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);
}
}
private void readBufs(int handle)
{
byte[] buf = new byte[4096];
int bytesread = 0;
do
{
bytesread = UniStd.read(handle, ref buf, Convert.ToUInt32(buf.Length));
if (bytesread < 0)
{
throw new IOException(string.Format("Failed to read - error {0}.", bytesread));
}
} while (bytesread > 0);
if (UniStd.lseek(handle, 0, 0) < 0)
{
throw new IOException("Failed to seek.");
}
}
