/// <summary>
/// Constructor for a single MCP23S17 device.
/// </summary>
/// <param name="dev">SPI slave device object.</param>
public Device(IO.Interfaces.SPI.Device dev)
{
this.dev = dev;
// Configure the MCP23S17
WriteRegister8(IOCON, 0x00);
WriteRegister16(IODIR, 0xFFFF);
WriteRegister16(IPOL, 0x0000);
WriteRegister16(GPINTEN, 0x0000);
WriteRegister16(DEFVAL, 0x0000);
WriteRegister16(INTCON, 0x0000);
}
/// <summary>
/// Constructor for a chain of one or more SN74HC595 shift registers.
/// </summary>
/// <param name="dev">SPI device object.</param>
/// <param name="stages">Number of stages in the chain.</param>
/// <param name="initialstate">Initial shift register chain state.</param>
public Device(IO.Interfaces.SPI.Device dev, int stages = 1, byte[] initialstate = null)
{
// Validate parameters
if (stages < 1)
{
throw new System.Exception("stages paramter is invalid");
}
if (initialstate != null)
{
if (initialstate.Length != stages)
{
throw new System.Exception("initialstate parameter length is invalid");
}
}
// Save the SPI device object
spidev = dev;
// Allocate shift register state buffer
statebuf = new byte[stages];
// Initialize shift register state buffer
if (initialstate == null)
{
for (int i = 0; i < state.Length; i++)
{
statebuf[i] = 0;
}
}
else
{
statebuf = initialstate;
}
// Shift out initial register state
spidev.Write(statebuf, statebuf.Length);
}
