Class Mcp23xxx

Provide an interface to connect to a MCP23xxx port expander

Assembly: Mcp23xxx.dll

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Declaration

public abstract class Mcp23xxx : IDigitalInputOutputController, IDigitalInputController, IDigitalOutputController, ISpiPeripheral, II2cPeripheral, IDigitalInterruptController, IPinController

Derived:
Meadow.Foundation.ICs.IOExpanders.Mcp23x0x

Implements:
Meadow.Hardware.IDigitalInputOutputController, Meadow.Hardware.IDigitalInputController, Meadow.Hardware.IDigitalOutputController, Meadow.Hardware.ISpiPeripheral, Meadow.Hardware.II2cPeripheral, Meadow.Hardware.IDigitalInterruptController, Meadow.Hardware.IPinController

Properties

NumberOfPins

The number of IO pins available on the device

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Declaration

public abstract int NumberOfPins { get; }

DefaultSpiBusSpeed

The default SPI bus speed for the device

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Declaration

public Frequency DefaultSpiBusSpeed { get; }

SpiBusSpeed

The SPI bus speed for the device

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Declaration

public Frequency SpiBusSpeed { get; set; }

DefaultSpiBusMode

The default SPI bus mode for the device

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Declaration

public SpiClockConfiguration.Mode DefaultSpiBusMode { get; }

SpiBusMode

The SPI bus mode for the device

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Declaration

public SpiClockConfiguration.Mode SpiBusMode { get; set; }

DefaultI2cAddress

The default I2C address for the peripheral

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Declaration

public byte DefaultI2cAddress { get; }

Fields

_lock

object for using lock() to do thread sync

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Declaration

protected object _lock

Methods

GetAddressFromPins(bool, bool, bool)

Help method to get address from address pin configuration

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Declaration

public static byte GetAddressFromPins(bool pinA0, bool pinA1, bool pinA2)

Returns

System.Byte: The device address

Parameters

Type	Name	Description
System.Boolean	pinA0	State of A0 address pin - true if high
System.Boolean	pinA1	State of A1 address pin - true if high
System.Boolean	pinA2	State of A2 address pin - true if high

ResetMcp()

Reset the MCPxxxx expander Requires using a reset port

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Declaration

public void ResetMcp()

IsValidPin(IPin)

Checks if a pin exists on the Mcp23xxx

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Declaration

protected abstract bool IsValidPin(IPin pin)

Returns

System.Boolean

Parameters

Type	Name
Meadow.Hardware.IPin	pin

CreateDigitalOutputPort(IPin, bool, OutputType)

Creates a new DigitalOutputPort using the specified pin and initial state

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Declaration

public virtual IDigitalOutputPort CreateDigitalOutputPort(IPin pin, bool initialState = false, OutputType outputType = OutputType.OpenDrain)

Returns

Meadow.Hardware.IDigitalOutputPort: IDigitalOutputPort

Parameters

Type	Name	Description
Meadow.Hardware.IPin	pin	The pin representing the port
System.Boolean	initialState	Whether the pin is initially high or low
Meadow.Hardware.OutputType	outputType	The output type

CreateDigitalInputPort(IPin, ResistorMode)

Creates a new DigitalInputPort using the specified pin

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Declaration

public IDigitalInputPort CreateDigitalInputPort(IPin pin, ResistorMode resistorMode = ResistorMode.Disabled)

Returns

Meadow.Hardware.IDigitalInputPort: IDigitalInputPort

Parameters

Type	Name	Description
Meadow.Hardware.IPin	pin	The pin representing the port
Meadow.Hardware.ResistorMode	resistorMode	The port resistor mode

CreateDigitalInterruptPort(IPin, InterruptMode, ResistorMode)

Creates a new DigitalInputPort using the specified pin

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Declaration

public IDigitalInterruptPort CreateDigitalInterruptPort(IPin pin, InterruptMode interruptMode = InterruptMode.None, ResistorMode resistorMode = ResistorMode.Disabled)

Returns

Meadow.Hardware.IDigitalInterruptPort: IDigitalInterruptPort

Parameters

Type	Name	Description
Meadow.Hardware.IPin	pin	The pin representing the port
Meadow.Hardware.InterruptMode	interruptMode	The port interrupt mode
Meadow.Hardware.ResistorMode	resistorMode	The port resistor mode

CreateDigitalInterruptPort(IPin, InterruptMode, ResistorMode, TimeSpan)

Creates a new DigitalInputPort using the specified pin

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Declaration

public IDigitalInterruptPort CreateDigitalInterruptPort(IPin pin, InterruptMode interruptMode, ResistorMode resistorMode, TimeSpan debounceDuration)

Returns

Meadow.Hardware.IDigitalInterruptPort: IDigitalInterruptPort

Parameters

Type	Name	Description
Meadow.Hardware.IPin	pin	The pin representing the port
Meadow.Hardware.InterruptMode	interruptMode	The port interrupt mode
Meadow.Hardware.ResistorMode	resistorMode	The port resistor mode
System.TimeSpan	debounceDuration	The debounce duration

CreateDigitalInterruptPort(IPin, InterruptMode, ResistorMode, TimeSpan, TimeSpan)

Creates a new DigitalInputPort using the specified pin

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Declaration

public IDigitalInterruptPort CreateDigitalInterruptPort(IPin pin, InterruptMode interruptMode, ResistorMode resistorMode, TimeSpan debounceDuration, TimeSpan glitchDuration)

Returns

Meadow.Hardware.IDigitalInterruptPort: IDigitalInterruptPort

Parameters

Type	Name	Description
Meadow.Hardware.IPin	pin	The pin representing the port
Meadow.Hardware.InterruptMode	interruptMode	The port interrupt mode
Meadow.Hardware.ResistorMode	resistorMode	The port resistor mode
System.TimeSpan	debounceDuration	The debounce duration
System.TimeSpan	glitchDuration	The glitch duration - not configurable on Mcp23xxx

SetPortDirection(IPin, PortDirectionType)

Sets the direction of a port

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Declaration

public void SetPortDirection(IPin pin, PortDirectionType direction)

Parameters

Type	Name	Description
Meadow.Hardware.IPin	pin	The pin representing the port
Meadow.Hardware.PortDirectionType	direction	The port direction (input or output)

WriteToPort(IPin, bool)

Sets a particular pin's value. If that pin is not in output mode, this method will first set its mode to output.

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Declaration

public void WriteToPort(IPin pin, bool value)

Parameters

Type	Name	Description
Meadow.Hardware.IPin	pin	The pin to write to.
System.Boolean	value	The value to write. True for high, false for low.

ReadPort(IPin)

Gets the value of a particular port. If the port is currently configured as an output, this will change the configuration.

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Declaration

public bool ReadPort(IPin pin)

Returns

System.Boolean

Parameters

Type	Name
Meadow.Hardware.IPin	pin

WriteToPorts(byte)

Outputs a byte value across all of the pins by writing directly to the output latch (OLAT) register

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Declaration

public void WriteToPorts(byte mask)

Parameters

Type	Name
System.Byte	mask

ReadFromPorts(PortBank)

Reads a byte value from all of the pins. little-endian; the least significant bit is the value of GP0. So a byte value of 0x60, or 0110 0000, means that pins GP5 and GP6 are high.

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Declaration

public byte ReadFromPorts(Mcp23xxx.PortBank bank = PortBank.A)

Returns

System.Byte: A little-endian byte mask of the pin values.

Parameters

Type	Name
Meadow.Foundation.ICs.IOExpanders.Mcp23xxx.PortBank	bank

ResetPin(IPin)

Sets the pin back to an input

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Declaration

protected void ResetPin(IPin pin)

Parameters

Type	Name
Meadow.Hardware.IPin	pin

GetPin(string)

Get Pin by name

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Declaration

public abstract IPin GetPin(string pinName)

Returns

Meadow.Hardware.IPin: IPin object if found

Parameters

Type	Name	Description
System.String	pinName	The pin name

Events

InputChanged

Raised when the value of any pin configured for input interrupts changes This provides raw port state data from the MCP23xxx It's highly recommended to prefer using the events exposed on the digital input ports instead.

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Declaration

public event EventHandler<IOExpanderInputChangedEventArgs> InputChanged

Event Type

System.EventHandler<Meadow.Foundation.ICs.IOExpanders.IOExpanderInputChangedEventArgs>

Implements

• Meadow.Hardware.IDigitalInputOutputController
• Meadow.Hardware.IDigitalInputController
• Meadow.Hardware.IDigitalOutputController
• Meadow.Hardware.ISpiPeripheral
• Meadow.Hardware.II2cPeripheral
• Meadow.Hardware.IDigitalInterruptController
• Meadow.Hardware.IPinController