// hobbyprojects.com
// apa102_rgb_BLUE_LED_Blink.ino

int apa102Clock = 7;
int apa102Data = 8;

int i;

//---------------------------

void setup() {

  pinMode(apa102Data,OUTPUT);  
  pinMode(apa102Clock,OUTPUT); 

}

//---------------------------

void loop()
{
  // Start Frame 
  spiWrite(0x00);   
  spiWrite(0x00);
  spiWrite(0x00);
  spiWrite(0x00);

  // LED frame
  spiWrite(0b11100011);   // The first three bits(MSB) of the LED frame should be ‘1’. The next 5 bits(LSB) are brightness value (0–31)
  spiWrite(0b11111111);   // blue LED ON)
  spiWrite(0b00000000);   // green LED OFF)
  spiWrite(0b00000000);   // red LED OFF)

  // End frame
  spiWrite(0b11111111);

  delay(500);

  // LED OFF
  
  // Start Frame 
  spiWrite(0x00);
  spiWrite(0x00);
  spiWrite(0x00);
  spiWrite(0x00);

  //LED frame
  spiWrite(0b11100000);  // The first three bits(MSB) of the LED frame should be ‘1’. The next 5 bits(LSB) are brightness value (0–31)
  spiWrite(0b00000000);  // blue LED OFF)
  spiWrite(0b00000000);  // green LED OFF)
  spiWrite(0b00000000);  // red LED OFF)

  // End frame
  spiWrite(0b11111111); 

  delay(500);
}


//===========================================================================


void spiWrite(uint8_t c) {
  uint8_t i;
  for (i=0; i<8 ;i++)
  {
    if (!(c&0x80)) {
      digitalWrite(apa102Data, LOW);
    } else {
      digitalWrite(apa102Data, HIGH);
    }     
  
      digitalWrite(apa102Clock, HIGH);

  c <<= 1;
  
      digitalWrite(apa102Clock, LOW);
  }
      digitalWrite(apa102Data, HIGH);
}