Describes the input and output functions involved in implementing the GPIO interface class.
There is no general reason why a pin which is available for use for GPIO should not also be available for some other function, and the GPIO interface specification allows for this. There are certain circumstances where pin sharing should be prevented, for instance when a pin is in use as an interrupt source, and these cases are specified individually.
Implement SetOutputState() for
each value of TGpioState.
Implement SetOutputState() with aState == ELow and return value KErrNone.
Verify that the pin is being used as a binary output. Set it to its low electric state.
Implement SetOutputState() with aState == EHigh and return value KErrNone.
Verify that the pin is being used as a binary output. Set it to its high electric state.
Implement SetOutputState() with aState == EDefaultIdleState and return value KErrNone.
Verify that the pin is being used as a binary output. Set its electric state to its default idle state.
Implement SetOutputState() with return value KErrNotSupported.
If the specified electric
state is not supported return KErrNotSupported.
Implement GetOutputState() with
return value KErrNone.
Verify that the pin is being used as a binary output. Determine
its electric state and set aState to the
appropriate value of TGpioState.
Implement GetInputState() with
return value KErrNone.
Verify that the pin is being used as a binary input. Determine
its electric state and set aState to the
appropriate value of TGpioState.