com.digi.android.gpio

Class GPIO

java.lang.Object

com.digi.android.gpio.GPIO

public class GPIO
extends java.lang.Object

Represents a GPIO (General Purpose Input/Output) module pin.

A GPIO lets you configure and control a physical module or board pin being able to write and read its value.

To obtain an instance of the GPIO you have to use one of the following methods:

• GPIOManager.createGPIO(int, GPIOMode)
• GPIOManager.createGPIO(int, int, GPIOMode)

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_POLLING_RATE Default polling rate: 100 milliseconds.

Method Summary

Modifier and Type	Method and Description
protected void	finalize()
int	getKernelNumber() Retrieves the kernel number associated to this GPIO object.
GPIOMode	getMode() Retrieves the GPIO working mode.
int	getPinIndex() Retrieves the pin index associated to this GPIO object.
int	getPollingRate() Retrieves the polling rate time configured for this GPIO.
int	getPortIndex() Retrieves the base port index associated to this GPIO object.
GPIOValue	getValue() Retrieves the GPIO value.
void	registerListener(IGPIOListener listener) Registers a listener to detect when a GPIO changes value.
void	setMode(GPIOMode mode) Sets the GPIO working mode.
void	setPollingRate(int pollingRate) Configures the polling rate time for this GPIO.
void	setValue(GPIOValue value) Sets the GPIO value.
java.lang.String	toString() Returns a string representation of this GPIO.
void	unregisterListener(IGPIOListener listener) Unregisters a listener to stop detecting when a GPIO changes value.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_POLLING_RATE

public static final int DEFAULT_POLLING_RATE

Default polling rate: 100 milliseconds.

See Also:

Constant Field Values

Method Detail

getValue

public GPIOValue getValue()
                   throws GPIOException

Retrieves the GPIO value.

Attempts to read the GPIO value file and retrieve the contents.

This method only has effect if GPIO mode is:

• GPIOMode.INPUT
• GPIOMode.INTERRUPT_EDGE_RISING
• GPIOMode.INTERRUPT_EDGE_FALLING
• GPIOMode.INTERRUPT_EDGE_BOTH

For modes GPIOMode.OUTPUT_HIGH and GPIOMode.OUTPUT_LOW this method always returns GPIOValue.LOW.

Returns:

The GPIO value.

Throws:

GPIOException - If there is an error reading the GPIO value.

See Also:

setValue(GPIOValue), GPIOValue.HIGH, GPIOValue.LOW

setValue

public void setValue(GPIOValue value)
              throws GPIOException

Sets the GPIO value.

Attempts to write in the GPIO value file.

This method only has effect if GPIO mode is:

• GPIOMode.OUTPUT_HIGH
• GPIOMode.OUTPUT_LOW

For modes GPIOMode.INPUT, GPIOMode.INTERRUPT_EDGE_RISING, GPIOMode.INTERRUPT_EDGE_FALLING and GPIOMode.INTERRUPT_EDGE_BOTH this method returns without further action.

Parameters:

value - New GPIO value.

Throws:

GPIOException - If there is an error setting the GPIO value.

java.lang.NullPointerException - If value == null.

See Also:

getValue(), setMode(GPIOMode), GPIOValue.HIGH, GPIOValue.LOW

getMode

public GPIOMode getMode()

Retrieves the GPIO working mode.

Returns:

The GPIO configured mode.

See Also:

setMode(GPIOMode), GPIOMode.INPUT, GPIOMode.INTERRUPT_EDGE_BOTH, GPIOMode.INTERRUPT_EDGE_FALLING, GPIOMode.INTERRUPT_EDGE_RISING, GPIOMode.OUTPUT_HIGH, GPIOMode.OUTPUT_LOW

setMode

public void setMode(GPIOMode mode)
             throws GPIOException

Sets the GPIO working mode.

Configures required GPIO edge and direction values to set the GPIO in the given working mode.

Parameters:

mode - The desired GPIO working mode.

Throws:

GPIOException - If the given mode is not valid or if there is an error setting the GPIO direction or edge.

java.lang.NullPointerException - If mode == null.

See Also:

getMode(), GPIOMode.INPUT, GPIOMode.INTERRUPT_EDGE_BOTH, GPIOMode.INTERRUPT_EDGE_FALLING, GPIOMode.INTERRUPT_EDGE_RISING, GPIOMode.OUTPUT_HIGH, GPIOMode.OUTPUT_LOW

getKernelNumber

public int getKernelNumber()

Retrieves the kernel number associated to this GPIO object.

Returns:

The kernel number.

getPortIndex

public int getPortIndex()

Retrieves the base port index associated to this GPIO object.

Returns:

The base port index.

getPinIndex

public int getPinIndex()

Retrieves the pin index associated to this GPIO object.

Returns:

The pin index.

registerListener

public void registerListener(IGPIOListener listener)

Registers a listener to detect when a GPIO changes value.

If the given listener is already registered, this method does nothing.

Parameters:

listener - The listener to be registered.

Throws:

java.lang.NullPointerException - If listener == null.

See Also:

unregisterListener(IGPIOListener), IGPIOListener

unregisterListener

public void unregisterListener(IGPIOListener listener)

Unregisters a listener to stop detecting when a GPIO changes value.

If the given listener is not registered, this method does nothing.

Parameters:

listener - The listener to be unregistered.

Throws:

java.lang.NullPointerException - If listener == null.

See Also:

registerListener(IGPIOListener), IGPIOListener

setPollingRate

public void setPollingRate(int pollingRate)

Configures the polling rate time for this GPIO.

The polling rate stands for the amount of milliseconds between checks for changes in the GPIO value.

Note: Depending on the configured polling rate changes may not be detected if they occur between checks.

 
 
 HIGH................__________.................
                    |          |
 LOW _______________|          |________________
           ^                             ^
           |                             |
           +-----------------------------+
                  Polling rate time
 
 

Parameters:

pollingRate - Time in milliseconds to wait between each interruption triggered check.

Throws:

java.lang.IllegalArgumentException - If pollingRate < 0.

See Also:

getPollingRate()

getPollingRate

public int getPollingRate()

Retrieves the polling rate time configured for this GPIO.

The polling rate stands for the amount of milliseconds between which thread will check for interrupt event.

The default polling rate is 100 milliseconds.

Returns:

The configured polling rate.

See Also:

setPollingRate(int)

toString

public java.lang.String toString()

Returns a string representation of this GPIO.

Currently this is a string indicating the GPIO kernel number, its port and pin indexes and how it is configured.

You can get these values separately using getKernelNumber(), getPortIndex(), getPinIndex(), and getMode().

Overrides:

toString in class java.lang.Object

Returns:

String representation of this GPIO.

finalize

protected void finalize()
                 throws java.lang.Throwable

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable