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2cd51a33ce
This provides a better error message when building with CMake and forgetting ZEPHYR_BASE or not registering Zephyr in the CMake package registry. See parent commit for more details (split from parent for better readability). Signed-off-by: Marc Herbert <marc.herbert@intel.com> |
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| CMakeLists.txt | ||
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| nrf52-bindings.h | ||
| prj.conf | ||
| README.rst | ||
| sample.yaml | ||
.. _led_ws2812_sample: WS2812 Sample Application ######################### Overview ******** This sample application demonstrates basic usage of the WS2812 LED strip driver, for controlling LED strips using WS2812, WS2812b, SK6812, and compatible driver chips. Requirements ************ .. _NeoPixel Ring 12 from AdaFruit: https://www.adafruit.com/product/1643 .. _74AHCT125: https://cdn-shop.adafruit.com/datasheets/74AHC125.pdf - LED strip using WS2812 or compatible, such as the `NeoPixel Ring 12 from AdaFruit`_. - Note that 5V communications may require a level translator, such as the `74AHCT125`_. - LED power strip supply. It's fine to power the LED strip off of your board's IO voltage level even if that's below 5V; the LEDs will simply be dimmer in this case. Wiring ****** #. Ensure your Zephyr board, and the LED strip share a common ground. #. Connect the LED strip control pin (either SPI MOSI or GPIO) from your board to the data input pin of the first WS2812 IC in the strip. #. Power the LED strip at an I/O level compatible with the control pin signals. Building and Running ******************** .. _blog post on WS2812 timing: https://wp.josh.com/2014/05/13/ws2812-neopixels-are-not-so-finicky-once-you-get-to-know-them/ This sample's source directory is :zephyr_file:`samples/drivers/led_ws2812/`. To make sure the sample is set up properly for building, you must: - select the correct WS2812 driver backend for your SoC. This currently should be :option:`CONFIG_WS2812_STRIP_SPI` unless you are using an nRF51 SoC, in which case it will be :option:`CONFIG_WS2812_STRIP_GPIO`. - create a ``led-strip`` :ref:`devicetree alias <dt-alias-chosen>`, which refers to a node in your :ref:`devicetree <dt-guide>` with a ``worldsemi,ws2812-spi`` or ``worldsemi,ws2812-gpio`` compatible. The node must be properly configured for the driver backend (SPI or GPIO) and daisy chain length (number of WS2812 chips). For example devicetree configurations for each compatible, see :zephyr_file:`samples/drivers/led_ws2812/boards/nrf52dk_nrf52832.overlay` and :zephyr_file:`samples/drivers/led_ws2812/boards/nrf51dk_nrf51422.overlay`. Some boards are already supported out of the box; see the :file:`boards` directory for this sample for details. Then build and flash the application: .. zephyr-app-commands:: :zephyr-app: samples/drivers/led_ws2812 :board: <board> :goals: flash :compact: When you connect to your board's serial console, you should see the following output: .. code-block:: none ***** Booting Zephyr OS build v2.1.0-rc1-191-gd2466cdaf045 ***** [00:00:00.005,920] <inf> main: Found LED strip device WS2812 [00:00:00.005,950] <inf> main: Displaying pattern on strip References ********** - `RGB LED strips: an overview <http://nut-bolt.nl/2012/rgb-led-strips/>`_ - `74AHCT125 datasheet <https://cdn-shop.adafruit.com/datasheets/74AHC125.pdf>`_ - An excellent `blog post on WS2812 timing`_.