LPD880x Sample Application

Overview

This sample application demonstrates basic usage of the lpd880x LED strip driver, for controlling LED strips using LPD8803, LPD8806, and compatible driver chips.

Requirements

  • LED strip using LPD8806 or compatible, such as these strips from AdaFruit.
  • Zephyr board with SPI master driver. SPI communications must use 5V signaling, which may require a level translator, such as the 74AHCT125.
  • 5V power supply.

Wiring

  1. Ensure your Zephyr board, the 5V power supply, and the LED strip share a common ground.
  2. Connect the MOSI pin of your board’s SPI master to the data input pin of the first LPD8806 IC in the strip.
  3. Connect the SCLK pin of your board’s SPI master to the clock input pin of the first LPD8806 IC in the strip.
  4. Connect the 5V power supply pin to the 5V input of the LED strip.

Building and Running

The sample application is located at samples/drivers/led_lpd8806/ in the Zephyr source tree.

Before running the application, configure it as follows.

  1. Configure your board’s SPI master in a configuration file under boards/ in the sample directory.

    To provide additional configuration for some particular board, create a boards/YOUR_BOARD_NAME.conf file in the application directory. It will be merged into the application configuration.

    In this file, you must ensure that the SPI peripheral you want to use for this demo is enabled, and that its name is “lpd8806_spi”. See boards/96b_carbon.conf for an example, and refer to your board’s configuration options to set up your desired SPI master.

  2. Set the number of LEDs in your strip in the application sources. This is determined by the macro STRIP_NUM_LEDS in the file src/main.c. The value in the file was chosen to work with one meter of the AdaFruit strip.

Then build and flash the application:

west build -b <board> samples/drivers/led_lpd8806
west flash

Refer to your board’s documentation for alternative flash instructions if your board doesn’t support the flash target.

When you connect to your board’s serial console, you should see the following output:

***** BOOTING ZEPHYR OS v1.9.99 *****
[general] [INF] main: Found SPI device lpd8806_spi
[general] [INF] main: Found LED strip device lpd880x_strip
[general] [INF] main: Displaying pattern on strip