// RefOsc = new Reference(); // (23, 22);
//FrequencyGate.Reference();
// RefOsc.PWMFrequency = 10000;
//RefOsc.RefFrequencyStart();
/// <summary>
/// Trigger a sensor reading
/// Convert ticks to distance using TicksToDistance below
/// </summary>
/// <returns>Number of ticks it takes to get back sonic pulse</returns>
long Ping()
{
// Reset Sensor
endTick = 0L;
GpioChangeCount btick = gpcc.Reset();
Console.WriteLine("BeginTick After reset = " + beginTick.ToString());
btick = gpcc.Read();
Console.WriteLine("BeginTick = " + beginTick.ToString());
beginTick = btick.Count;
portOut.Write(GpioPinValue.High);
// Thread.Sleep(1);
// Trigger Sonic Pulse
portOut.Write(GpioPinValue.Low);
// Start Clock
// Wait 1/20 second (this could be set as a variable instead of constant)
Thread.Sleep(50);
endTick = etick.Count;
Console.WriteLine("EndTick = " + endTick.ToString());
if (endTick > 0L)
{
// Calculate Difference
long elapsed = (long)(endTick - beginTick);
// Subtract out fixed overhead (interrupt lag, etc.)
elapsed -= LatencyTicks;
Console.WriteLine("Elapsed = " + elapsed.ToString());
if (elapsed < 0L)
{
elapsed = 0L;
}
// Return elapsed ticks
return(elapsed);
}
// Sonic pulse wasn't detected within 1/20 second
return(-1L);
}
/// <summary>
/// This interrupt will trigger when detector receives back reflected sonic pulse
/// </summary>
/// <param name="data1">Not used</param>
/// <param name="data2">Not used</param>
/// <param name="time">Transfer to endTick to calculated sound pulse travel time</param>
void InterIn_OnInterrupt(object sender, GpioPinValueChangedEventArgs e)
{
// if (gpcc.IsStarted) { gpcc.Stop(); }
// save the ticks when pulse was received back
//if (e.Edge == GpioPinEdge.RisingEdge)
//{
// beginTick = (long)gpcc.Read().Count;
// // Console.WriteLine("begintick = " + beginTick.ToString());
//};
if (e.Edge == GpioPinEdge.FallingEdge)
{
etick = gpcc.Read();
//endTick = (long)gpcc.Read().Count;
//Console.WriteLine("EndTick = " + endTick.ToString());
}
;
//GpioChangeCount etick = gpcc.Reset();
// endTick = etick.Count;
}
public static void Main()
{
Console.WriteLine("Change Counter test running");
// Initialise PWM output pin
PwmController pwmc = PwmController.GetDefault();
pwmc.SetDesiredFrequency(PWM_FREQUENCY);
PwmPin pwmTestPin = pwmc.OpenPin(PWM_OUTPUT_PIN);
pwmTestPin.SetActiveDutyCyclePercentage(0.5);
Console.WriteLine($"Open PWM pin {PWM_OUTPUT_PIN} frequency {pwmc.ActualFrequency}");
Console.WriteLine($"This pin must be connected to GpioChangeCounter pin {COUNTER_INPUT_PIN}");
// Initialise count pin by opening GPIO as input
GpioPin countPin = GpioController.GetDefault().OpenPin(COUNTER_INPUT_PIN);
countPin.SetDriveMode(GpioPinDriveMode.InputPullUp);
// Create a Counter passing in the GPIO pin
GpioChangeCounter gpcc = new GpioChangeCounter(countPin);
// Counter both raising and falling edges
gpcc.Polarity = GpioChangePolarity.Both;
Console.WriteLine($"Counter pin {COUNTER_INPUT_PIN} created");
// Start counter
gpcc.Start();
// Read count before we start PWM ( should be 0 )
// We want to save the start relative time
GpioChangeCount count1 = gpcc.Read();
// Start PWM signal
pwmTestPin.Start();
// Wait 1 Sec
Thread.Sleep(1000);
// Read current count
GpioChangeCount count2 = gpcc.Read();
// Stop PWM signal & counter
pwmTestPin.Stop();
gpcc.Stop();
// Change polarity of counter so only counting rising edges
gpcc.Polarity = GpioChangePolarity.Rising;
gpcc.Start();
GpioChangeCount count3 = gpcc.Reset();
pwmTestPin.Start();
// Wait 1 Sec
Thread.Sleep(1000);
pwmTestPin.Stop();
// Read count
GpioChangeCount count4 = gpcc.Read();
gpcc.Stop();
DisplayResults("Count pulses for 1 second with both edges", count1, count2);
DisplayResults("Count pulses for 1 second with just rising edge", count3, count4);
// Next test tries to measure the frequncy of the PWM signal
pwmTestPin.Start();
gpcc.Start();
while (true)
{
// Reset Counter to zero
GpioChangeCount countStart = gpcc.Reset();
Thread.Sleep(1000);
// Wait 1 sec and read again
GpioChangeCount countEnd = gpcc.Read();
// Sleep is not accurate so calculate actual time in secounds based of relative time differences of the 2 counts
// Ticks are in 100 nano sec increments
double periodSecs = (double)(countEnd.RelativeTime.Ticks - countStart.RelativeTime.Ticks) / 10000000000.0;
int frequecy = (int)((double)countEnd.Count / periodSecs);
Console.WriteLine($"Period {periodSecs:F6} Sec | Frequency {frequecy} Hz");
}
}
static void DisplayResults(string text, GpioChangeCount start, GpioChangeCount end)
{
TimeSpan period = end.RelativeTime - start.RelativeTime;
Console.WriteLine($"Count {text} Time:{period} Count:{end.Count}");
}
