/*
Based on shiftRegister_softPWM_02
This program will automatically fade the LED on Q7
*/

const byte numChars = 32;
char receivedChars[numChars];

boolean newData = false;

#define NUMELEMENTS(x) (sizeof(x) / sizeof(x[0]))

// 74HC595 control
const uint8_t dataPin = 2;
const uint8_t clockPin = 3;
const uint8_t latchPin = 4;

// timing in microseconds
const uint32_t timerInterval = 2000;

// the starting intensities of the LEDs
//uint16_t pulseWidths[] = { 200 , 400, 600, 800, 1000, 1200, 2000 };
uint16_t pulseWidths[] = { 0, 0, 0, 0, 0, 0, 0 };
// index in pulseWidths for 74HC595 Q7
const uint8_t Q7 = 6;

uint8_t laPins[] = { 8, 9 };

void setup()
{
  Serial.begin(115200);
  Serial.println(F("74HC595 Software PWM 0.2"));

  pinMode(dataPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(latchPin, OUTPUT);

  for (uint8_t cnt = 0; cnt < NUMELEMENTS(laPins); cnt++)
  {
    pinMode(laPins[cnt], OUTPUT);
  }
}

void loop()
{
  recvWithStartEndMarkers();
  if (newData)
  {
    newData = false;
    parseData();
  }

  fadeQ7();

  softPWM();
}

void softPWM()
{
  static uint32_t previousMicros;
  uint32_t currentMicros = micros();
  uint8_t data = 0;

  if (currentMicros - previousMicros >= timerInterval)
  {
    previousMicros = currentMicros;

    for (unsigned int i = 0; i < NUMELEMENTS(pulseWidths); i++)
    {
      if (pulseWidths[i] > 0)
      {
        data |= 1 << i;
      }
    }
  }
  else
  {
    for (unsigned int i = 0; i < NUMELEMENTS(pulseWidths); i++)
    {
      if (currentMicros - previousMicros >= pulseWidths[i])
      {
        data &= ~(1 << i);
      }
    }
  }

  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, data << 1);
  digitalWrite(latchPin, HIGH);
}

void fadeQ7()
{
  uint32_t time = millis();
  static uint32_t lastTime;

  if(millis() - lastTime >= 50)
  {
    lastTime = millis();
    pulseWidths[Q7] += 50;
    if(pulseWidths[Q7] >= 2000)
    {
      pulseWidths[Q7] = 0;
    }
  }
}

void recvWithStartEndMarkers()
{
  static boolean recvInProgress = false;
  static byte ndx = 0;
  char startMarker = '<';
  char endMarker = '>';
  char rc;

  while (Serial.available() > 0 && newData == false)
  {
    rc = Serial.read();

    if (recvInProgress == true)
    {
      if (rc != endMarker)
      {
        receivedChars[ndx] = rc;
        ndx++;
        if (ndx >= numChars)
        {
          ndx = numChars - 1;
        }
      }
      else
      {
        receivedChars[ndx] = '\0';  // terminate the string
        recvInProgress = false;
        ndx = 0;
        newData = true;
      }
    }

    else if (rc == startMarker)
    {
      recvInProgress = true;
    }
  }
}

void parseData()
{  // split the data into its parts

  char* strtokIndx;  // this is used by strtok() as an index

  strtokIndx = strtok(receivedChars, ",");  // get the first part - the string
  uint8_t ledNum = atoi(strtokIndx);        // convert this part to an integer

  strtokIndx = strtok(NULL, ",");  // this continues where the previous call left off
  int pwmVal = atoi(strtokIndx);   // convert this part to an integer

  if(ledNum == 0)
  {
    for(uint8_t cnt = 0; cnt < NUMELEMENTS(pulseWidths); cnt++)
    {
      pulseWidths[cnt] = pwmVal;
    }
  }
  else
  {
    pulseWidths[ledNum - 1] = pwmVal;
  }
}