com.pi4j.gpio.extension.mcp

Class MCP4725GpioProvider

java.lang.Object

com.pi4j.io.gpio.GpioProviderBase

com.pi4j.gpio.extension.base.DacGpioProviderBase

com.pi4j.gpio.extension.mcp.MCP4725GpioProvider

All Implemented Interfaces:

DacGpioProvider, GpioProvider

public class MCP4725GpioProvider
extends DacGpioProviderBase
implements DacGpioProvider

This GPIO provider implements the MCP4725 12-Bit Digital-to-Analog Converter as native Pi4J GPIO pins. More information about the board can be found here: http://www.adafruit.com/product/935 Data Sheet: http://www.adafruit.com/datasheets/mcp4725.pdf

The MCP4725 is connected via SPI connection to the Raspberry Pi and provides 1 GPIO analog output pin.

Author:

Christian Wehrli, Robert Savage

Field Summary

Fields

Modifier and Type	Field and Description
static String	DESCRIPTION
static int	MAX_VALUE
static int	MCP4725_ADDRESS_1
static int	MCP4725_ADDRESS_2
static int	MIN_VALUE
static String	NAME

Fields inherited from class com.pi4j.gpio.extension.base.DacGpioProviderBase

allPins, shutdownValues

Fields inherited from class com.pi4j.io.gpio.GpioProviderBase

cache, DEFAULT_CACHE_SIZE, isshutdown, listeners

Constructor Summary

Constructors

Constructor and Description
MCP4725GpioProvider(I2CBus bus, int address) This is an alternate constructor that can be used to create the MCP4725 instance but not be considered the I2C bus owner and the class will not close the bus communication when the class is destroyed or on program shutdown.
MCP4725GpioProvider(int busNumber, int address) This is the default constructor.

Method Summary

Modifier and Type	Method and Description
double	getMaxSupportedValue() Get the maximum supported analog value for the ADC implementation.
double	getMinSupportedValue() Get the minimum supported analog value for the ADC implementation.
String	getName() Gets the name of the DAC provider instance.
void	setValue(Pin pin, double value) Set the analog output value to an output pin on the DAC immediately.
void	shutdown() This method is used by the framework to shutdown the DAC instance and apply any configured shutdown values to the DAC pins.

Methods inherited from class com.pi4j.gpio.extension.base.DacGpioProviderBase

getShutdownValue, getShutdownValue, setPercentValue, setPercentValue, setShutdownValue, setShutdownValue, setValue

Methods inherited from class com.pi4j.io.gpio.GpioProviderBase

addListener, dispatchPinAnalogValueChangeEvent, dispatchPinDigitalStateChangeEvent, export, export, getMode, getPinCache, getPullResistance, getPwm, getState, getValue, hasPin, isExported, isShutdown, removeAllListeners, removeListener, setMode, setPullResistance, setPwm, setPwmRange, setState, unexport

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.pi4j.gpio.extension.base.DacGpioProvider

getShutdownValue, getShutdownValue, setPercentValue, setPercentValue, setShutdownValue, setShutdownValue, setValue

Methods inherited from interface com.pi4j.io.gpio.GpioProvider

addListener, export, export, getMode, getPullResistance, getPwm, getState, getValue, hasPin, isExported, isShutdown, removeAllListeners, removeListener, setMode, setPullResistance, setPwm, setPwmRange, setState, unexport

Field Detail

NAME

public static final String NAME

See Also:

Constant Field Values

DESCRIPTION

public static final String DESCRIPTION

See Also:

Constant Field Values

MAX_VALUE

public static final int MAX_VALUE

See Also:

Constant Field Values

MIN_VALUE

public static final int MIN_VALUE

See Also:

Constant Field Values

MCP4725_ADDRESS_1

public static final int MCP4725_ADDRESS_1

See Also:

Constant Field Values

MCP4725_ADDRESS_2

public static final int MCP4725_ADDRESS_2

See Also:

Constant Field Values

Constructor Detail

MCP4725GpioProvider

public MCP4725GpioProvider(int busNumber,
                           int address)
                    throws I2CFactory.UnsupportedBusNumberException,
                           IOException

This is the default constructor. If you use this constructor the MCP4725 will be considered the I2C bus owner and will close the bus communication any time the class is destroyed and on program shutdown.

Parameters:

busNumber - the I2C bus number used to communicate with the MCP4725

address - the address of the MCP4725 on the I2C bus.

Throws:

IOException

I2CFactory.UnsupportedBusNumberException

MCP4725GpioProvider

public MCP4725GpioProvider(I2CBus bus,
                           int address)
                    throws IOException

This is an alternate constructor that can be used to create the MCP4725 instance but not be considered the I2C bus owner and the class will not close the bus communication when the class is destroyed or on program shutdown.

Parameters:

bus - an existing I2C bus instance defined in the user's code to communicate with the MCP4725

address - the address of the MCP4725 on the I2C bus.

Throws:

IOException

Method Detail

setValue

public void setValue(Pin pin,
                     double value)

Set the analog output value to an output pin on the DAC immediately.

Specified by:

setValue in interface GpioProvider

Overrides:

setValue in class GpioProviderBase

Parameters:

pin - analog output pin

value - raw value to send to the DAC. (Between: 0..4095)

getName

public String getName()

Gets the name of the DAC provider instance.

Specified by:

getName in interface GpioProvider

Specified by:

getName in class GpioProviderBase

Returns:

name of the DAC provider instance.

shutdown

public void shutdown()

This method is used by the framework to shutdown the DAC instance and apply any configured shutdown values to the DAC pins. This method will also close the I2C bus for the connected MCP4725.

Specified by:

shutdown in interface GpioProvider

Overrides:

shutdown in class DacGpioProviderBase

getMinSupportedValue

public double getMinSupportedValue()

Get the minimum supported analog value for the ADC implementation.

Specified by:

getMinSupportedValue in interface DacGpioProvider

Returns:

Returns the minimum supported analog value.

getMaxSupportedValue

public double getMaxSupportedValue()

Get the maximum supported analog value for the ADC implementation. (For example, a 10 bit ADC's maximum value is 1023 and a 12-bit ADC's maximum value is 4095.

Specified by:

getMaxSupportedValue in interface DacGpioProvider

Returns:

Returns the maximum supported analog value.