompt to restart the program you've flashed.
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As an aid to debugging, this board configuration directs a console
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output to a currently unused pin connected to the STM32F401RET. Users
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who are experienced in electronics rework can remove a resistor (R22)
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on the board and attach a wire to the nRF51822's UART output.
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.. _96b_carbon_nrf51_bluetooth:
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Providing Bluetooth to 96b_carbon
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*********************************
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This 96b_carbon_nrf51 Zephyr configuration can be used to provide
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Bluetooth functionality from the secondary nRF51822 chip to the
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primary STM32F401RE chip on the :ref:`96b_carbon_board`.
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To do this, build the ``samples/bluetooth/hci_spi/`` application
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provided with Zephyr with ``BOARD=96b_carbon_nrf51``, then flash it to
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the nRF51822 chip using the instructions :ref:`above
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<96b_carbon_nrf51_programming>`. (For instructions on how to build a
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Zephyr application, see :ref:`build_an_application`.)
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.. warning::
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Be sure to flash the hci_spi application to the nRF51822 chip and
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not to the main STM32F401RET chip. While both chips are supported
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by Zephyr, the hci_spi application providing Bluetooth support will
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only run on the nRF51822 chip.
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References
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**********
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- `Board documentation from 96Boards`_
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- `nRF51822 information from Nordic Semiconductor`_
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.. _Black Magic Debug Probe:
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https://github.com/blacksphere/blackmagic/wiki
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.. _Getting started page:
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https://github.com/blacksphere/blackmagic/wiki/Getting-Started
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.. _Board documentation from 96Boards:
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http://www.96boards.org/product/carbon/
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.. _nRF51822 information from Nordic Semiconductor:
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https://www.nordicsemi.com/eng/Products/Bluetooth-low-energy/nRF51822
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