Raw IR-signal receiver for Arduino with PL-IRM-2161-C438

Raw-IR-Receiver.ino

#define PIN_IR_IN    8
#define SIGNAL_TIMEOUT 8000

#define DATA_LEN 512
short buf[DATA_LEN];

void clearBuf(int range)
{
  for (int i = 0; i < range; i++)
    buf[i] = 0;
}

// see pulseIn() code. (hardware/arduino/cores/arduino/wiring_pulse.c)
unsigned long switchIn(uint8_t pin, uint8_t state, unsigned long timeout)
{
  uint8_t bit = digitalPinToBitMask(pin);
  uint8_t port = digitalPinToPort(pin);
  uint8_t stateMask = (state ? bit : 0);
  unsigned long width = 0;
  
  unsigned long numloops = 0;
  unsigned long maxloops = microsecondsToClockCycles(timeout) / 16;
  
  // wait for the signal to start
  while ((*portInputRegister(port) & bit) != stateMask)
    if (numloops++ == maxloops)
      return 0;
  
  // wait for the signal to stop
  while ((*portInputRegister(port) & bit) == stateMask) {
    if (numloops++ == maxloops)
      return 0;
    width++;
  }

  return clockCyclesToMicroseconds(width * 21 + 16); 
}

int receiveIR()
{
  // IR High Signal -> Pin is LOW  (0)
  // IR Low Signal  -> Pin is HIGH (1)
  
  // wait signal
  while (digitalRead(PIN_IR_IN) != 0);

  int i = 0;
  for (i = 0; i < DATA_LEN; i++) {
    unsigned long t = switchIn(PIN_IR_IN, (i & 0x1) ? HIGH : LOW, SIGNAL_TIMEOUT);
    if (!t) break;
    buf[i] = t;
  }

  Serial.print("Count=");  
  Serial.println(i);  
  for (int j = 0; j < i; j++) {
    Serial.println(buf[j]);
  }
  Serial.write('\n');

  clearBuf(i);
}

void setup()
{
  Serial.begin(9600);
  pinMode(PIN_IR_IN, INPUT);
  
  clearBuf(DATA_LEN);
  Serial.println("setup");
}

void loop()
{
  Serial.println("ready");
  receiveIR();
}