text: /*
   * Copyright (C) 2017 Freie Universität Berlin
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  /**
   * @ingroup     tests
   * @{
   *
   * @file
   * @brief       Test application for the APA102 LED strip driver
   *
   * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
   *
   * @}
   */
  
  #include <string.h>
  #include <stdio.h>
  #include <stdint.h>
  
  #include "xtimer.h"
  #include "color.h"
  
  #include "apa102.h"
  #include "apa102_params.h"
  
  /**
   * @brief   Switch to the next LED every 10ms
   */
  #define STEP        (200 * US_PER_MS)
  
  /**
   * @brief   Interval for dimming colors
   */
  #define DIM         (100 * US_PER_MS)
  
  /**
   * @brief   Step through brightness levels (0-255) in 32 steps
   */
  #define BSTEP       (8U)
  
  /**
   * @brief   Allocate the device descriptor
   */
  static apa102_t dev;
  
  /**
   * @brief   Allocate a color_rgb_t struct for each LED on the strip
   */
  static color_rgba_t leds[APA102_PARAM_LED_NUMOF];
  
  static void setcolor(int color, uint8_t alpha)
  {
      for (int i = 0; i < (int)APA102_PARAM_LED_NUMOF; i++) {
          leds[i].alpha = alpha;
          memset(&leds[i].color, 0, sizeof(color_rgb_t));
          switch (color) {
              case 0:
                  leds[i].color.r = 255;
                  break;
              case 1:
                  leds[i].color.g = 255;
                  break;
              case 2:
                  leds[i].color.b = 255;
                  break;
          }
      }
  }
  
  int main(void)
  {
      int pos = 0;
      int step = 1;
      color_hsv_t col = { 0.0, 1.0, 1.0 };
  
      puts("APA102 Test App");
  
      /* initialize all LED color values to black (off) */
      memset(leds, 0, sizeof(color_rgba_t) * APA102_PARAM_LED_NUMOF);
  
      /* initialize the driver */
      apa102_init(&dev, &apa102_params[0]);
  
      puts("Initialization done.");
  
      /* set to each red, green, and blue, and fade each color in and out */
      for (int col = 0; col <= 2; col++) {
          int i = 0;
          for (; i <= (int)UINT8_MAX; i += BSTEP) {
              setcolor(col, (uint8_t)i);
              apa102_load_rgba(&dev, leds);
              xtimer_usleep(DIM);
          }
          i -= BSTEP;
          for (; i >= 0; i -= BSTEP) {
              setcolor(col, (uint8_t)i);
              apa102_load_rgba(&dev, leds);
              xtimer_usleep(DIM);
          }
      }
  
      puts("Color Fading done");
  
      /* reset color values */
      setcolor(-1, 255);
      apa102_load_rgba(&dev, leds);
  
      xtimer_ticks32_t now = xtimer_now();
  
      while (1) {
          /* change the active color by running around the hue circle */
          col.h += 1.0;
          if (col.h > 360.0) {
              col.h = 0.0;
          }
  
          /* set the active LED to the active color value */
          memset(&leds[pos].color, 0, sizeof(color_rgb_t));
          pos += step;
          color_hsv2rgb(&col, &leds[pos].color);
  
          /* apply the values to the LED strip */
          apa102_load_rgba(&dev, leds);
  
          /* switch direction once reaching an end of the strip */
          if ((pos == (APA102_PARAM_LED_NUMOF - 1)) || (pos == 0)) {
              step *= -1;
          }
  
          xtimer_periodic_wakeup(&now, STEP);
      }
  
      return 0;
  }
  