//

// FILE: PulsePattern.cpp

// AUTHOR: Rob dot Tillaart at gmail dot com

// VERSION: see PULSEPATTERN_LIB_VERSION in .h

// PURPOSE: PulsePattern library for Arduino

//

// HISTORY:

// 0.0.1 - 2012-11-23 initial version

// 0.0.2 - 2012-11-23 adapted a static PPO

// 0.0.3 - 2012-12-27 renamed to PulsePattern

// 0.0.4 - 2012-12-27 code stable(?) enough to publish

// 0.0.5 - 2012-12-27 code cleanup+comment

// 0.0.6 - 2015-04-18 completed the state machine

// 0.0.7 - 2017-07-16 refactor & review

//

// Released to the public domain

//

// TODO

// - fast function iso array to return the next period?

// more adaptive to e.g. sensor values. (investigate)

// - test PRE 1.0 backwards compatibility

// - move code to .h file so compiler can inline?

// - optimize timer code

// - adjust timing to more accurate values -> setTimer()

// - worker should be private - how???

// - test invalid array periods

// - start en stop index ipv size?

// - pulsepattern recorder

//

#include "PulsePattern.h"

#if defined(ARDUINO) && ARDUINO >= 100

#include "Arduino.h"

#else

#include "WProgram.h"

#endif

// Predefined generator (singleton)

PulsePattern PPGenerator;

ISR(TIMER1_COMPA_vect)

{

PPGenerator.worker();

}

PulsePattern::PulsePattern()

{

_size = 0;

_state = NOTINIT;

_ar = NULL;

_cnt = 0;

_level = LOW;

_prescaler = 0;

_pin = 0;

}

void PulsePattern::init(uint8_t pin, uint16_t * ar, uint8_t size,

uint8_t level, uint8_t prescaler)

{

_pin = pin;

pinMode(_pin, OUTPUT);

stop();

_ar = ar;

_size = size;

// TODO: run over the array to test invalid values?

// constrain them 10-4095?

_level = constrain(level, LOW, HIGH);

_prescaler = constrain(prescaler, PRESCALE_1, PRESCALE_1024);

_cnt = 0;

digitalWrite(_pin, _level);

_state = STOPPED;

}

void PulsePattern::start()

{

if (_size == 0) return; // no pattern

if (_state == RUNNING) return; // no restart

setTimer(1); // start asap

_state = RUNNING;

}

void PulsePattern::stop()

{

stopTimer();

_state = STOPPED;

_level = LOW;

digitalWrite(_pin, _level);

}

void PulsePattern::worker()

{

if (_state != RUNNING) return;

// set next period & flip signal

_level = !_level;

// direct port faster

digitalWrite(_pin, _level);

// TODO: adjustment needed for code overhead when micros?;

// + 5.2 usec for digitalWrite

// + 3 usec for settimer call

OCR1A = (_ar[_cnt]) * (F_CPU/1000000L);

_cnt++;

if (_cnt >= _size) _cnt = 0; // repeat

}

// TIMER code based upon - http://www.gammon.com.au/forum/?id=11504

void PulsePattern::stopTimer()

{

TCCR1A = 0; // reset timer 1

TCCR1B = 0;

}

// TODO: can be optimized?

void PulsePattern::setTimer(const uint16_t cc) const

{

TCCR1A = 0;

TCCR1B = 0;

TCNT1 = 0; // reset counter

OCR1A = cc * 16; // compare A register value;

// * 16 makes max period 4095

// min period 12?

// 4: CTC mode, top = OCR1A

TCCR1A = _BV (COM1A1); // clear on compare

TCCR1B = _BV (WGM12) | _prescaler;

TIFR1 |= _BV (OCF1A); // clear interrupt flag

TIMSK1 = _BV (OCIE1A); // interrupt on Compare A Match

}

// END OF FILE