// File: LedRGB.cpp
// Control of an RGB ledstrip
// For Arduino Ethernet
// Version 2014-10-05

#include "globals.h" 

byte PwmR, PwmG, PwmB, PwmW, PwmY, PwmP, PwmC;
enum Colors {red = 0, green, blue, white, yellow, purple, cyan};  // values 0..6 

//********************************************************************************************************
// PWM modulator called by DoRGB()
void DoPWM (void) 
{
  static byte PwmCounter, PwmPause;
  
  if (PwmCounter == 0)
  {
    PORTC &= ~0x07; // all off
    if (--PwmPause == 0)
    {
      PwmPause = 200;
      PwmCounter = 255; // again
    }
  } 
  else
  {
    PwmCounter --;
    if (PwmR > PwmCounter) PORTC |= 0x01;  // red 
    if (PwmG > PwmCounter) PORTC |= 0x02;  // green 
    if (PwmB > PwmCounter) PORTC |= 0x04;  // blue 
    if (PwmW > PwmCounter) PORTC |= 0x07;  // all 3
    if (PwmY > PwmCounter) PORTC |= 0x03;  // green + red = yellow
    if (PwmP > PwmCounter) PORTC |= 0x05;  // blue + red = purple
    if (PwmC > PwmCounter) PORTC |= 0x06;  // blue + green = cyan
  }
}

//********************************************************************************************************
byte MLS8 (void) // Maximum Length Sequence pseudo random generator 
{
  static byte mls = 0xFF;  // startcondition != 0
  byte x;
  // 8 bit MLS feedback is exor of bits 0001 1101
  x = ((mls & 0x10) > 0) ^ ((mls & 0x08) > 0) ^ 
      ((mls & 0x04) > 0) ^ ((mls & 0x01) > 0);
  mls = mls >> 1; // shift 1 right
  if (x > 0) mls += 0x80; // feedback as MSB
  return mls;
}

//********************************************************************************************************
// color sequencer called at 66 kHz by ISR(TIMER2_COMPA_vect) in OneWire.cpp
void DoRGB (void) 
{
  static byte Pwm;
  static byte WaitTime;
  static Colors  UpgoingColor = red, DowngoingColor = green;
  static int RGBCounter;
  
  DoPWM();
  if(RGBCounter > 0) {RGBCounter--; return;}  else RGBCounter = 100;
  if (WaitTime > 0) {WaitTime --; return;} // wait some time at maximum
  if (Pwm < 255) Pwm++; 
  else 
  {
    Pwm = 0;
    // on peak select new color for upgoing
    DowngoingColor = UpgoingColor;
    do UpgoingColor = Colors(MLS8() & 0x07); // values 0..6
    // at same color as before or color 7 chose a new random color
      while ((UpgoingColor == DowngoingColor) | (UpgoingColor == 7));
    WaitTime = 100; // new pause
  }  
  PwmR = PwmG = PwmB = PwmW = PwmY = PwmP = PwmC = 0; // all off
  switch (UpgoingColor) 
  {
    case red:    PwmR = Pwm; break;
    case green:  PwmG = Pwm; break;
    case blue:   PwmB = Pwm; break;
    case white:  PwmW = Pwm; break;
    case yellow: PwmY = Pwm; break;
    case purple: PwmP = Pwm; break;
    case cyan:   PwmC = Pwm; break;
  }
  switch (DowngoingColor) 
  {
    case red:    PwmR = 255 - Pwm; break;
    case green:  PwmG = 255 - Pwm; break;
    case blue:   PwmB = 255 - Pwm; break;
    case white:  PwmW = 255 - Pwm; break;
    case yellow: PwmY = 255 - Pwm; break;
    case purple: PwmP = 255 - Pwm; break;
    case cyan:   PwmC = 255 - Pwm; break;
  }
}