void WriteOctet(Octet data)
{
// The 74HCT595 shift register accepts the most significant bit first.
// SO whatever is shifted in forst ends up on output Q7/QH/Pin 7.
for (int i = 7; i >= 0; i--)
{
WriteOneBit(data[i]);
}
serialClockPositiveEdge.Low(); // Leave the clock low
}
/// <summary>
/// Writes the specified data pattern and latches it onto the output pins.
/// The operation is thread-safe.
/// </summary>
/// <param name="data">
/// The bit pattern to be written.
/// Octet[0] corresponds to output Q0 and Octet[7] corresponds to output Q7.
/// </param>
public void Write(Octet data)
{
lock (syncObject) // prevent race condition
{
latchPositiveEdge.Low();
WriteOctet(data);
latchPositiveEdge.High();
outputs = data;
outputEnableActiveLow.Low();
}
}
public SerialShiftRegister(OutputPort outputEnable,
OutputPort serialClock,
OutputPort serialData,
OutputPort latch)
{
outputEnableActiveLow = outputEnable;
serialClockPositiveEdge = serialClock;
this.serialData = serialData;
latchPositiveEdge = latch;
outputEnable.High();
latchPositiveEdge.Low();
serialClockPositiveEdge.Low();
}
/// <summary>
/// Resets the latch so that all motors and outputs are disabled. This method should be called
/// before using any of the shield's resources to ensure that the hardware is in a consistent
/// state.
/// </summary>
/// <exception cref="System.NotImplementedException"></exception>
public void InitializeShield()
{
enable.High(); // disables the latch outputs.
serialShiftRegister.Write(Octet.Zero);
enable.Low(); // Enables the parallel output register drivers.
}