io.github.robolib.module.sensor

Class Counter

java.lang.Object

io.github.robolib.module.sensor.CounterBase

io.github.robolib.module.sensor.Counter

All Implemented Interfaces:

CounterSource, PIDSource, Module, SensorModule

Direct Known Subclasses:

GearTooth

public class Counter
extends CounterBase
implements SensorModule, PIDSource

Author:

noriah

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Counter.CounterMode Modes for the counter to count in?
static class	Counter.SourceType The two different source types.

Nested classes/interfaces inherited from class io.github.robolib.module.sensor.CounterBase

CounterBase.EncodingType

Nested classes/interfaces inherited from interface io.github.robolib.identifier.PIDSource

PIDSource.PIDSourceType

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	m_allocatedDownSource
private boolean	m_allocatedUpSource
private java.nio.ByteBuffer	m_counter
private double	m_distancePerPulse
private DigitalIO	m_downSource
private int	m_index
private PIDSource.PIDSourceType	m_pidSType
private DigitalIO	m_upSource

Constructor Summary

Constructors

Constructor and Description
Counter() Create an instance of a counter where no sources are selected.
Counter(CounterBase.EncodingType eType, DigitalIO.DigitalChannel upChannel, DigitalIO.DigitalChannel downChannel, boolean inverted)
Counter(CounterBase.EncodingType eType, DigitalIO upSource, DigitalIO downSource, boolean inverted) Create an instance of a Counter object.
Counter(DigitalIO.DigitalChannel upChannel) Create an instance of a Counter object.
Counter(DigitalIO upSource) Create an instance of a counter from a Digital Input.

Method Summary

Modifier and Type	Method and Description
void	clearSource(Counter.SourceType sType) Disable the counting source to the counter.
void	disableModule() Disable the module
void	enableModule() Enable the module
void	free()
int	getCount() Read the current counter value.
boolean	getDirection() The last direction the counter value changed.
double	getDistance() Read the current scaled counter value.
boolean	getModuleEnabled()
double	getPeriod() Get the Period of the most recent count.
double	getRate() Get the current rate of the Counter.
int	getSamplesPerAverage() Get the Samples to Average which specifies the number of samples of the timer to average when calculating the period.
boolean	getStopped() Determine if the clock is stopped.
double	pidGet()
void	reset() Reset the Counter to zero.
void	setDistancePerPulse(double distance) Set the distance per pulse for this counter.
void	setExternalDirectionMode() Set external direction mode on this counter.
void	setMaxPeriod(double maxPeriod) Set the maximum period where the device is still considered "moving".
private void	setMode(Counter.CounterMode mode, java.lang.Object... args)
void	setPIDSourceType(PIDSource.PIDSourceType sType) Set which parameter of the encoder you are using as a process control variable.
void	setPulseLengthMode(double threshold) Configure the counter to count in up or down based on the length of the input pulse.
void	setReverseDirection(boolean reverse) Set the Counter to return reversed sensing on the direction.
void	setSamplesPerAverage(int samples) Set the Samples to Average which specifies the number of samples of the timer to average when calculating the period.
void	setSemiPeriodMode(boolean highSemiPeriod) Set Semi-period mode on this counter.
void	setSource(Counter.SourceType sType, DigitalIO.DigitalChannel channel) Set the Up or Down source for the counter as a digital input channel.
void	setSource(Counter.SourceType sType, DigitalIO source) Set the source object that causes the counter to count up or down.
void	setSourceEdge(Counter.SourceType sType, boolean risingEdge, boolean fallingEdge) Set the edge sensitivity on a counting source.
void	setUpdateWhenEmpty(boolean enabled) Select whether you want to continue updating the event timer output when there are no samples captured.
void	setUpDownCounterMode() Set standard up / down counting mode on this counter.

Methods inherited from class io.github.robolib.module.sensor.CounterBase

get, getFPGAIndex

Methods inherited from class java.lang.Object

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

Field Detail

m_upSource

private DigitalIO m_upSource

m_downSource

private DigitalIO m_downSource

m_allocatedUpSource

private boolean m_allocatedUpSource

m_allocatedDownSource

private boolean m_allocatedDownSource

m_counter

private java.nio.ByteBuffer m_counter

m_index

private int m_index

m_pidSType

private PIDSource.PIDSourceType m_pidSType

m_distancePerPulse

private double m_distancePerPulse

Constructor Detail

Counter

public Counter()

Create an instance of a counter where no sources are selected. Then they all must be selected by calling functions to specify the upsource and the downsource independently. The counter will start counting immediately.

Counter

public Counter(DigitalIO.DigitalChannel upChannel)

Create an instance of a Counter object. Create an up-Counter instance given a channel. The counter will start counting immediately.

Parameters:

upChannel - the DIO channel to use as the up source.

Counter

public Counter(DigitalIO upSource)

Create an instance of a counter from a Digital Input. This is used if an existing digital input is to be shared by multiple other objects such as encoders or if the Digital Source is not a DIO channel (such as an Analog Trigger) The counter will start counting immediately.

Parameters:

upSource - the digital source to count

Counter

public Counter(CounterBase.EncodingType eType,
               DigitalIO.DigitalChannel upChannel,
               DigitalIO.DigitalChannel downChannel,
               boolean inverted)

Counter

public Counter(CounterBase.EncodingType eType,
               DigitalIO upSource,
               DigitalIO downSource,
               boolean inverted)

Create an instance of a Counter object. Create an instance of a simple up-Counter. The counter will start counting immediately.

Parameters:

eType - which edges to count

upSource - first source to count

downSource - second source for direction

inverted - true to invert the count

Method Detail

free

public void free()

setSource

public void setSource(Counter.SourceType sType,
                      DigitalIO.DigitalChannel channel)

Set the Up or Down source for the counter as a digital input channel.

Parameters:

sType - the Source type Up or Down.

channel - the DIO channel to count

setSource

public void setSource(Counter.SourceType sType,
                      DigitalIO source)

Set the source object that causes the counter to count up or down. Set the up or down counting DigitalSource.

Parameters:

sType - the Source type Up or Down.

source - the digital source to count

setSourceEdge

public void setSourceEdge(Counter.SourceType sType,
                          boolean risingEdge,
                          boolean fallingEdge)

Set the edge sensitivity on a counting source. Set the source to either detect rising edges or falling edges.

Parameters:

sType - the Source type Up or Down.

risingEdge - true to count the rising edge

fallingEdge - true to count the falling edge

clearSource

public void clearSource(Counter.SourceType sType)

Disable the counting source to the counter.

Parameters:

sType - the Source type Up or Down.

setMode

private void setMode(Counter.CounterMode mode,
                     java.lang.Object... args)

setUpDownCounterMode

public void setUpDownCounterMode()

Set standard up / down counting mode on this counter. Up and down counts are sourced independently from two inputs.

setSemiPeriodMode

public void setSemiPeriodMode(boolean highSemiPeriod)

Set Semi-period mode on this counter. Counts up on both rising and falling edges.

Parameters:

highSemiPeriod - true to count up on both rising and falling

setPulseLengthMode

public void setPulseLengthMode(double threshold)

Configure the counter to count in up or down based on the length of the input pulse. This mode is most useful for direction sensitive gear tooth sensors.

Parameters:

threshold - The pulse length beyond which the counter counts the opposite direction. Units are seconds.

setExternalDirectionMode

public void setExternalDirectionMode()

Set external direction mode on this counter. Counts are sourced on the Up counter input. The Down counter input represents the direction to count.

getCount

public int getCount()

Read the current counter value. Read the value at this instant. It may still be running, so it reflects the current value. Next time it is read, it might have a different value.

Specified by:

getCount in interface CounterSource

Specified by:

getCount in class CounterBase

Returns:

the count of this counter

getDistance

public double getDistance()

Read the current scaled counter value. Read the value at this instant, scaled by the distance per pulse (defaults to 1).

Returns:

The distance since the last reset

reset

public void reset()

Reset the Counter to zero. Set the counter value to zero. This doesn't effect the running state of the counter, just sets the current value to zero.

Specified by:

reset in interface CounterSource

Specified by:

reset in class CounterBase

setMaxPeriod

public void setMaxPeriod(double maxPeriod)

Set the maximum period where the device is still considered "moving". Sets the maximum period where the device is considered moving. This value is used to determine the "stopped" state of the counter using the GetStopped method.

Specified by:

setMaxPeriod in class CounterBase

Parameters:

maxPeriod - The maximum period where the counted device is considered moving in seconds.

setUpdateWhenEmpty

public void setUpdateWhenEmpty(boolean enabled)

Select whether you want to continue updating the event timer output when there are no samples captured. The output of the event timer has a buffer of periods that are averaged and posted to a register on the FPGA. When the timer detects that the event source has stopped (based on the MaxPeriod) the buffer of samples to be averaged is emptied. If you enable the update when empty, you will be notified of the stopped source and the event time will report 0 samples. If you disable update when empty, the most recent average will remain on the output until a new sample is acquired. You will never see 0 samples output (except when there have been no events since an FPGA reset) and you will likely not see the stopped bit become true (since it is updated at the end of an average and there are no samples to average).

Parameters:

enabled - true to continue updating

getStopped

public boolean getStopped()

Determine if the clock is stopped. Determine if the clocked input is stopped based on the MaxPeriod value set using the SetMaxPeriod method. If the clock exceeds the MaxPeriod, then the device (and counter) are assumed to be stopped and it returns true.

Specified by:

getStopped in class CounterBase

Returns:

Returns true if the most recent counter period exceeds the MaxPeriod value set by SetMaxPeriod.

getDirection

public boolean getDirection()

The last direction the counter value changed.

Specified by:

getDirection in class CounterBase

Returns:

The last direction the counter value changed.

setReverseDirection

public void setReverseDirection(boolean reverse)

Set the Counter to return reversed sensing on the direction. This allows counters to change the direction they are counting in the case of 1X and 2X quadrature encoding only. Any other counter mode isn't supported.

Parameters:

reverse - true if the value counted should be negated.

getPeriod

public double getPeriod()

Get the Period of the most recent count. Returns the time interval of the most recent count. This can be used for velocity calculations to determine shaft speed.

Specified by:

getPeriod in class CounterBase

Returns:

The period of the last two pulses in units of seconds.

getRate

public double getRate()

Get the current rate of the Counter. Read the current rate of the counter accounting for the distance per pulse value. The default value for distance per pulse (1) yields units of pulses per second.

Returns:

The rate in units/sec

setSamplesPerAverage

public void setSamplesPerAverage(int samples)

Set the Samples to Average which specifies the number of samples of the timer to average when calculating the period. Perform averaging to account for mechanical imperfections or as oversampling to increase resolution.

Parameters:

samples - The number of samples to average from 1 to 127.

getSamplesPerAverage

public int getSamplesPerAverage()

Get the Samples to Average which specifies the number of samples of the timer to average when calculating the period. Perform averaging to account for mechanical imperfections or as oversampling to increase resolution.

Returns:

SamplesToAverage The number of samples being averaged (from 1 to 127)

setDistancePerPulse

public void setDistancePerPulse(double distance)

Set the distance per pulse for this counter. This sets the multiplier used to determine the distance driven based on the count value from the encoder. Set this value based on the Pulses per Revolution and factor in any gearing reductions. This distance can be in any units you like, linear or angular.

Parameters:

distance - The scale factor that will be used to convert pulses to useful units.

setPIDSourceType

public void setPIDSourceType(PIDSource.PIDSourceType sType)

Set which parameter of the encoder you are using as a process control variable. The counter class supports the rate and distance parameters.

Parameters:

sType - An enum to select the parameter.

pidGet

public double pidGet()

Specified by:

pidGet in interface PIDSource

enableModule

public void enableModule()

Enable the module

Specified by:

enableModule in interface Module

disableModule

public void disableModule()

Disable the module

Specified by:

disableModule in interface Module

getModuleEnabled

public boolean getModuleEnabled()

Specified by:

getModuleEnabled in interface Module