DigistumpArduino/hardware/digistump/avr/libraries/SoftRcPulseIn/SoftRcPulseIn.cpp

/*
 English: by RC Navy (2012)
 =======
 <SoftRcPulseIn>: an asynchronous library to read Input Pulse Width from standard Hobby Radio-Control. This library is a non-blocking version of pulseIn().
 http://p.loussouarn.free.fr

 Francais: par RC Navy (2012)
 ========
 <SoftRcPulseIn>: une librairie asynchrone pour lire les largeur d'impulsions des Radio-Commandes standards. Cette librairie est une version non bloquante de pulsIn().
 http://p.loussouarn.free.fr
*/

#include "SoftRcPulseIn.h"

#define LIB_VERSION					1
#define LIB_REVISION				0

#define STR(s)						#s
#define MAKE_TEXT_VER_REV(Ver,Rev)	STR(Ver)"."STR(Rev)

#define LIB_TEXT_VERSION_REVISION	MAKE_TEXT_VER_REV(LIB_VERSION,LIB_REVISION) /* Make Full version as a string "Ver.Rev" */

SoftRcPulseIn *SoftRcPulseIn::first;

SoftRcPulseIn::SoftRcPulseIn(void)
{
}

uint8_t SoftRcPulseIn::attach(uint8_t Pin, uint16_t PulseMin_us/*=600*/, uint16_t PulseMax_us/*=2400*/)
{
uint8_t Ret=0;

	_Pin=Pin;
	_PinMask=TinyPinChange_PinToMsk(Pin);
	_Min_us=PulseMin_us;
	_Max_us=PulseMax_us;
	next = first;
	first = this;
	pinMode(_Pin,INPUT);
	_VirtualPortIdx=TinyPinChange_RegisterIsr(_Pin,SoftRcPulseIn::SoftRcPulseInInterrupt);
	if(_VirtualPortIdx>=0)
	{
	  TinyPinChange_EnablePin(_Pin);
	  Ret=1;
	}
	return(Ret);
}

int SoftRcPulseIn::LibVersion(void)
{
  return(LIB_VERSION);
}

int SoftRcPulseIn::LibRevision(void)
{
  return(LIB_REVISION);
}

char *SoftRcPulseIn::LibTextVersionRevision(void)
{
  return(LIB_TEXT_VERSION_REVISION);
}

uint8_t SoftRcPulseIn::available(void)
{
boolean Ret=0;
uint16_t PulseWidth_us;

  if(_Available)
  {
	noInterrupts();
	PulseWidth_us=_Width_us;
	interrupts();
	Ret=_Available && (PulseWidth_us>=_Min_us) && (PulseWidth_us<=_Max_us);
	_Available=0;
  }
  return(Ret);
}

uint16_t SoftRcPulseIn::width_us(void)
{
uint16_t PulseWidth_us;
  noInterrupts();
  PulseWidth_us=_Width_us;
  interrupts();
  return(PulseWidth_us);  
}

void SoftRcPulseIn::SoftRcPulseInInterrupt(void)
{
SoftRcPulseIn *RcPulseIn;

  for ( RcPulseIn = first; RcPulseIn != 0; RcPulseIn = RcPulseIn->next )
  {
    if(TinyPinChange_GetPinEvent(RcPulseIn->_VirtualPortIdx)&RcPulseIn->_PinMask)
    {
	  if(digitalRead(RcPulseIn->_Pin))
	  {
		  /* High level, rising edge: start chrono */
		  RcPulseIn->_Start_us=micros();
	  }
	  else
	  {
		  /* Low level, falling edge: stop chrono */
		  RcPulseIn->_Width_us=micros()-RcPulseIn->_Start_us;
		  RcPulseIn->_Available=1;
	  }
    }
  }
}