com.oracle.deviceaccess.gpio
Interface GPIOPin

All Superinterfaces:

Peripheral

public interface GPIOPin
extends Peripheral

Interface for GPIO pin.

Application can access each GPIO pin through this interface. Each GPIO pin has its own ID. ID is integer value.

Application can obtain value of current GPIO pin by using getValue() method and set specific value to GPIO pin by using setValue(boolean) method.

Hint may be used for getting more detailed information about given GPIO pin. For example, If button for toggling LED is attached to "pin10". then OEM can assign hint as "LED switch". this can be used for generating more readable source code.

Application can read value from pin by using polling. but event driven way (interrupt) is also supported by registering listener for GPIO pin.In order to use interrupt. first, application implement PinListener and then register it with setInputListener() method. then notification begins. application can stop notification and remove listener by calling removeInputListener().Listener can be set just only for input pin.this means interrupt is only supported by input pins. If try to set listener to output pins then it will get InvalidOperationException

Listener for GPIO port is also available.

 class GPIOInterruptTest implement PinListener{
  ...
   public void startRead(){
       GPIOPin pin = GPIO.getPin(pinID);
     
       pin.setInputListener(this);
   }
   ...
   void valueChanged(GPIOPin pin,boolean value){
      System.out.println("pin value" + value);
   }
...
}

 

Application should return GPIOPin by calling release() method of Peripheral interface when GPIOPin is no longer used.

Field Summary

static int	INPUT
static int	OUTPUT

Method Summary

int	getDirection() Returns the current direction of pin.
boolean	getValue() Returns the current value of the pin, this can be called on both outputs and inputs.
void	setDirection(int direction) Set the current direction of pin.
void	setInputListener(PinListener listener) Register listener for receiving callback from input pin.
void	setValue(boolean value) Set pin value.

Methods inherited from interface com.oracle.deviceaccess.Peripheral

close, getID, getName

Field Detail

INPUT

static final int INPUT

See Also:

Constant Field Values

OUTPUT

static final int OUTPUT

See Also:

Constant Field Values

Method Detail

getValue

boolean getValue()
                 throws java.io.IOException,
                        PeripheralNotAvailableException

Returns the current value of the pin, this can be called on both outputs and inputs.

Returns:

true if pin is currently high

Throws:

java.lang.SecurityException - throws when application has not enough permission.

java.io.IOException - error occured while writing data to port.

PeripheralNotAvailableException

setValue

void setValue(boolean value)
              throws java.io.IOException,
                     PeripheralNotAvailableException

Set pin value. InvalidOperationException will be thrown if try to set value to output pin.

Parameters:

value - binary value

Throws:

java.lang.SecurityException - throws when application has not enough permission.

java.io.IOException - error occured while writing data to port.

PeripheralNotAvailableException

getDirection

int getDirection()
                 throws java.io.IOException,
                        PeripheralNotAvailableException

Returns the current direction of pin. Check whether current pin is output pin or input pin.

Returns:

OUTPUT or INPUT

Throws:

java.io.IOException

PeripheralNotAvailableException

setDirection

void setDirection(int direction)
                  throws PeripheralNotAvailableException,
                         java.io.IOException

Set the current direction of pin. Change the direction of current GPIO pin.

Parameters:

direction - OUTPUT for output pin and INPUT for input pin

Throws:

java.lang.SecurityException - throws when application has not enough permission.

PeripheralNotAvailableException

java.io.IOException

setInputListener

void setInputListener(PinListener listener)
                      throws PeripheralNotAvailableException

Register listener for receiving callback from input pin. Notification will be automatically begin after registering completed.
InvalidOperationException will be thrown if try to set listener to output pin. If try to register listener when another listener is already registered then the second call for this method will override first one.

Parameters:

listener - Listener for this pin.ad

Throws:

java.lang.SecurityException - throws when application has not enough permission.

PeripheralNotAvailableException