edu.wpi.first.wpilibj

Class PWM

java.lang.Object

edu.wpi.first.wpilibj.SendableBase

edu.wpi.first.wpilibj.PWM

All Implemented Interfaces:

Sendable

Direct Known Subclasses:

SafePWM, Servo

public class PWM
extends SendableBase
implements Sendable

Class implements the PWM generation in the FPGA.

The values supplied as arguments for PWM outputs range from -1.0 to 1.0. They are mapped to the hardware dependent values, in this case 0-2000 for the FPGA. Changes are immediately sent to the FPGA, and the update occurs at the next FPGA cycle (5.005ms). There is no delay.

As of revision 0.1.10 of the FPGA, the FPGA interprets the 0-2000 values as follows: - 2000 = maximum pulse width - 1999 to 1001 = linear scaling from "full forward" to "center" - 1000 = center value - 999 to 2 = linear scaling from "center" to "full reverse" - 1 = minimum pulse width (currently .5ms) - 0 = disabled (i.e. PWM output is held low)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PWM.PeriodMultiplier Represents the amount to multiply the minimum servo-pulse pwm period by.

Constructor Summary

Constructors

Constructor and Description
PWM(int channel) Allocate a PWM given a channel.

Method Summary

Modifier and Type	Method and Description
void	enableDeadbandElimination(boolean eliminateDeadband) Optionally eliminate the deadband from a speed controller.
void	free() Free the PWM channel.
int	getChannel() Gets the channel number associated with the PWM Object.
double	getPosition() Get the PWM value in terms of a position.
int	getRaw() Get the PWM value directly from the hardware.
PWMConfigDataResult	getRawBounds() Gets the bounds on the PWM pulse widths.
double	getSpeed() Get the PWM value in terms of speed.
void	initSendable(SendableBuilder builder) Initializes this Sendable object.
void	setBounds(double max, double deadbandMax, double center, double deadbandMin, double min) Set the bounds on the PWM pulse widths.
void	setDisabled() Temporarily disables the PWM output.
void	setPeriodMultiplier(PWM.PeriodMultiplier mult) Slow down the PWM signal for old devices.
void	setPosition(double pos) Set the PWM value based on a position.
void	setRaw(int value) Set the PWM value directly to the hardware.
void	setSpeed(double speed) Set the PWM value based on a speed.
protected void	setZeroLatch()

Methods inherited from class edu.wpi.first.wpilibj.SendableBase

addChild, getName, getSubsystem, setName, setName, setName, setSubsystem

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.wpi.first.wpilibj.Sendable

getName, getSubsystem, setName, setName, setSubsystem

Constructor Detail

PWM

public PWM(int channel)

Allocate a PWM given a channel.

Parameters:

channel - The PWM channel number. 0-9 are on-board, 10-19 are on the MXP port

Method Detail

free

public void free()

Free the PWM channel.

Free the resource associated with the PWM channel and set the value to 0.

Overrides:

free in class SendableBase

enableDeadbandElimination

public void enableDeadbandElimination(boolean eliminateDeadband)

Optionally eliminate the deadband from a speed controller.

Parameters:

eliminateDeadband - If true, set the motor curve on the Jaguar to eliminate the deadband in the middle of the range. Otherwise, keep the full range without modifying any values.

setBounds

public void setBounds(double max,
                      double deadbandMax,
                      double center,
                      double deadbandMin,
                      double min)

Set the bounds on the PWM pulse widths. This sets the bounds on the PWM values for a particular type of controller. The values determine the upper and lower speeds as well as the deadband bracket.

Parameters:

max - The max PWM pulse width in ms

deadbandMax - The high end of the deadband range pulse width in ms

center - The center (off) pulse width in ms

deadbandMin - The low end of the deadband pulse width in ms

min - The minimum pulse width in ms

getRawBounds

public PWMConfigDataResult getRawBounds()

Gets the bounds on the PWM pulse widths. This Gets the bounds on the PWM values for a particular type of controller. The values determine the upper and lower speeds as well as the deadband bracket.

getChannel

public int getChannel()

Gets the channel number associated with the PWM Object.

Returns:

The channel number.

setPosition

public void setPosition(double pos)

Set the PWM value based on a position.

This is intended to be used by servos.

Parameters:

pos - The position to set the servo between 0.0 and 1.0.

getPosition

public double getPosition()

Get the PWM value in terms of a position.

This is intended to be used by servos.

Returns:

The position the servo is set to between 0.0 and 1.0.

setSpeed

public void setSpeed(double speed)

Set the PWM value based on a speed.

This is intended to be used by speed controllers.

Parameters:

speed - The speed to set the speed controller between -1.0 and 1.0.

getSpeed

public double getSpeed()

Get the PWM value in terms of speed.

This is intended to be used by speed controllers.

Returns:

The most recently set speed between -1.0 and 1.0.

setRaw

public void setRaw(int value)

Set the PWM value directly to the hardware.

Write a raw value to a PWM channel.

Parameters:

value - Raw PWM value. Range 0 - 255.

getRaw

public int getRaw()

Get the PWM value directly from the hardware.

Read a raw value from a PWM channel.

Returns:

Raw PWM control value. Range: 0 - 255.

setDisabled

public void setDisabled()

Temporarily disables the PWM output. The next set call will reenable the output.

setPeriodMultiplier

public void setPeriodMultiplier(PWM.PeriodMultiplier mult)

Slow down the PWM signal for old devices.

Parameters:

mult - The period multiplier to apply to this channel

setZeroLatch

protected void setZeroLatch()

initSendable

public void initSendable(SendableBuilder builder)

Description copied from interface: Sendable

Initializes this Sendable object.

Specified by:

initSendable in interface Sendable

Parameters:

builder - sendable builder