dioscuri.module.pit
Class PIT

java.lang.Object
  dioscuri.module.AbstractModule
      dioscuri.module.ModulePIT
          dioscuri.module.pit.PIT

All Implemented Interfaces:

Addressable, Module, Updateable

public class PIT
extends ModulePIT

An implementation of a Programmable Interval Timer (PIT) module based on the Intel 82C54 PIT chip.

See Also:

Metadata module ******************************************** general.type : pit general.name : Programmable Interval Timer (PIT) based on Intel 82C54 PIT general.architecture : Von Neumann general.description : Implements the Intel 82C54 PIT extended with a system clock general.creator : Tessella Support Services, Koninklijke Bibliotheek, Nationaal Archief of the Netherlands general.version : 1.0 general.keywords : pit, timer, counter general.relations : motherboard, cpu general.yearOfIntroduction : 1994 general.yearOfEnding : general.ancestor : Intel 8253 general.successor : pit.numberOfCounters : 3 pit.numberOfModes : 6 pit.clockFrequency : 1193181 (ideally, but maybe not feasible in Java)

Notes: This PIT is implemented to be as close as possible to the functional behaviour of an original Intel 82C54. However, not all logic has to be implemented. Not part of this implementation is: - Signal lines WR, RD, CD, A0 and A1.

Normally counters 0,1,2 are defined to a particular task (RTC, etc.). In this implementation counter zero generates a IRQ 0 if the count becomes zero. Other counters are not assigned.

In the original PIT, the clock signal is generated by a separate hardware component (crystal). In the emulated PIT, the clock signal is generated by a separate moduleClock (imitates the crystal, but may have a different frequency).

Nested Class Summary

Nested classes/interfaces inherited from interface dioscuri.interfaces.Module

Module.Type

Field Summary

protected int

irqNumber

Fields inherited from class dioscuri.module.AbstractModule

type

Constructor Summary

PIT(Emulator owner)
Class constructor

Method Summary

java.lang.String	getDump() Return a dump of module status
byte	getIOPortByte(int portAddress)
byte[]	getIOPortDoubleWord(int portAddress)
byte[]	getIOPortWord(int portAddress)
int	getUpdateInterval() Get the update interval.
protected void	lowerIRQ(Counter counter)
protected void	raiseIRQ(Counter counter)
boolean	reset() Reset all parameters of module.
void	setIOPortByte(int portAddress, byte data)
void	setIOPortDoubleWord(int portAddress, byte[] dataDoubleWord)
void	setIOPortWord(int portAddress, byte[] dataWord)
void	setUpdateInterval(int interval) Defines the interval between subsequent updates
void	update() Update the module.

Methods inherited from class dioscuri.module.AbstractModule

getConnection, getConnections, getDebugMode, getExpectedConnections, getType, isConnected, setConnection, setDebugMode, start, stop

Methods inherited from class java.lang.Object

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

Methods inherited from interface dioscuri.interfaces.Module

getConnection, getConnections, getDebugMode, getExpectedConnections, getType, isConnected, setConnection, setDebugMode, start, stop

Field Detail

irqNumber

protected int irqNumber

Constructor Detail

PIT

public PIT(Emulator owner)

Class constructor

Parameters:

owner -

Method Detail

reset

public boolean reset()

Reset all parameters of module.

Specified by:

reset in interface Module

Specified by:

reset in class AbstractModule

Returns:

true iff the AbstractModule was reset properly.

See Also:

AbstractModule

getDump

public java.lang.String getDump()

Return a dump of module status

Provides a dummy implementation since many of the subclasses of this abstract module class do not need or use a getDump() implementation. The ones that do, can override this method.

Specified by:

getDump in interface Module

Overrides:

getDump in class AbstractModule

Returns:

string containing a dump of this module

See Also:

AbstractModule

getUpdateInterval

public int getUpdateInterval()

Get the update interval.

Returns:

the update interval

See Also:

Updateable

setUpdateInterval

public void setUpdateInterval(int interval)

Defines the interval between subsequent updates

Parameters:

interval - the interval between subsequent updates in ms.

See Also:

Updateable

update

public void update()

Update the module.

See Also:

Updateable

getIOPortByte

public byte getIOPortByte(int portAddress)
                   throws ModuleException,
                          UnknownPortException

Returns:

Throws:

ModuleException

UnknownPortException

See Also:

Addressable

setIOPortByte

public void setIOPortByte(int portAddress,
                          byte data)
                   throws ModuleException,
                          UnknownPortException

Throws:

ModuleException

UnknownPortException

See Also:

Addressable

getIOPortWord

public byte[] getIOPortWord(int portAddress)
                     throws ModuleException,
                            WriteOnlyPortException

Returns:

Throws:

ModuleException

WriteOnlyPortException

See Also:

Addressable

setIOPortWord

public void setIOPortWord(int portAddress,
                          byte[] dataWord)
                   throws ModuleException

Throws:

ModuleException

See Also:

Addressable

getIOPortDoubleWord

public byte[] getIOPortDoubleWord(int portAddress)
                           throws ModuleException,
                                  WriteOnlyPortException

Returns:

Throws:

ModuleException

WriteOnlyPortException

See Also:

Addressable

setIOPortDoubleWord

public void setIOPortDoubleWord(int portAddress,
                                byte[] dataDoubleWord)
                         throws ModuleException

Throws:

ModuleException

See Also:

Addressable

raiseIRQ

protected void raiseIRQ(Counter counter)

Parameters:

counter -

lowerIRQ

protected void lowerIRQ(Counter counter)

Parameters:

counter -