2017-10-20 03:28:25 +08:00
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.. _led_lpd8806_sample:
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LPD880x Sample Application
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##########################
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Overview
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********
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This sample application demonstrates basic usage of the lpd880x LED
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strip driver, for controlling LED strips using LPD8803, LPD8806, and
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compatible driver chips.
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Requirements
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************
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.. _these strips from AdaFruit: https://www.adafruit.com/product/306
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.. _74AHCT125: https://cdn-shop.adafruit.com/datasheets/74AHC125.pdf
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- LED strip using LPD8806 or compatible, such as `these strips from AdaFruit`_.
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- Zephyr board with SPI master driver. SPI communications must use 5V
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2017-11-16 00:37:56 +08:00
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signaling, which may require a level translator, such as the
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2017-10-20 03:28:25 +08:00
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`74AHCT125`_.
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- 5V power supply.
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Wiring
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******
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#. Ensure your Zephyr board, the 5V power supply, and the LED strip
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share a common ground.
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#. Connect the MOSI pin of your board's SPI master to the data input
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pin of the first LPD8806 IC in the strip.
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#. Connect the SCLK pin of your board's SPI master to the clock input
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pin of the first LPD8806 IC in the strip.
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#. Connect the 5V power supply pin to the 5V input of the LED strip.
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Building and Running
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********************
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The sample application is located at ``samples/drivers/led_lpd8806/``
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in the Zephyr source tree.
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Before running the application, configure it as follows.
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#. Configure your board's SPI master in a configuration file under
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``boards/`` in the sample directory.
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To provide additional configuration for some particular board,
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create a ``boards/YOUR_BOARD_NAME.conf`` file in the application
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directory. It will be merged into the application configuration.
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In this file, you must ensure that the SPI peripheral you want to
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use for this demo is enabled, and that its name is "lpd8806_spi".
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See ``boards/96b_carbon.conf`` for an example, and refer to your
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board's configuration options to set up your desired SPI master.
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#. Set the number of LEDs in your strip in the application sources.
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This is determined by the macro ``STRIP_NUM_LEDS`` in the file
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``src/main.c``. The value in the file was chosen to work with one
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meter of the AdaFruit strip.
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Then build and flash the application:
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2017-11-12 17:13:30 +08:00
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.. zephyr-app-commands::
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:zephyr-app: samples/drivers/led_lpd8806
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:board: <board>
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:goals: flash
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:compact:
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2017-10-20 03:28:25 +08:00
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Refer to your :ref:`board's documentation <boards>` for alternative
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flash instructions if your board doesn't support the ``flash`` target.
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When you connect to your board's serial console, you should see the
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following output:
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.. code-block:: none
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***** BOOTING ZEPHYR OS v1.9.99 *****
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[general] [INF] main: Found SPI device lpd8806_spi
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[general] [INF] main: Found LED strip device lpd880x_strip
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[general] [INF] main: Displaying pattern on strip
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References
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**********
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- `LPD8806 datasheet <https://cdn-shop.adafruit.com/datasheets/lpd8806+english.pdf>`_
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- `RGB LED strips: an overview <http://nut-bolt.nl/2012/rgb-led-strips/>`_
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- `74AHCT125 datasheet <https://cdn-shop.adafruit.com/datasheets/74AHC125.pdf>`_
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