WTV020SD16P.cpp

/*
 WTV020SD16P.cpp Version 1.2
 
 Library to control a WTV020-SD-16P module to play voices from an Arduino board.
 Created by Diego J. Arevalo, August 6th, 2012.
 Modifed by Ryszard Malinowski November 30, 2014.
 Modifed by Dan F  March 2015
  
 Released into the public domain.
 
 Changes:
 V1.0 - Original library written by Diego J. Arevalo
 V1.1 - Changes by Ryszard Malinowski:
        1. Add "delayMicros" function execute exact delay from the last call
        2. Fix clock timing in "setCommand" function
        3. Add "setVolume" function
        4. Fix "unmute" function to restore original volume
Padawan - Removed reset

 v1.2 - Renamed .cpp & .h to WTV020SD16P

 */

#include "Arduino.h"
#include "WTV020SD16P.h"

const unsigned int PLAY_PAUSE = 0xFFFE;
const unsigned int STOP = 0xFFFF;
const unsigned int VOLUME_MIN = 0xFFF0;
const unsigned int VOLUME_MAX = 0xFFF7;

WTV020SD16P::WTV020SD16P(int clockPin,int dataPin,int busyPin)
{
  // Save private values from constructor
  _clockPin=clockPin;
  _dataPin=dataPin;
  _busyPin=busyPin;
  
  // Set initial values
  _busyPinState=HIGH;
  _currentVolume = VOLUME_MAX;

  // Initialize timer
  _lastMicros = 0;
  delayMicros(0);

  // Set pins
  
  pinMode(_clockPin, OUTPUT);
  pinMode(_dataPin, OUTPUT);
  pinMode(_busyPin, INPUT);

}



// Public: Play entire song and wait till song finishes
void WTV020SD16P::playVoice(unsigned int voiceNumber){
  sendCommand(voiceNumber);
  // Wait 20ms for busy to be active
  delayMicros(20000);
  // Wait till song ends
  _busyPinState=digitalRead(_busyPin);
  while(_busyPinState==HIGH){
    _busyPinState=digitalRead(_busyPin);
  }
}

// Public: Start playing song and return
void WTV020SD16P::asyncPlayVoice(unsigned int voiceNumber){
  sendCommand(voiceNumber);
}

// Public: Stop playing song
void WTV020SD16P::stopVoice(){
  sendCommand(STOP);
}

// Public: Pause/Resume song
void WTV020SD16P::pauseVoice(){
  sendCommand(PLAY_PAUSE);
}

// Public: Mute sound - same as setVolume(0)
void WTV020SD16P::mute(){
  sendCommand(VOLUME_MIN);
}

// Public: Unmute sound restoring the previous volume
void WTV020SD16P::unmute(){
  sendCommand(_currentVolume);
}

// Public: Set volume
void WTV020SD16P::setVolume(unsigned int volume){
  if(volume < 0x0008) {
    _currentVolume = VOLUME_MIN + volume;
    sendCommand(_currentVolume);
  }
}


// Private: Send command to sound module
void WTV020SD16P::sendCommand(unsigned int command) {
  
  //Start bit Low level pulse.
  digitalWrite(_clockPin, LOW);
  // Initialize timer
  delayMicros(0);
  // Wait Start bit length minus 50 us
  delayMicros(1950);
  for (unsigned int mask = 0x8000; mask > 0; mask >>= 1) {
    //Clock low level pulse.
    digitalWrite(_clockPin, LOW);
    delayMicros(50);
    //Write data setup.
    if (command & mask) {
      digitalWrite(_dataPin, HIGH);
    } else {
      digitalWrite(_dataPin, LOW);
    }
    //Write data hold.
    delayMicros(50);
    //Clock high level pulse.
    digitalWrite(_clockPin, HIGH);
    delayMicros(100);
  }
  //Stop bit high level pulse (additional 1900us).
  delayMicros(1900);
}


// Private: Wait specified time since the last wait
void WTV020SD16P::delayMicros(unsigned long delayMicros) {
  unsigned long stopMicros;
  unsigned long currentMicros;
  // set current time
  if (delayMicros == 0) {
    _lastMicros = micros();
	return;
  }
  // Start waiting loop
  stopMicros = _lastMicros + delayMicros;
  currentMicros = micros();
  // If time already passed then return withoit delay
  if ((stopMicros  == currentMicros) || (_lastMicros < stopMicros  && stopMicros < currentMicros) || (stopMicros < currentMicros && currentMicros < _lastMicros)) {
	  _lastMicros = currentMicros;
  } else {
    // Wait remaining time left 
    delayMicroseconds(stopMicros - currentMicros);
    _lastMicros = stopMicros;
  }
  
}