WPILibC++  2019.3.1
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Modules Pages
frc::PWM Class Reference

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

#include <PWM.h>

Inheritance diagram for frc::PWM:
frc::MotorSafety frc::SendableBase frc::ErrorBase frc::Sendable frc::PWMSpeedController frc::Servo frc::DMC60 frc::Jaguar frc::PWMTalonSRX frc::PWMVictorSPX frc::SD540 frc::Spark frc::Talon frc::Victor frc::VictorSP

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)
 Allocate a PWM given a channel number. More...
 
 ~PWM () override
 Free the PWM channel. More...
 
 PWM (PWM &&rhs)
 
PWMoperator= (PWM &&rhs)
 
void StopMotor () override
 
void GetDescription (wpi::raw_ostream &desc) const override
 
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 speed 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 frc::MotorSafety
 MotorSafety (MotorSafety &&rhs)
 
MotorSafetyoperator= (MotorSafety &&rhs)
 
void Feed ()
 Feed the motor safety object. More...
 
void SetExpiration (double expirationTime)
 Set the expiration time for the corresponding motor safety object. More...
 
double GetExpiration () const
 Retrieve the timeout value for the corresponding motor safety object. More...
 
bool IsAlive () const
 Determine if the motor is still operating or has timed out. More...
 
void SetSafetyEnabled (bool enabled)
 Enable/disable motor safety for this device. More...
 
bool IsSafetyEnabled () const
 Return the state of the motor safety enabled flag. More...
 
void Check ()
 Check if this motor has exceeded its timeout. More...
 
- Public Member Functions inherited from frc::ErrorBase
 ErrorBase (ErrorBase &&)=default
 
ErrorBaseoperator= (ErrorBase &&)=default
 
virtual ErrorGetError ()
 Retrieve the current error. More...
 
virtual const ErrorGetError () const
 Retrieve the current error. More...
 
virtual void ClearError () const
 Clear the current error information associated with this sensor.
 
virtual void SetErrnoError (const wpi::Twine &contextMessage, wpi::StringRef filename, wpi::StringRef function, int lineNumber) const
 Set error information associated with a C library call that set an error to the "errno" global variable. More...
 
virtual void SetImaqError (int success, const wpi::Twine &contextMessage, wpi::StringRef filename, wpi::StringRef function, int lineNumber) const
 Set the current error information associated from the nivision Imaq API. More...
 
virtual void SetError (Error::Code code, const wpi::Twine &contextMessage, wpi::StringRef filename, wpi::StringRef function, int lineNumber) const
 Set the current error information associated with this sensor. More...
 
virtual void SetErrorRange (Error::Code code, int32_t minRange, int32_t maxRange, int32_t requestedValue, const wpi::Twine &contextMessage, wpi::StringRef filename, wpi::StringRef function, int lineNumber) const
 Set the current error information associated with this sensor. More...
 
virtual void SetWPIError (const wpi::Twine &errorMessage, Error::Code code, const wpi::Twine &contextMessage, wpi::StringRef filename, wpi::StringRef function, int lineNumber) const
 Set the current error information associated with this sensor. More...
 
virtual void CloneError (const ErrorBase &rhs) const
 
virtual bool StatusIsFatal () const
 Check if the current error code represents a fatal error. More...
 
- Public Member Functions inherited from frc::SendableBase
 SendableBase (bool addLiveWindow=true)
 Creates an instance of the sensor base. More...
 
 SendableBase (SendableBase &&rhs)
 
SendableBaseoperator= (SendableBase &&rhs)
 
std::string GetName () const final
 Gets the name of this Sendable object. More...
 
void SetName (const wpi::Twine &name) final
 Sets the name of this Sendable object. More...
 
std::string GetSubsystem () const final
 Gets the subsystem name of this Sendable object. More...
 
void SetSubsystem (const wpi::Twine &subsystem) final
 Sets the subsystem name of this Sendable object. More...
 
- Public Member Functions inherited from frc::Sendable
 Sendable (Sendable &&)=default
 
Sendableoperator= (Sendable &&)=default
 
void SetName (const wpi::Twine &subsystem, const wpi::Twine &name)
 Sets both the subsystem name and device name of this Sendable object. More...
 

Protected Member Functions

void InitSendable (SendableBuilder &builder) override
 Initializes this Sendable object. More...
 
- Protected Member Functions inherited from frc::SendableBase
void AddChild (std::shared_ptr< Sendable > child)
 Add a child component. More...
 
void AddChild (void *child)
 Add a child component. More...
 
void SetName (const wpi::Twine &moduleType, int channel)
 Sets the name of the sensor with a channel number. More...
 
void SetName (const wpi::Twine &moduleType, int moduleNumber, int channel)
 Sets the name of the sensor with a module and channel number. More...
 

Additional Inherited Members

- Static Public Member Functions inherited from frc::MotorSafety
static void CheckMotors ()
 Check the motors to see if any have timed out. More...
 
- Static Public Member Functions inherited from frc::ErrorBase
static void SetGlobalError (Error::Code code, const wpi::Twine &contextMessage, wpi::StringRef filename, wpi::StringRef function, int lineNumber)
 
static void SetGlobalWPIError (const wpi::Twine &errorMessage, const wpi::Twine &contextMessage, wpi::StringRef filename, wpi::StringRef function, int lineNumber)
 
static const ErrorGetGlobalError ()
 Retrieve the current global error.
 
- Protected Attributes inherited from frc::ErrorBase
Error m_error
 

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 .5ms)
  • 0 = disabled (i.e. PWM output is held low)

Member Enumeration Documentation

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

frc::PWM::PWM ( int  channel)
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
frc::PWM::~PWM ( )
override

Free the PWM channel.

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

Member Function Documentation

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

Optionally eliminate the deadband from a speed controller.

Parameters
eliminateDeadbandIf 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.
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.
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.
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
maxThe Minimum pwm value
deadbandMaxThe high end of the deadband range
centerThe center speed (off)
deadbandMinThe low end of the deadband range
minThe minimum pwm value
virtual double frc::PWM::GetSpeed ( ) const
virtual

Get the PWM value in terms of speed.

This is intended to be used by speed controllers.

Precondition
SetMaxPositivePwm() called.
SetMinPositivePwm() called.
SetMaxNegativePwm() called.
SetMinNegativePwm() called.
Returns
The most recently set speed between -1.0 and 1.0.
void frc::PWM::InitSendable ( SendableBuilder builder)
overrideprotectedvirtual

Initializes this Sendable object.

Parameters
buildersendable builder

Implements frc::Sendable.

Reimplemented in frc::PWMSpeedController.

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
maxThe max PWM pulse width in ms
deadbandMaxThe high end of the deadband range pulse width in ms
centerThe center (off) pulse width in ms
deadbandMinThe low end of the deadband pulse width in ms
minThe minimum pulse width in ms
virtual void frc::PWM::SetDisabled ( )
virtual

Temporarily disables the PWM output.

The next set call will reenable the output.

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

Slow down the PWM signal for old devices.

Parameters
multThe period multiplier to apply to this channel
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
posThe position to set the servo between 0.0 and 1.0.
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
valueRaw PWM value.
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
maxThe Minimum pwm value
deadbandMaxThe high end of the deadband range
centerThe center speed (off)
deadbandMinThe low end of the deadband range
minThe minimum pwm value
virtual void frc::PWM::SetSpeed ( double  speed)
virtual

Set the PWM value based on a speed.

This is intended to be used by speed controllers.

Precondition
SetMaxPositivePwm() called.
SetMinPositivePwm() called.
SetCenterPwm() called.
SetMaxNegativePwm() called.
SetMinNegativePwm() called.
Parameters
speedThe speed to set the speed controller between -1.0 and 1.0.

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