/// <summary>
/// Read the state of the input pins. Will trigger any Onchanged events registered
/// </summary>
public void PollInputPins()
{
var result = spiConnection.Transfer(inputPollBuffer);
var state = inputPollBuffer.Rx[2];
if (state != CachedInputState)
{
CachedInputState = state;
PiFaceInputPin.SetAllPinStates(InputPins, state);
}
}
/// <summary>
/// Set up the MCP23S17 for the PiFace Digital board
/// </summary>
private void InitPiFace()
{
InputPins = new PiFaceInputPin[8];
for (int pinNo = 0; pinNo < 8; pinNo++)
{
InputPins[pinNo] = new PiFaceInputPin(pinNo);
}
OutputPins = new PiFaceOutputPin[8];
for (int pinNo = 0; pinNo < 8; pinNo++)
{
OutputPins[pinNo] = new PiFaceOutputPin(pinNo);
}
if (spiConnection == null)
{
SpiConnectionSettings spiSettings = new SpiConnectionSettings {
BitsPerWord = 8, Delay = 1, MaxSpeed = 5000000, Mode = SpiMode.Mode0
};
spiConnection = new NativeSpiConnection(driverName, spiSettings);
}
Write(mcp23s17Register.IOCON, IOCON_SEQOP);
SetAllOutputPins(0);
// initialize output and input pins
Write(mcp23s17Register.IODIRA, All_Pins_Output);
Write(mcp23s17Register.IODIRB, All_Pins_Input);
// set resistor on all input pins to pull up
Write(mcp23s17Register.GPPUB, 0xFF);
// set outputs
UpdatePiFaceOutputPins();
// Create re-usable buffer for polling input pins
CreateReusableBufferForInputPolling();
// Get the initial software input pin state and compare to actual inputs
CachedInputState = PiFaceInputPin.AllPinState(InputPins);
PollInputPins();
}
