//////////
//
// Arduino interface for the use of APA-102 operated LEDs
// Uses Adalight protocol and is compatible with Boblight, Prismatik etc
// "Magic Word" for synchronisation is 'Ada' followed by LED High, Low and Checksum
//
//////////
 
#include "FastLED.h"
 
// Define the number of LEDs
#define NUM_LEDS 114
 
// Define SPI Pin. This version is using a 32u4 so pinout is different. Workst with pins 11 & 13 on the Uno.
#define DATA_PIN 16
#define CLOCK_PIN 15
 
// Baudrate, higher rate allows faster refresh rate and more LEDs (defined in /etc/boblight.conf)
//#define serialRate 115200
 
// Adalight sends a "Magic Word" (defined in /etc/boblight.conf) before sending the pixel data
uint8_t prefix[] = {'A', 'd', 'a'}, hi, lo, chk, i;
 
// initialise LED-array
CRGB leds[NUM_LEDS];
 
void setup()
{
 
  FastLED.addLeds<APA102, DATA_PIN, CLOCK_PIN, BGR>(leds, NUM_LEDS);
 
  // initial RGB flash
  LEDS.showColor(CRGB(255, 0, 0));
  delay(500);
  LEDS.showColor(CRGB(0, 255, 0));
  delay(500);
  LEDS.showColor(CRGB(0, 0, 255));
  delay(500);
  LEDS.showColor(CRGB(0, 0, 0));
 
//  Serial.begin(serialRate);
  Serial.print("Ada\n"); // Send "Magic Word" string to host
 
}
 
void loop() {
  // wait for first byte of Magic Word
  for(i = 0; i < sizeof prefix; ++i) {
//    waitLoop: while (!Serial.available()) ;;
    // Check next byte in Magic Word
    if(prefix[i] == Serial.read()) continue;
    // otherwise, start over
    i = 0;
//    goto waitLoop;
  }
 
  // Hi, Lo, Checksum
 
//  while (!Serial.available()) ;;
  hi=Serial.read();
//  while (!Serial.available()) ;;
  lo=Serial.read();
//  while (!Serial.available()) ;;
  chk=Serial.read();
 
  // if checksum does not match go back to wait
  if (chk != (hi ^ lo ^ 0x55))
  {
    i=0;
//    goto waitLoop;
  }
 
  memset(leds, 0, NUM_LEDS * sizeof(struct CRGB));
  // read the transmission data and set LED values
  for (uint8_t i = 0; i < NUM_LEDS; i++) {
    byte r, g, b;    
//    while(!Serial.available());
    r = Serial.read();
//    while(!Serial.available());
    g = Serial.read();
//    while(!Serial.available());
    b = Serial.read();
    leds[i].r = r;
    leds[i].g = g;
    leds[i].b = b;
  }
  // shows new values
 FastLED.show();
}