Emulate FreqIN input using Arduino

Using Arduino Project Guidance
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I am currently using a PLUS+1 microcontroller for my project, and I am using C1P25 pin with FreqIN input. I am actually developing a simple HIL with my PC and it's going great so far, but one problem I am encountering is trying to "simulate" physical signals such as Digital and FreqIN signals.

So I've opted for using Arduino as an "intermediary" between my PC and PLUS+1 which for Digital signals, I can use Arduino's digital output signals. However, for FreqIN, Im not entirely sure how exactly to approach this. I am actually trying to simulate a speed sensor which I found this forum to be doing exactly what I need.

However, after going through it, I did not truly understand what exactly does the code do and if that's exactly what I am looking for. I am hoping I can get a bit of guidance on how to approach this, and possibly some reference.

Edit: Sorry, I should have included the code here. Thanks for pointing it out

const byte numPulsesMeasured = 16;
const unsigned long timeout = 100000UL;          // 100ms timeout, may need to adjust this

byte pulsesCounted = 0;
unsigned long firstPulseTime;
volatile unsigned int interval = 0;
float gearRatio = 1.0;

void setup()
{
  attachInterrupt(0, isr, RISING);               // every time interrupt triggered (pin 2) run function isr.
  while (interval == 0) { }                      // discard first reading
  // insert code to initialize timer 1 here
}

void isr()
{
  ++pulsesCounted;                                // tally pulses
  if (pulsesCounted == numPulsesMeasured)         // once count of 16 reached (1 revolution)
  {
    unsigned long now = micros();                 // save current clock time
    unsigned long temp = now - firstPulseTime;    // subtract last clock time from current clock time to get microS per revolution
    if (temp < timeout)
    {
      interval = (unsigned int)(temp/numPulsesMeasured);  // calculates microsec per pulse
    }
    firstPulseTime = now;                                 // set last clock time to current clock time
    pulsesCounted = 0;                                    // reset pulses counted
  }
}

void setOutputInterval(unsigned int interval)
{
  // insert code to change timer 1 TOP and OCR registers here
}

void loop()
{
  noInterrupts();
  interval = 0;
  interrupts();
  unsigned int localInterval;
  unsigned long startTime = micros();
  do
  {
    noInterrupts();
    localInterval = interval;
    interrupts();
  } while (localInterval == 0 && (micros() - startTime < timeout));
  // need code to update the gear ration somewhere....
  setOutputInterval((unsigned int)(gearRatio * (float)localInterval));
}

Cheers,
Khalid

2

Hellpers feel the same, not able to look at it....
Here's a tip: How to get the best out of this forum - Using Arduino / IDE 1.x - Arduino Forum

3

Sorry, I've edited the question to include the code

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