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frc::PWM Class Reference

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

#include <PWM.h>

Inheritance diagram for frc::PWM:
frc::SensorBase ITableListener frc::LiveWindowSendable frc::ErrorBase frc::Sendable frc::SafePWM frc::PWMSpeedController frc::Servo frc::Jaguar frc::SD540 frc::Spark frc::Talon frc::TalonSRX frc::Victor frc::VictorSP

Public Types

enum  PeriodMultiplier { kPeriodMultiplier_1X = 1, kPeriodMultiplier_2X = 2, kPeriodMultiplier_4X = 4 }
 

Public Member Functions

 PWM (int channel)
 Allocate a PWM given a channel number. More...
 
virtual ~PWM ()
 Free the PWM channel. More...
 
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::SensorBase
 SensorBase (const SensorBase &)=delete
 
SensorBaseoperator= (const SensorBase &)=delete
 
- Public Member Functions inherited from frc::ErrorBase
 ErrorBase (const ErrorBase &)=delete
 
ErrorBaseoperator= (const ErrorBase &)=delete
 
virtual ErrorGetError ()
 Retrieve the current error. More...
 
virtual const ErrorGetError () const
 
virtual void SetErrnoError (llvm::StringRef contextMessage, llvm::StringRef filename, llvm::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, llvm::StringRef contextMessage, llvm::StringRef filename, llvm::StringRef function, int lineNumber) const
 Set the current error information associated from the nivision Imaq API. More...
 
virtual void SetError (Error::Code code, llvm::StringRef contextMessage, llvm::StringRef filename, llvm::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, llvm::StringRef contextMessage, llvm::StringRef filename, llvm::StringRef function, int lineNumber) const
 Set the current error information associated with this sensor. More...
 
virtual void SetWPIError (llvm::StringRef errorMessage, Error::Code code, llvm::StringRef contextMessage, llvm::StringRef filename, llvm::StringRef function, int lineNumber) const
 Set the current error information associated with this sensor. More...
 
virtual void CloneError (const ErrorBase &rhs) const
 
virtual void ClearError () const
 Clear the current error information associated with this sensor.
 
virtual bool StatusIsFatal () const
 Check if the current error code represents a fatal error. More...
 
- Public Member Functions inherited from ITableListener
virtual void ValueChangedEx (ITable *source, llvm::StringRef key, std::shared_ptr< nt::Value > value, unsigned int flags)
 Extended version of ValueChanged. More...
 

Protected Member Functions

void ValueChanged (ITable *source, llvm::StringRef key, std::shared_ptr< nt::Value > value, bool isNew) override
 Called when a key-value pair is changed in a ITable. More...
 
void UpdateTable () override
 Update the table for this sendable object with the latest values.
 
void StartLiveWindowMode () override
 Start having this sendable object automatically respond to value changes reflect the value on the table.
 
void StopLiveWindowMode () override
 Stop having this sendable object automatically respond to value changes.
 
std::string GetSmartDashboardType () const override
 
void InitTable (std::shared_ptr< ITable > subTable) override
 Initializes a table for this sendable object. More...
 
std::shared_ptr< ITableGetTable () const override
 

Protected Attributes

std::shared_ptr< ITablem_table
 
- Protected Attributes inherited from frc::ErrorBase
Error m_error
 

Additional Inherited Members

- Static Public Member Functions inherited from frc::SensorBase
static int GetDefaultSolenoidModule ()
 
static bool CheckSolenoidModule (int moduleNumber)
 Check that the solenoid module number is valid. More...
 
static bool CheckDigitalChannel (int channel)
 Check that the digital channel number is valid. More...
 
static bool CheckRelayChannel (int channel)
 Check that the relay channel number is valid. More...
 
static bool CheckPWMChannel (int channel)
 Check that the digital channel number is valid. More...
 
static bool CheckAnalogInputChannel (int channel)
 Check that the analog input number is value. More...
 
static bool CheckAnalogOutputChannel (int channel)
 Check that the analog output number is valid. More...
 
static bool CheckSolenoidChannel (int channel)
 Verify that the solenoid channel number is within limits. More...
 
static bool CheckPDPChannel (int channel)
 Verify that the power distribution channel number is within limits. More...
 
- Static Public Member Functions inherited from frc::ErrorBase
static void SetGlobalError (Error::Code code, llvm::StringRef contextMessage, llvm::StringRef filename, llvm::StringRef function, int lineNumber)
 
static void SetGlobalWPIError (llvm::StringRef errorMessage, llvm::StringRef contextMessage, llvm::StringRef filename, llvm::StringRef function, int lineNumber)
 
static ErrorGetGlobalError ()
 Retrieve the current global error.
 
- Static Public Attributes inherited from frc::SensorBase
static const int kDigitalChannels = HAL_GetNumDigitalChannels()
 
static const int kAnalogInputs = HAL_GetNumAnalogInputs()
 
static const int kAnalogOutputs
 
static const int kSolenoidChannels = HAL_GetNumSolenoidChannels()
 
static const int kSolenoidModules = HAL_GetNumPCMModules()
 
static const int kPwmChannels = HAL_GetNumPWMChannels()
 
static const int kRelayChannels = HAL_GetNumRelayHeaders()
 
static const int kPDPChannels = HAL_GetNumPDPChannels()
 
- Static Protected Attributes inherited from frc::ErrorBase
static hal::priority_mutex _globalErrorMutex
 
static Error _globalError
 

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. 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)

Constructor & Destructor Documentation

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
PWM::~PWM ( )
virtual

Free the PWM channel.

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

Member Function Documentation

void 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.
double 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.
uint16_t 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 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
std::string PWM::GetSmartDashboardType ( ) const
overrideprotectedvirtual
Returns
the string representation of the named data type that will be used by the smart dashboard for this sendable

Implements frc::Sendable.

double 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.
std::shared_ptr< ITable > PWM::GetTable ( ) const
overrideprotectedvirtual
Returns
the table that is currently associated with the sendable

Implements frc::Sendable.

void PWM::InitTable ( std::shared_ptr< ITable subtable)
overrideprotectedvirtual

Initializes a table for this sendable object.

Parameters
subtableThe table to put the values in.

Implements frc::Sendable.

void 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
void PWM::SetDisabled ( )
virtual

Temporarily disables the PWM output.

The next set call will reenable the output.

void PWM::SetPeriodMultiplier ( PeriodMultiplier  mult)

Slow down the PWM signal for old devices.

Parameters
multThe period multiplier to apply to this channel
void 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.
void 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 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
void 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.

Reimplemented in frc::SafePWM.

void PWM::ValueChanged ( ITable source,
llvm::StringRef  key,
std::shared_ptr< nt::Value value,
bool  isNew 
)
overrideprotectedvirtual

Called when a key-value pair is changed in a ITable.

Parameters
sourcethe table the key-value pair exists in
keythe key associated with the value that changed
valuethe new value
isNewtrue if the key did not previously exist in the table, otherwise it is false

Implements ITableListener.


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