//VARIABLES AND DEFINES HERE - NEEDED BY THE WS2812 DRIVER CODE
#define WS2812_pin 8 // only digital pin 8 works right now
#define numberOfLEDs 45// total number of RGB LEDs
byte RGB[135];//take your number of LEDs and multiply by 3

// FUNCTIONS HERE
void RGB_update(int LED, byte RED, byte GREEN, byte BLUE);//function to drive LEDs

void setup() {
  pinMode(WS2812_pin, OUTPUT);
}//setup


void loop() {


RGB_update(0,0,0,0);//LED#, RED, GREEN, BLUE
delay(1000);

}//loop



//WS2812 Driver Function
void RGB_update(int LED, byte RED, byte GREEN, byte BLUE) {
  // LED is the LED number starting with 0
  // RED, GREEN, BLUE is the brightness 0..255 setpoint for that LED
  byte ExistingPort, WS2812pinHIGH;//local variables here to speed up pinWrites
  
  if(LED>=0){//map the REG GREEN BLUE Values into the RGB[] array
  RGB[LED * 3] = GREEN;
  RGB[LED * 3 + 1] = RED;
  RGB[LED * 3 + 2] = BLUE;
  }
  
  noInterrupts();//kill the interrupts while we send the bit stream out...
  ExistingPort = PORTB; // save the status of the entire PORT B - let's us write to the entire port without messing up the other pins on that port
  WS2812pinHIGH = PORTB | 1; //this gives us a byte we can use to set the whole PORTB with the WS2812 pin HIGH
  int bitStream = numberOfLEDs * 3;//total bytes in the LED string

//This for loop runs through all of the bits (8 at a time) to set the WS2812 pin ON/OFF times
  for (int i = 0; i < bitStream; i++) {

    PORTB = WS2812pinHIGH;//bit 7  first, set the pin HIGH - it always goes high regardless of a 0/1 
    
    //here's the tricky part, check if the bit in the byte is high/low then right that status to the pin
    // (RGB[i] & B10000000) will strip away the other bits in RGB[i], so here we'll be left with B10000000 or B00000000
    // then it's easy to check if the bit is high or low by AND'ing that with the bit mask ""&& B10000000)"" this gives 1 or 0
    // if it's a 1, we'll OR that with the Existing port, thus keeping the pin HIGH, if 0 the pin is written LOW
    PORTB = ((RGB[i] & B10000000) && B10000000) | ExistingPort; 
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");//these are NOPS - these let us delay clock cycles for more precise timing 
    PORTB = ExistingPort;//okay, here we know we have to be LOW regardless of the 0/1 bit state
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");//minimum LOW time for pin regardless of 0/1 bit state

    // then do it again for the next bit and so on... see the last bit though for a slight change

    PORTB = WS2812pinHIGH;//bit 6
    PORTB = ((RGB[i] & B01000000) && B01000000) | ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
    PORTB = ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");

    PORTB = WS2812pinHIGH;//bit 5
    PORTB = ((RGB[i] & B00100000) && B00100000) | ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
    PORTB = ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");

    PORTB = WS2812pinHIGH;//bit 4
    PORTB = ((RGB[i] & B00010000) && B00010000) | ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
    PORTB = ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");

    PORTB = WS2812pinHIGH;//bit 3
    PORTB = ((RGB[i] & B00001000) && B00001000) | ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
    PORTB = ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");

    PORTB = WS2812pinHIGH;//bit 2
    PORTB = ((RGB[i] & B00000100) && B00000100) | ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
    PORTB = ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");

    PORTB = WS2812pinHIGH;//bit 1
    PORTB = ((RGB[i] & B00000010) && B00000010) | ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
    PORTB = ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");

    PORTB = WS2812pinHIGH;//bit 0
    __asm__("nop\n\t");//on this last bit, the check is much faster, so had to add a NOP here
    PORTB = ((RGB[i] & B00000001) && B00000001) | ExistingPort;
    __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t"); 
    PORTB = ExistingPort;//note there are no NOPs after writing the pin LOW, this is because the FOR Loop uses clock cycles that we can use instead of the NOPS
  }//for loop

  
  interrupts();//enable the interrupts

// all done!
}//void RGB_update