avrora.sim.clock
Class DerivedClock

java.lang.Object
  avrora.sim.clock.Clock
      avrora.sim.clock.DerivedClock

public class DerivedClock

extends Clock

The DerivedClock class represents a clock that is derived from another clock; i.e. the derived clock runs slower but is synchronized with the clock that it is derived from. An example is the 32khz real time clock on the Mica2--it runs independently of the main clock, but in the simulation, it uses the main clock signal to synchronize its execution to the execution of the program.

Field Summary

protected double	divider The divider stores a the ration between the clockspeed of the drive clock and the clockspeed of this clock.
protected Clock	driveClock The driveClock field stores a reference to the clock that is underlying this derived clock.

Fields inherited from class avrora.sim.clock.Clock

hz, name

Constructor Summary

DerivedClock(java.lang.String n, Clock driver, long hz)
The constructor of the DerivedClock creates a new clock with the specified name, driven by the specified clock, with the specified clockrate.

Method Summary

long	getCount() The getCount() method returns the total count of clock ticks that have happened for this clock.
void	insertEvent(Simulator.Event e, long delta) The insertEvent() method inserts an event into the event queue of the clock with the specified delay in clock cycles.
void	removeEvent(Simulator.Event e) The removeEvent() method removes an event from the event queue of the clock.

Methods inherited from class avrora.sim.clock.Clock

getHZ, getName

Methods inherited from class java.lang.Object

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

Field Detail

driveClock

protected final Clock driveClock

The driveClock field stores a reference to the clock that is underlying this derived clock.

divider

protected final double divider

The divider stores a the ration between the clockspeed of the drive clock and the clockspeed of this clock.

Constructor Detail

DerivedClock

public DerivedClock(java.lang.String n,
                    Clock driver,
                    long hz)

The constructor of the DerivedClock creates a new clock with the specified name, driven by the specified clock, with the specified clockrate. The derived clock can have any speed that is slower than the clock that it is derived from. Roundoff errors will happen when the rates are not an integer multiple of each other, but are guaranteed never to exceed 1 cycle of the underlying clock.

Parameters:

n - the name of the clock

driver - the clock source from which this clock is derived

hz - the number of cycles per second of this clock

Method Detail

getCount

public long getCount()

The getCount() method returns the total count of clock ticks that have happened for this clock. Since this clock is a derived clock, it computes the number of clock cycles that have happened based on the number of clock cycles that have happened for the underlying clock from which it is derived.

Specified by:

getCount in class Clock

Returns:

the count in cycles of this clock

insertEvent

public void insertEvent(Simulator.Event e,
                        long delta)

The insertEvent() method inserts an event into the event queue of the clock with the specified delay in clock cycles. The event will then be executed at the future time specified.

Specified by:

insertEvent in class Clock

Parameters:

e - the event to be inserted

delta - the number of cycles in the future at which to event

removeEvent

public void removeEvent(Simulator.Event e)

The removeEvent() method removes an event from the event queue of the clock. The comparison used is reference equality, not .equals().

Specified by:

removeEvent in class Clock

Parameters:

e - the event to remove