/// <summary>
/// Gets the mapped address for a register.
/// </summary>
/// <param name="register">The register.</param>
/// <param name="port">The bank of I/O ports used with the register.</param>
/// <param name="bankStyle">The bank style that determines how the register addresses are grouped.</param>
/// <returns>The byte address of the register for the given port bank and bank style.</returns>
private byte GetMappedAddress(Register register, Port port = Port.PortA,
BankStyle bankStyle = BankStyle.Sequential)
{
if (port != Port.PortA && port != Port.PortB)
{
throw new ArgumentOutOfRangeException(nameof(port));
}
if (bankStyle != BankStyle.Separated && bankStyle != BankStyle.Sequential)
{
throw new ArgumentOutOfRangeException(nameof(bankStyle));
}
byte address = (byte)register;
// There is no mapping for 8 bit expanders
if (PinCount == 8)
{
return(address);
}
if (bankStyle == BankStyle.Sequential)
{
// Registers for each bank are sequential
// (IODIRA = 0x00, IODIRB = 0x01, IPOLA = 0x02, IPOLB = 0x03, ...)
address += address;
return(port == Port.PortA ? address : ++address);
}
// Registers for each bank are separated
// (IODIRA = 0x00, ... OLATA = 0x0A, IODIRB = 0x10, ... OLATB = 0x1A)
return(port == Port.PortA ? address : address += 0x10);
}
public void Get_Mapped_Address(Register register, Port port, BankStyle bankStyle, byte expectedMappedAddress)
{
TestMappedBus bus = new TestMappedBus();
McpMock mock = new McpMock(bus, bankStyle);
mock.Write(register, port);
Assert.Equal(expectedMappedAddress, bus.LastAddress);
}
public void Get_Mapped_Address(Register register, Port port, BankStyle bankStyle, byte expectedMappedAddress)
{
SpiDeviceMock spiDeviceMock = new SpiDeviceMock(ports: 2);
BankStyleMock mock = new BankStyleMock(spiDeviceMock, bankStyle);
mock.Read(register, port);
// Reads are full duplex- commands go to "Write"
Assert.Equal(expectedMappedAddress, spiDeviceMock.DeviceMock.LastWriteBuffer[0]);
}
/// <summary>
/// A general purpose parallel I/O expansion for I2C or SPI applications.
/// </summary>
/// <param name="bus">The bus the device is connected to.</param>
/// <param name="reset">The output pin number that is connected to the hardware reset.</param>
/// <param name="interruptA">The input pin number that is connected to the interrupt for Port A (INTA).</param>
/// <param name="interruptB">The input pin number that is connected to the interrupt for Port B (INTB).</param>
/// <param name="masterController">
/// The controller for the reset and interrupt pins. If not specified, the default controller will be used.
/// </param>
/// <param name="bankStyle">
/// The current bank style of the ports. This does not set the bank style- it tells us what the bank style is.
/// It is *highly* recommended not to change the bank style from the default as there is no direct way to
/// detect what style the chip is in and most apps will fail if the chip is not set to defaults. This setting
/// has no impact on 8-bit expanders.
/// </param>
/// <param name="shouldDispose">True to dispose the Gpio Controller</param>
protected Mcp23xxx(BusAdapter bus, int reset = -1, int interruptA = -1, int interruptB = -1,
GpioController masterController = null, BankStyle bankStyle = BankStyle.Sequential, bool shouldDispose = true)
{
_bus = bus;
_bankStyle = bankStyle;
_shouldDispose = masterController == null ? true : shouldDispose;
_reset = reset;
_interruptA = interruptA;
_interruptB = interruptB;
// Only need master controller if there are external pins provided.
if (_reset != -1 || _interruptA != -1 || _interruptB != -1)
{
_masterGpioController = masterController ?? new GpioController();
if (_interruptA != -1)
{
_masterGpioController.OpenPin(_interruptA, PinMode.Input);
}
if (_interruptB != -1)
{
_masterGpioController.OpenPin(_interruptB, PinMode.Input);
}
if (_reset != -1)
{
_masterGpioController.OpenPin(_reset, PinMode.Output);
Disable();
}
}
if (!_disabled)
{
// Set all of the pins to input, GPIO outputs to low, and set input polarity to match the input.
// This is the normal power-on / reset state of the Mcp23xxx chips.
if (PinCount == 8)
{
InternalWriteByte(Register.IODIR, 0xFF, Port.PortA);
InternalWriteByte(Register.GPIO, 0x00, Port.PortA);
InternalWriteByte(Register.IPOL, 0x00, Port.PortA);
}
else
{
InternalWriteUInt16(Register.IODIR, 0xFFFF);
InternalWriteUInt16(Register.GPIO, 0x0000);
InternalWriteUInt16(Register.IPOL, 0x0000);
}
}
}
/// <summary>
/// Disables the device by setting the reset pin low.
/// </summary>
public void Disable()
{
if (_reset == -1)
{
throw new InvalidOperationException("No reset pin configured.");
}
_masterGpioController.Write(_reset, PinValue.Low);
// Registers will all be reset when re-enabled
_bankStyle = BankStyle.Sequential;
_increments = true;
_disabled = true;
}
public BankStyleMock(SpiDevice device, BankStyle bankStyle)
: base(new SpiAdapter(device, 0x20), bankStyle: bankStyle)
{
}
public McpMock(IBusDevice device, BankStyle bankStyle)
: base(device, 0x20, bankStyle: bankStyle)
{
}