public void Write(GpioPort port, GpioPin pin, GpioPinValue value)
{
byte olatRegister;
byte olatRegisterValues;
if (port == GpioPort.A)
{
olatRegister = OLATA;
}
else
{
olatRegister = OLATB;
}
olatRegisterValues = _readRegister(olatRegister);
var pinAddress = _pins[pin.ToString()];
if (value == GpioPinValue.Low)
{
var pinMask = (byte)(0xFF ^ pinAddress);
olatRegisterValues &= pinMask;
}
else
{
//high
olatRegisterValues |= pinAddress;
}
_writeRegister(olatRegister, olatRegisterValues);
}
public GpioPinValue Read(GpioPort port, GpioPin pin)
{
byte gpioRegister;
byte gpioRegisterValues;
if (port == GpioPort.A)
{
gpioRegister = GPIOA;
}
else
{
gpioRegister = GPIOB;
}
gpioRegisterValues = _readRegister(gpioRegister);
var pinAddress = _pins[pin.ToString()];
if ((byte)(gpioRegisterValues & pinAddress) == 0x00)
{
return(GpioPinValue.Low);
}
else
{
return(GpioPinValue.High);
}
}
/// <summary>
/// This method preserves the OLAT / GPIO settings of all pins and
/// will only modify the pin requested and set it to the directionality specified
/// </summary>
/// <param name="port">Port A or Port B</param>
/// <param name="pin">GPIO 0-7</param>
/// <param name="mode">Input or Output</param>
public void SetGpioPinDriveMode(GpioPort port, GpioPin pin, GpioPinDriveMode mode)
{
byte olatRegister;
byte iodirRegister;
byte olatRegisterValues;
byte iodirRegisterValues;
if (port == GpioPort.A)
{
olatRegister = OLATA;
iodirRegister = IODIRA;
}
else
{
olatRegister = OLATB;
iodirRegister = IODIRB;
}
//get read values to preserve
olatRegisterValues = _readRegister(olatRegister);
iodirRegisterValues = _readRegister(iodirRegister);
var pinAddress = _pins[pin.ToString()];
switch (mode)
{
case GpioPinDriveMode.Input:
var inputPinMask = (byte)(0x00 ^ pinAddress); //exclusive OR so that we only change the one pin - others remain unchanged
iodirRegisterValues |= inputPinMask;
break;
case GpioPinDriveMode.Output:
//output logic needs to be low prior to switching to output
var outputPinMask = (byte)(0xFF ^ pinAddress);
olatRegisterValues &= outputPinMask;
_writeRegister(olatRegister, olatRegisterValues);
iodirRegisterValues &= outputPinMask;
break;
default:
Debug.WriteLine("Pin mode not current supported");
throw new Exception("Pin mode not currently supported");
break;
}
_writeRegister(iodirRegister, iodirRegisterValues);
}