Have you looked at
https://github.com/ms-iot/samples/blob/master/GpioInterrupt/CS/GpioInterrupt/StartupTask.cs?
Modifying at bit to get some timing information and, if required, create a hardware event queue.
namespace GPIOEventqueue
{
public class HardwareEvent
{
public long ticks;
public GpioPinEdge edge;
public HardwareEvent(long ticks, GpioPinEdge edge)
{
this.ticks = ticks;
this.edge = edge;
}
}
/// <summary>
/// An empty page that can be used on its own or navigated to within a Frame.
/// </summary>
public sealed partial class MainPage : Page
{
const int GPIO_INPUT_PIN = 5;
const int SAMPLE_SIZE = 1000;
private GpioPin pin = null;
private Stopwatch stopwatch = null;
private bool capturing = false;
private List<HardwareEvent> Edges;
//private Queue<HardwareEvent> Edges;
public MainPage()
{
InitializeComponent();
NavigationCacheMode = NavigationCacheMode.Enabled;
stopwatch = Stopwatch.StartNew();
//Debug.WriteLine(" Timer frequency in ticks per second = {0}", Stopwatch.Frequency);
//Debug.WriteLine(" Timer is accurate within {0} nanoseconds", (1000L * 1000L * 1000L) / Stopwatch.Frequency);
// Timer frequency in ticks per second = 19200000
// Timer is accurate within 52 nanoseconds
SetupGpio();
Edges = new List<HardwareEvent>();
//Edges = new Queue<HardwareEvent>();
Loaded += (sender, e) =>
{
if (pin != null)
pin.ValueChanged += Pin_ValueChanged;
};
Unloaded += (sender, e) =>
{
if (pin != null)
pin.ValueChanged -= Pin_ValueChanged;
};
}
private void SetupGpio()
{
pin = null;
try
{
GpioController gpio = GpioController.GetDefault();
if (gpio != null)
{
pin = gpio.OpenPin(GPIO_INPUT_PIN);
if (pin != null)
{
pin.SetDriveMode(GpioPinDriveMode.Input);
}
}
}
catch(Exception ex)
{
Debug.WriteLine(ex.Message);
}
}
private void Pin_ValueChanged(GpioPin sender, GpioPinValueChangedEventArgs args)
{
HardwareEvent he = new HardwareEvent(stopwatch.ElapsedTicks, args.Edge);
if (capturing)
{
Edges.Add(he);
//Edges.Enqueue(he);
if (Edges.Count >= SAMPLE_SIZE)
{
capturing = false;
// just trigger the display to the screen, don't (a)wait for it to complete
Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
{
DisplayEdges();
});
}
}
}
private void CaptureButton_Click(object sender, RoutedEventArgs e)
{
Edges.Clear();
capturing = true;
}
private void DisplayEdges()
{
// TODO
}
}
I would be interested at what frequency that tops out.
riclh
