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irSend.cpp
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#include "IRremote.h"
#include "IRremoteInt.h"
static uint32_t _irFrequency = 38000;
static uint32_t _1bitus = 1000000/_irFrequency;
//+=============================================================================
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
}
//+=============================================================================
// 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)
{
uint32_t highus = _1bitus/2 * 77;
uint32_t lowus = _1bitus/2 * 77;
int cnt = time / _1bitus;
for( int i = 0; i < cnt; i++){
digitalWrite(TIMER_PWM_PIN, HIGH);
custom_delay_usec(highus);
digitalWrite(TIMER_PWM_PIN, LOW);
custom_delay_usec(lowus);
}
}
//+=============================================================================
// 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)
{
uint32_t highus = _1bitus/2 * 77;
uint32_t lowus = _1bitus/2 * 77;
int cnt = time / _1bitus;
for( int i = 0; i < cnt; i++){
digitalWrite(TIMER_PWM_PIN, LOW);
custom_delay_usec(highus);
digitalWrite(TIMER_PWM_PIN, LOW);
custom_delay_usec(lowus);
}
}
//+=============================================================================
// 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)
{
_irFrequency = khz * 1000;
_1bitus = 1000000/_irFrequency;
// Disable the Timer2 Interrupt (which is used for receiving IR)
//TIMER_DISABLE_INTR; //Timer2 Overflow Interrupt
pinMode(TIMER_PWM_PIN, OUTPUT);
digitalWrite(TIMER_PWM_PIN, LOW); // When not sending PWM, 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 = ESP.getCycleCount();
unsigned long endMicros = start + uSecs - 4;
if (endMicros < start) { // Check if overflow
while ( ESP.getCycleCount() > start ) {} // wait until overflow
}
while ( ESP.getCycleCount() < endMicros ) {} // normal wait
}
//else {
// __asm__("nop\n\t"); // must have or compiler optimizes out
//}
}