private void setEdgeDetection(byte pin, EdgeDetectionMode edge)
{
if (edge == EdgeDetectionMode.none)
{
// open file handle to gpio export
var fd = FCntl.open("/sys/class/gpio/unexport", FCntl.O_WRONLY);
if (fd < 0)
{
throw new IOException(string.Format("Failed to open gpio class - error {0}.", fd));
}
// write pin number to export gpio pin
// (don't check for errors because it raises if already unexported..)
var buf = System.Text.UTF8Encoding.UTF8.GetBytes(pin.ToString() + Environment.NewLine);
UniStd.write(fd, buf, Convert.ToUInt32(buf.Length));
FCntl.close(fd);
}
else
{
// open file handle to gpio export
var fd = FCntl.open("/sys/class/gpio/export", FCntl.O_WRONLY);
if (fd < 0)
{
throw new IOException(string.Format("Failed to open gpio class - error {0}.", fd));
}
// write pin number to export gpio pin
// (don't check for errors because it raises if already exported..)
var buf = System.Text.UTF8Encoding.UTF8.GetBytes(pin.ToString() + Environment.NewLine);
UniStd.write(fd, buf, Convert.ToUInt32(buf.Length));
FCntl.close(fd);
// wait short delay for export to complete
System.Threading.Thread.Sleep(50);
// open file handle to gpio direction
fd = FCntl.open(String.Format("/sys/class/gpio/gpio{0}/direction", pin), FCntl.O_WRONLY);
if (fd < 0)
{
throw new IOException(string.Format("Failed to open gpio direction - error {0}.", fd));
}
// write pin number to export gpio direction
buf = System.Text.UTF8Encoding.UTF8.GetBytes("in" + Environment.NewLine);
UniStd.write(fd, buf, Convert.ToUInt32(buf.Length));
FCntl.close(fd);
// open file handle to gpio edge
fd = FCntl.open(String.Format("/sys/class/gpio/gpio{0}/edge", pin), FCntl.O_WRONLY);
if (fd < 0)
{
throw new IOException(string.Format("Failed to open gpio edge - error {0}.", fd));
}
// write pin number to export gpio direction
buf = System.Text.UTF8Encoding.UTF8.GetBytes(edge.ToString() + Environment.NewLine);
UniStd.write(fd, buf, Convert.ToUInt32(buf.Length));
FCntl.close(fd);
}
}
public GpioEdgeDetector(byte pin, EdgeDetectionMode edge, int pollTimeout = 1000)
{
this.pin = pin;
this.deviceName = String.Format("/sys/class/gpio/gpio{0}/value", pin);
this.pollTimeout = pollTimeout;
// enable edge detection
setEdgeDetection(pin, edge);
// open gpio file handle
openEdgeDetectionFileHandle();
// start async polling task
cancelTokenSource = new System.Threading.CancellationTokenSource();
pollParams p = new pollParams();
p.cancelToken = cancelTokenSource.Token;
// TODO: Error Handling!
Task.Factory.StartNew(new Action <Object>(pollInterrupt), p, cancelTokenSource.Token, TaskCreationOptions.LongRunning, TaskScheduler.Default).
ContinueWith((t) => {
Console.WriteLine(String.Format("GpioEdgeDetector Error: {0}", (t.Exception != null ? t.Exception.ToString() : String.Empty)));
}, System.Threading.CancellationToken.None, TaskContinuationOptions.OnlyOnFaulted, TaskScheduler.Current);
}
/// <summary>
/// Creates a new PiFace object using the default device name and registers an interrupt service routine on PiFace inputs.
/// </summary>
/// <param name="enableInputInterruptMask">
/// Byte mask for input pins to enable interrupt.
/// </param>
/// <param name="interruptGpioPin">
/// Raspberry Pi GPIO Pin which is connected to PiFace interrupt signaling pin (default 25).
/// </param>
/// <param name="edge">
/// <see cref="EdgeDetectionMode"/> (rising/falling/both) specifies which signal edge should be detected (default falling).
/// </param>
/// <remarks>
/// Interrupt handling is only enabled if enableInputInterruptMask is > 0 and edge is not None.
/// interruptGpioPin must be preconfigured as an input on Raspberry Pi GPIO.
/// </remarks>
public PiFaceDevice(byte enableInputInterruptMask, byte interruptGpioPin = 25, EdgeDetectionMode edge = EdgeDetectionMode.falling)
: this()
{
if (enableInputInterruptMask > 0 && edge != EdgeDetectionMode.none)
{
InitializeEdgeDetection(enableInputInterruptMask);
this.EdgeDetector = new GpioEdgeDetector(interruptGpioPin, edge);
}
}
