avrora.sim
Class ClockPrescaler

java.lang.Object
  avrora.sim.Clock
      avrora.sim.ClockPrescaler

public class ClockPrescaler

extends Clock

The ClockPrescaler class represents a clock that is another clock scaled appropriately; e.g. 8x slower.

Field Summary

protected long	base The base field stores the cycle count of the underlying clock at the last time that this clock was reset.
protected int	divider The divider stores the number of cycles of the underlying clock are equivalent to one cycle of this clock.
protected Clock	driveClock The driveClock field stores a reference to the clock that the prescaler is derived from.
protected long	ticksBeforeBase The ticksBeforeBase field stores the number of ticks that were recorded before the prescaler was reset.

Fields inherited from class avrora.sim.Clock

hz, name

Constructor Summary

ClockPrescaler(java.lang.String n, Clock drive, int divider)
The constructor of the ClockPrescaler creates a new clock that is an integer multiple slower than the clock that it is derived from.

Method Summary

long	getCount() The getCount() method returns the number of clock cycles (ticks) that have elapsed for this clock.
long	getTotalCount() The getTotalCount() method returns the total number of clock cycles (ticks) that have elapsed 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.
void	reset() The reset() method resets the internal clock prescaler to zero.

Methods inherited from class avrora.sim.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 the prescaler is derived from.

divider

protected final int divider

The divider stores the number of cycles of the underlying clock are equivalent to one cycle of this clock. For example, with a divider or 8, the underlying clock ticks 8 times for each tick of this clock.

base

protected long base

The base field stores the cycle count of the underlying clock at the last time that this clock was reset.

ticksBeforeBase

protected long ticksBeforeBase

The ticksBeforeBase field stores the number of ticks that were recorded before the prescaler was reset. This is used in the calculation of the total number of ticks that have elapsed.

Constructor Detail

ClockPrescaler

public ClockPrescaler(java.lang.String n,
                      Clock drive,
                      int divider)

The constructor of the ClockPrescaler creates a new clock that is an integer multiple slower than the clock that it is derived from. Additionally, the phase at which this clock fires can be adjusted by resetting.

Parameters:

n - the name of the new clock

drive - the clock that drives this derived clock

divider - the muliple by which the derived clock is slower than the source

Method Detail

getCount

public long getCount()

The getCount() method returns the number of clock cycles (ticks) that have elapsed for this clock. In the implementation of the ClockPrescaler, this method calculates the number of scaled cycles since the last reset.

Specified by:

getCount in class Clock

Returns:

the number of elapsed time ticks in clock cycles

getTotalCount

public long getTotalCount()

The getTotalCount() method returns the total number of clock cycles (ticks) that have elapsed for this clock. In the implementation of the ClockPrescaler, this method calculates the number of scaled cycles since the last reset, plus the number of ticks elapsed before the reset.

Returns:

the number of elapsed time ticks in clock cycles

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. In the implementation of ClockPrescaler, the event will be scheduled in the underlying clock, with the delay calculated correctly from the last time that the prescaler was reset.

Specified by:

insertEvent in class Clock

Parameters:

e - the event to be inserted

delta - the number of (scaled) cycles in the future at which to fire

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

reset

public void reset()

The reset() method resets the internal clock prescaler to zero. Thus, the prescaler's previous phase is broken, and the clock signal continues with the same frequency, only that the first tick will happen divider cycles from now.