WPILibC++ 2024.3.2
frc::PWM Class Reference

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

#include <frc/PWM.h>

Inheritance diagram for frc::PWM:
wpi::Sendable wpi::SendableHelper< PWM > frc::Servo

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
 
PWMoperator= (PWM &&)=default
 
virtual void SetPulseTime (units::microsecond_t time)
 Set the PWM pulse time directly to the hardware. More...
 
virtual units::microsecond_t GetPulseTime () const
 Get the PWM pulse time 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 ()
 Latches PWM to zero. More...
 
void EnableDeadbandElimination (bool eliminateDeadband)
 Optionally eliminate the deadband from a motor controller. More...
 
void SetBounds (units::microsecond_t max, units::microsecond_t deadbandMax, units::microsecond_t center, units::microsecond_t deadbandMin, units::microsecond_t min)
 Set the bounds on the PWM pulse widths. More...
 
void GetBounds (units::microsecond_t *max, units::microsecond_t *deadbandMax, units::microsecond_t *center, units::microsecond_t *deadbandMin, units::microsecond_t *min)
 Get the bounds on the PWM values. More...
 
void SetAlwaysHighMode ()
 Sets the PWM output to be a continuous high signal while enabled. 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)
 
SendableHelperoperator= (const SendableHelper &rhs)=default
 
SendableHelperoperator= (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 microseconds to keep the pulse high, with a range of 0 (off) to 4096. Changes are immediately sent to the FPGA, and the update occurs at the next FPGA cycle (5.05ms). There is no delay.

Member Enumeration Documentation

◆ PeriodMultiplier

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

Enumerator
kPeriodMultiplier_1X 

Don't skip pulses.

PWM pulses occur every 5.05 ms

kPeriodMultiplier_2X 

Skip every other pulse.

PWM pulses occur every 10.10 ms

kPeriodMultiplier_4X 

Skip three out of four pulses.

PWM pulses occur every 20.20 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
channelThe PWM channel number. 0-9 are on-board, 10-19 are on the MXP port
registerSendableIf 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
eliminateDeadbandIf 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.

◆ GetBounds()

void frc::PWM::GetBounds ( units::microsecond_t *  max,
units::microsecond_t *  deadbandMax,
units::microsecond_t *  center,
units::microsecond_t *  deadbandMin,
units::microsecond_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
maxThe maximum pwm value
deadbandMaxThe high end of the deadband range
centerThe center speed (off)
deadbandMinThe low end of the deadband range
minThe minimum pwm value

◆ 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
SetBounds() called.
Returns
The position the servo is set to between 0.0 and 1.0.

◆ GetPulseTime()

virtual units::microsecond_t frc::PWM::GetPulseTime ( ) const
virtual

Get the PWM pulse time directly from the hardware.

Read a microsecond value from a PWM channel.

Returns
Microsecond PWM control 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
SetBounds() 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
buildersendable builder

Implements wpi::Sendable.

Reimplemented in frc::Servo.

◆ operator=()

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

◆ SetAlwaysHighMode()

void frc::PWM::SetAlwaysHighMode ( )

Sets the PWM output to be a continuous high signal while enabled.

◆ SetBounds()

void frc::PWM::SetBounds ( units::microsecond_t  max,
units::microsecond_t  deadbandMax,
units::microsecond_t  center,
units::microsecond_t  deadbandMin,
units::microsecond_t  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
maxThe max PWM pulse width in us
deadbandMaxThe high end of the deadband range pulse width in us
centerThe center (off) pulse width in us
deadbandMinThe low end of the deadband pulse width in us
minThe minimum pulse width in us

◆ 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
multThe 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
SetBounds() called.
Parameters
posThe position to set the servo between 0.0 and 1.0.

◆ SetPulseTime()

virtual void frc::PWM::SetPulseTime ( units::microsecond_t  time)
virtual

Set the PWM pulse time directly to the hardware.

Write a microsecond value to a PWM channel.

Parameters
timeMicrosecond 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
SetBounds() called.
Parameters
speedThe speed to set the motor controller between -1.0 and 1.0.

◆ SetZeroLatch()

void frc::PWM::SetZeroLatch ( )

Latches PWM to zero.

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: