dioscuri.module.pit
Class Counter

java.lang.Object
  dioscuri.module.pit.Counter

public class Counter
extends java.lang.Object

A single counter of the PIT based on the Intel 82C54 chipset.

This counter works following the convention rules of the PIT: 1. For each counter, the control word must be written before the initial count is written. 2. The initial count must follow the count format specified in the Control Word (LSB, MSB, etc.)

Field Summary

protected boolean	bcd
protected byte[]	ce
protected int	counterMode
protected byte[]	cr
protected static int	LSB
protected static int	MSB
protected byte[]	ol
protected boolean	readBackCmd
protected int	rwMode

Constructor Summary

Counter(PIT pit, int counterNumber)
Constructor of the counter class

Method Summary

void	clockPulse() Performs counter action on one clockpulse.
protected boolean	getBCD() Return if this counter is in BCD mode
protected int	getCounterNumber() Return the counter number (ID)
protected byte	getCounterValue() Returns the counter value depending on the R/W mode
protected boolean	getGateSignal() Retrieves the GATE signal
protected boolean	getOutSignal() Retrieves the OUT signal
protected boolean	getParity() Return the parity of the count value
protected boolean	isEnabled() Return if this counter has been enabled
protected void	latchCounter() Latch this counter (read back current count value) Note: this function only works if the counter is in latchmode.
protected void	setCounterMode(int mode) Set counter mode
protected void	setCounterValue(byte data) Set counter value depending on the R/W mode Note: it is assumed that data is always loaded in LSB, MSB order.
protected void	setEnabled(boolean status) Enable/disable the counter
protected void	setGateSignal(boolean status) Sets the GATE signal to given status GATE signal is compared with its previous state.

Methods inherited from class java.lang.Object

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

Field Detail

counterMode

protected int counterMode

rwMode

protected int rwMode

bcd

protected boolean bcd

ce

protected byte[] ce

cr

protected byte[] cr

ol

protected byte[] ol

readBackCmd

protected boolean readBackCmd

LSB

protected static final int LSB

See Also:

Constant Field Values

MSB

protected static final int MSB

See Also:

Constant Field Values

Constructor Detail

Counter

public Counter(PIT pit,
               int counterNumber)

Constructor of the counter class

Parameters:

pit -

counterNumber -

Method Detail

clockPulse

public void clockPulse()

Performs counter action on one clockpulse. The action depends on the mode the counter is set to, the GATE signal, R/W mode and BCD setting.

getGateSignal

protected boolean getGateSignal()

Retrieves the GATE signal

Returns:

boolean true if GATE is high, false if GATE is low

setGateSignal

protected void setGateSignal(boolean status)

Sets the GATE signal to given status GATE signal is compared with its previous state. If GATE is rising (low -> high), variable isGateRising is set to true If GATE is falling (high -> low), signal OUT is turned high immediately for some counter modes

Parameters:

status -

getOutSignal

protected boolean getOutSignal()

Retrieves the OUT signal

Returns:

boolean true if OUT is high, false if OUT is low

getCounterValue

protected byte getCounterValue()

Returns the counter value depending on the R/W mode

Returns:

byte data containing the LSB/MSB from Counting Element (ce) or Output latch (ol)

setCounterValue

protected void setCounterValue(byte data)

Set counter value depending on the R/W mode Note: it is assumed that data is always loaded in LSB, MSB order. So, first LSB then MSB.

Parameters:

data -

setCounterMode

protected void setCounterMode(int mode)

Set counter mode

Parameters:

mode -

latchCounter

protected void latchCounter()

Latch this counter (read back current count value) Note: this function only works if the counter is in latchmode. The latched value is stored in register ol.

getParity

protected boolean getParity()

Return the parity of the count value

Returns:

boolean true=EVEN, false=ODD

getBCD

protected boolean getBCD()

Return if this counter is in BCD mode

Returns:

boolean true=BCD, false=decimal

setEnabled

protected void setEnabled(boolean status)

Enable/disable the counter

Parameters:

status -

isEnabled

protected boolean isEnabled()

Return if this counter has been enabled

Returns:

true if enabled, false otherwise

getCounterNumber

protected int getCounterNumber()

Return the counter number (ID)

Returns:

int counternumber