com.pi4j.gpio.extension.mcp

Class MCP3x0xGpioProvider

java.lang.Object

com.pi4j.io.gpio.GpioProviderBase

com.pi4j.gpio.extension.base.AdcGpioProviderBase

com.pi4j.gpio.extension.mcp.MCP3x0xGpioProvider

All Implemented Interfaces:

AdcGpioProvider, GpioProvider

Direct Known Subclasses:

MCP3004GpioProvider, MCP3008GpioProvider, MCP3204GpioProvider, MCP3208GpioProvider

public abstract class MCP3x0xGpioProvider
extends AdcGpioProviderBase
implements GpioProvider

This GPIO provider implements the base functionality for the MCP3004 & MCP3008 & MCP3204 & MCP3208 SPI ADC as native Pi4J GPIO pins. It is a 10-bit ADC providing between 4 and 8 input channels. More information about the ADC chip can be found here: http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf

The MCP3x0x family is connected via SPI connection to the Raspberry Pi and provides 4/8 GPIO pins that can be used for analog input pins. The values returned are in the range from 0 to the highest number (e.g. 1023 or 4095) depending on the ADC resolution. Note: This implementation currently only supports single-ended inputs.

Author:

Robert Savage, pojd, Hendrik Motza

Field Summary

Fields

Modifier and Type	Field and Description
int	MAX_VALUE
int	MIN_VALUE
int	RESOLUTION

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

allPins, conversionDelay, monitor, monitorInterval, threshold

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

cache, DEFAULT_CACHE_SIZE, isshutdown, listeners

Fields inherited from interface com.pi4j.gpio.extension.base.AdcGpioProvider

DEFAULT_MONITOR_INTERVAL, DEFAULT_THRESHOLD, INVALID_VALUE, MIN_MONITOR_INTERVAL

Constructor Summary

Constructors

Constructor and Description
MCP3x0xGpioProvider(Pin[] pins, SpiChannel channel, int speed, int resolution, SpiMode mode) Create new instance of this MCP3x0x provider.

Method Summary

Modifier and Type	Method and Description
double	getImmediateValue(Pin pin) This method will perform an immediate data acquisition directly to the ADC chip to get the requested pin's input conversion value.
double	getMaxSupportedValue() Get the maximum supported analog value for the ADC implementation.
double	getMinSupportedValue() Get the minimum supported analog value for the ADC implementation.

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

getEventThreshold, getEventThreshold, getImmediateValue, getMonitorEnabled, getMonitorInterval, getPercentValue, getPercentValue, getValue, setEventThreshold, setEventThreshold, setMonitorEnabled, setMonitorInterval, shutdown

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

addListener, dispatchPinAnalogValueChangeEvent, dispatchPinDigitalStateChangeEvent, export, export, getMode, getName, getPinCache, getPullResistance, getPwm, getState, hasPin, isExported, isShutdown, removeAllListeners, removeListener, setMode, setPullResistance, setPwm, setPwmRange, setState, setValue, 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.io.gpio.GpioProvider

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

Field Detail

MAX_VALUE

public final int MAX_VALUE

MIN_VALUE

public final int MIN_VALUE

See Also:

Constant Field Values

RESOLUTION

public final int RESOLUTION

Constructor Detail

MCP3x0xGpioProvider

public MCP3x0xGpioProvider(Pin[] pins,
                           SpiChannel channel,
                           int speed,
                           int resolution,
                           SpiMode mode)
                    throws IOException

Create new instance of this MCP3x0x provider. Optionally enable or disable background monitoring and pin notification events.

Parameters:

pins - the collection of all GPIO pins used with this ADC provider implementation

channel - spi channel the MCP3x0x is connected to

speed - spi speed to communicate with MCP3x0x

mode - spi mode to communicate with MCP3x0x

Throws:

IOException - if an error occurs during initialization of the SpiDevice

Method Detail

getImmediateValue

public double getImmediateValue(Pin pin)
                         throws IOException

This method will perform an immediate data acquisition directly to the ADC chip to get the requested pin's input conversion value.

Specified by:

getImmediateValue in interface AdcGpioProvider

Specified by:

getImmediateValue in class AdcGpioProviderBase

Parameters:

pin - requested input pin to acquire conversion value

Returns:

conversion value for requested analog input pin

Throws:

IOException

getMinSupportedValue

public double getMinSupportedValue()

Get the minimum supported analog value for the ADC implementation.

Specified by:

getMinSupportedValue in interface AdcGpioProvider

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 AdcGpioProvider

Returns:

Returns the maximum supported analog value.