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irSend.cpp
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#include "IRremote.h"
#include "IRremoteInt.h"
#ifdef SENDING_SUPPORTED
//+=============================================================================
void IRsend::sendRaw (const unsigned int buf[], unsigned int len, unsigned int hz)
{
// Set IR carrier frequency
enableIROut(hz);
for (unsigned int i = 0; i < len; i++) {
if (i & 1) space(buf[i]) ;
else mark (buf[i]) ;
}
space(0); // Always end with the LED off
}
#ifdef USE_SOFT_CARRIER
void inline IRsend::sleepMicros(unsigned long us)
{
#ifdef USE_SPIN_WAIT
sleepUntilMicros(micros() + us);
#else
if (us > 0U) // Is this necessary? (Official docu https://www.arduino.cc/en/Reference/DelayMicroseconds does not tell.)
delayMicroseconds((unsigned int) us);
#endif
}
void inline IRsend::sleepUntilMicros(unsigned long targetTime)
{
#ifdef USE_SPIN_WAIT
while (micros() < targetTime)
;
#else
unsigned long now = micros();
if (now < targetTime)
sleepMicros(targetTime - now);
#endif
}
#endif // USE_SOFT_CARRIER
//+=============================================================================
// Sends an IR mark for the specified number of microseconds.
// The mark output is modulated at the PWM frequency.
//
void IRsend::mark(unsigned int time)
{
#ifdef USE_SOFT_CARRIER
unsigned long start = micros();
unsigned long stop = start + time;
if (stop + periodTime < start)
// Counter wrap-around, happens very seldomly, but CAN happen.
// Just give up instead of possibly damaging the hardware.
return;
unsigned long nextPeriodEnding = start;
unsigned long now = micros();
while (now < stop) {
SENDPIN_ON(sendPin);
sleepMicros(periodOnTime);
SENDPIN_OFF(sendPin);
nextPeriodEnding += periodTime;
sleepUntilMicros(nextPeriodEnding);
now = micros();
}
#else
TIMER_ENABLE_PWM; // Enable pin 3 PWM output
if (time > 0) custom_delay_usec(time);
#endif
}
//+=============================================================================
// Leave pin off for time (given in microseconds)
// Sends an IR space for the specified number of microseconds.
// A space is no output, so the PWM output is disabled.
//
void IRsend::space (unsigned int time)
{
TIMER_DISABLE_PWM; // Disable pin 3 PWM output
if (time > 0) IRsend::custom_delay_usec(time);
}
//+=============================================================================
// Enables IR output. The khz value controls the modulation frequency in kilohertz.
// The IR output will be on pin 3 (OC2B).
// This routine is designed for 36-40KHz; if you use it for other values, it's up to you
// to make sure it gives reasonable results. (Watch out for overflow / underflow / rounding.)
// TIMER2 is used in phase-correct PWM mode, with OCR2A controlling the frequency and OCR2B
// controlling the duty cycle.
// There is no prescaling, so the output frequency is 16MHz / (2 * OCR2A)
// To turn the output on and off, we leave the PWM running, but connect and disconnect the output pin.
// A few hours staring at the ATmega documentation and this will all make sense.
// See my Secrets of Arduino PWM at http://arcfn.com/2009/07/secrets-of-arduino-pwm.html for details.
//
void IRsend::enableIROut (int khz)
{
#ifdef USE_SOFT_CARRIER
periodTime = (1000U + khz/2) / khz; // = 1000/khz + 1/2 = round(1000.0/khz)
periodOnTime = periodTime * DUTY_CYCLE / 100U - PULSE_CORRECTION;
#endif
// Disable the Timer2 Interrupt (which is used for receiving IR)
TIMER_DISABLE_INTR; //Timer2 Overflow Interrupt
pinMode(sendPin, OUTPUT);
SENDPIN_OFF(sendPin); // When not sending, we want it low
// COM2A = 00: disconnect OC2A
// COM2B = 00: disconnect OC2B; to send signal set to 10: OC2B non-inverted
// WGM2 = 101: phase-correct PWM with OCRA as top
// CS2 = 000: no prescaling
// The top value for the timer. The modulation frequency will be SYSCLOCK / 2 / OCR2A.
TIMER_CONFIG_KHZ(khz);
}
//+=============================================================================
// Custom delay function that circumvents Arduino's delayMicroseconds limit
void IRsend::custom_delay_usec(unsigned long uSecs) {
if (uSecs > 4) {
unsigned long start = micros();
unsigned long endMicros = start + uSecs - 4;
if (endMicros < start) { // Check if overflow
while ( micros() > start ) {} // wait until overflow
}
while ( micros() < endMicros ) {} // normal wait
}
//else {
// __asm__("nop\n\t"); // must have or compiler optimizes out
//}
}
#endif // SENDING_SUPPORTED