Class implements the PWM generation in the FPGA. More...

#include <frc/PWM.h>

Inheritance diagram for frc::PWM:

Public Types
enum	PeriodMultiplier { kPeriodMultiplier_1X = 1 , kPeriodMultiplier_2X = 2 , kPeriodMultiplier_4X = 4 }
	Represents the amount to multiply the minimum servo-pulse pwm period by. More...

Public Member Functions
	PWM (int channel, bool registerSendable=true)
	Allocate a PWM given a channel number. More...

	~PWM () override
	Free the PWM channel. More...

	PWM (PWM &&)=default

PWM &	operator= (PWM &&)=default

virtual void	SetRaw (uint16_t value)
	Set the PWM value directly to the hardware. More...

virtual uint16_t	GetRaw () const
	Get the PWM value directly from the hardware. More...

virtual void	SetPosition (double pos)
	Set the PWM value based on a position. More...

virtual double	GetPosition () const
	Get the PWM value in terms of a position. More...

virtual void	SetSpeed (double speed)
	Set the PWM value based on a speed. More...

virtual double	GetSpeed () const
	Get the PWM value in terms of speed. More...

virtual void	SetDisabled ()
	Temporarily disables the PWM output. More...

void	SetPeriodMultiplier (PeriodMultiplier mult)
	Slow down the PWM signal for old devices. More...

void	SetZeroLatch ()

void	EnableDeadbandElimination (bool eliminateDeadband)
	Optionally eliminate the deadband from a motor controller. More...

void	SetBounds (double max, double deadbandMax, double center, double deadbandMin, double min)
	Set the bounds on the PWM pulse widths. More...

void	SetRawBounds (int max, int deadbandMax, int center, int deadbandMin, int min)
	Set the bounds on the PWM values. More...

void	GetRawBounds (int32_t max, int32_t deadbandMax, int32_t center, int32_t deadbandMin, int32_t *min)
	Get the bounds on the PWM values. More...

int	GetChannel () const

Public Member Functions inherited from wpi::Sendable
virtual	~Sendable ()=default

virtual void	InitSendable (SendableBuilder &builder)=0
	Initializes this Sendable object. More...

Public Member Functions inherited from wpi::SendableHelper< PWM >
	SendableHelper (const SendableHelper &rhs)=default

	SendableHelper (SendableHelper &&rhs)

SendableHelper &	operator= (const SendableHelper &rhs)=default

SendableHelper &	operator= (SendableHelper &&rhs)

Protected Member Functions
void	InitSendable (wpi::SendableBuilder &builder) override
	Initializes this Sendable object. More...

Protected Member Functions inherited from wpi::SendableHelper< PWM >
	SendableHelper ()=default

	~SendableHelper ()

Friends
class	AddressableLED

class	DMA

Detailed Description

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 0.5ms)
0 = disabled (i.e. PWM output is held low)

Member Enumeration Documentation

◆ PeriodMultiplier

enum frc::PWM::PeriodMultiplier

Represents the amount to multiply the minimum servo-pulse pwm period by.

Enumerator

kPeriodMultiplier_1X

Don't skip pulses.

PWM pulses occur every 5.005 ms

kPeriodMultiplier_2X

Skip every other pulse.

PWM pulses occur every 10.010 ms

kPeriodMultiplier_4X

Skip three out of four pulses.

PWM pulses occur every 20.020 ms

Constructor & Destructor Documentation

◆ PWM() [1/2]

frc::PWM::PWM	(	int	channel,
		bool	registerSendable = `true`
	)

explicit

Allocate a PWM given a channel number.

Checks channel value range and allocates the appropriate channel. The allocation is only done to help users ensure that they don't double assign channels.

Parameters

channel	The PWM channel number. 0-9 are on-board, 10-19 are on the MXP port
registerSendable	If true, adds this instance to SendableRegistry and LiveWindow

◆ ~PWM()

frc::PWM::~PWM ( )

override

Free the PWM channel.

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

◆ PWM() [2/2]

frc::PWM::PWM ( PWM && )

default

Member Function Documentation

◆ EnableDeadbandElimination()

void frc::PWM::EnableDeadbandElimination ( bool eliminateDeadband )

Optionally eliminate the deadband from a motor controller.

Parameters

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

◆ GetChannel()

int frc::PWM::GetChannel ( ) const

◆ GetPosition()

virtual double frc::PWM::GetPosition ( ) const

virtual

Get the PWM value in terms of a position.

This is intended to be used by servos.

Precondition: SetMaxPositivePwm() called.; SetMinNegativePwm() called.

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

◆ GetRaw()

virtual uint16_t frc::PWM::GetRaw ( ) const

virtual

Get the PWM value directly from the hardware.

Read a raw value from a PWM channel.

Returns: Raw PWM control value.

◆ GetRawBounds()

void frc::PWM::GetRawBounds	(	int32_t *	max,
		int32_t *	deadbandMax,
		int32_t *	center,
		int32_t *	deadbandMin,
		int32_t *	min
	)

Get the bounds on the PWM values.

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

Parameters

max	The Minimum pwm value
deadbandMax	The high end of the deadband range
center	The center speed (off)
deadbandMin	The low end of the deadband range
min	The minimum pwm value

◆ GetSpeed()

virtual double frc::PWM::GetSpeed ( ) const

virtual

Get the PWM value in terms of speed.

This is intended to be used by motor controllers.

Precondition: SetMaxPositivePwm() called.; SetMinPositivePwm() called.; SetMaxNegativePwm() called.; SetMinNegativePwm() called.

Returns: The most recently set speed between -1.0 and 1.0.

◆ InitSendable()

void frc::PWM::InitSendable ( wpi::SendableBuilder & builder )

overrideprotectedvirtual

Initializes this Sendable object.

Parameters

builder sendable builder

Implements wpi::Sendable.

Reimplemented in frc::Servo.

◆ operator=()

PWM & frc::PWM::operator= ( PWM && )

default

◆ SetBounds()

void frc::PWM::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

◆ SetDisabled()

virtual void frc::PWM::SetDisabled ( )

virtual

Temporarily disables the PWM output.

The next set call will re-enable the output.

◆ SetPeriodMultiplier()

void frc::PWM::SetPeriodMultiplier ( PeriodMultiplier mult )

Slow down the PWM signal for old devices.

Parameters

mult	The period multiplier to apply to this channel

◆ SetPosition()

virtual void frc::PWM::SetPosition ( double pos )

virtual

Set the PWM value based on a position.

This is intended to be used by servos.

Precondition: SetMaxPositivePwm() called.; SetMinNegativePwm() called.

Parameters

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

◆ SetRaw()

virtual void frc::PWM::SetRaw ( uint16_t value )

virtual

Set the PWM value directly to the hardware.

Write a raw value to a PWM channel.

Parameters

value Raw PWM value.

◆ SetRawBounds()

void frc::PWM::SetRawBounds	(	int	max,
		int	deadbandMax,
		int	center,
		int	deadbandMin,
		int	min
	)

Set the bounds on the PWM values.

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

Parameters

max	The Minimum pwm value
deadbandMax	The high end of the deadband range
center	The center speed (off)
deadbandMin	The low end of the deadband range
min	The minimum pwm value

◆ SetSpeed()

virtual void frc::PWM::SetSpeed ( double speed )

virtual

Set the PWM value based on a speed.

This is intended to be used by motor controllers.

Precondition: SetMaxPositivePwm() called.; SetMinPositivePwm() called.; SetCenterPwm() called.; SetMaxNegativePwm() called.; SetMinNegativePwm() called.

Parameters

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

◆ SetZeroLatch()

void frc::PWM::SetZeroLatch ( )

Friends And Related Function Documentation

◆ AddressableLED

friend class AddressableLED

friend

◆ DMA

friend class DMA

friend

The documentation for this class was generated from the following file:

frc/PWM.h

Public Types

Public Member Functions

Protected Member Functions

Friends

Detailed Description

Member Enumeration Documentation

◆ PeriodMultiplier

Constructor & Destructor Documentation

◆ PWM() [1/2]

◆ ~PWM()

◆ PWM() [2/2]

Member Function Documentation

◆ EnableDeadbandElimination()

◆ GetChannel()

◆ GetPosition()

◆ GetRaw()

◆ GetRawBounds()

◆ GetSpeed()

◆ InitSendable()

◆ operator=()

◆ SetBounds()

◆ SetDisabled()

◆ SetPeriodMultiplier()

◆ SetPosition()

◆ SetRaw()

◆ SetRawBounds()

◆ SetSpeed()

◆ SetZeroLatch()

Friends And Related Function Documentation

◆ AddressableLED

◆ DMA