/// <summary>
/// Transfers data to and from the SPI device in duplex mode.
/// </summary>
/// <param name="Buffer">The buffer containing the data to write. After the transfer, this will contain
/// the data that was read from the device.</param>
public void TransferData(byte[] Buffer)
{
lock (TransferLock)
{
GCHandle bufferHandle = GCHandle.Alloc(Buffer, GCHandleType.Pinned);
PiSpi_Result result = PiSpi_TransferData(Handle, bufferHandle.AddrOfPinnedObject(), (uint)Buffer.Length);
bufferHandle.Free();
if (result != PiSpi_Result.PiSpi_OK)
{
string error = Marshal.PtrToStringAnsi(PiSpi_GetLastError());
throw new Exception($"Error during a SPI transfer: {error}");
}
}
}
/// <summary>
/// Creates a new SPI device. This will use the standard SPI device 0 pins for SCLK, MISO, and MOSI.
/// It will also initialize the chip select pin to output mode and set it HIGH.
/// </summary>
/// <param name="ChipSelectPin">The number of the chip select pin for this device. This uses the
/// BCM pin layout. To find what the pin number is for a given physical pin, run `gpio readall`
/// on your Pi.</param>
/// <param name="BitRate">The speed of the SPI communications for this device, in Hz.</param>
/// <param name="Mode">The SPI mode that this device uses</param>
/// <param name="TimeBeforeRead">The delay (in microseconds) between pulling the chip select pin low
/// and starting to read/write data from/to the device.</param>
/// <param name="TimeBetweenBytes">The delay (in microseconds) to wait between reading and writing
/// individual bytes. Some devices have specific timings for this; consult your device's datasheet.
/// </param>
/// <param name="TimeAfterRead">The delay (in microseconds) to wait after finishing a data read/write
/// before setting the chip select pin back to high (unselecting the device).</param>
/// <param name="TimeBetweenReads">The delay (in microseconds) to wait after unselecting a device before
/// it can be selected again for a subsequent read/write.</param>
public SpiDevice(
byte ChipSelectPin,
uint BitRate,
SpiMode Mode,
byte TimeBeforeRead,
byte TimeBetweenBytes,
byte TimeAfterRead,
byte TimeBetweenReads)
{
PiSpi_Result result = PiSpi_CreateDevice(ChipSelectPin, BitRate, Mode,
TimeBeforeRead, TimeBetweenBytes, TimeAfterRead, TimeBetweenReads, out IntPtr handle);
if (result != PiSpi_Result.PiSpi_OK)
{
string error = Marshal.PtrToStringAnsi(PiSpi_GetLastError());
throw new Exception($"Error creating SPI device: {error}");
}
Handle = handle;
}
