Analog input class. More...

#include <frc/AnalogInput.h>

Inheritance diagram for frc::AnalogInput:

Public Member Functions
	AnalogInput (int channel)
	Construct an analog input. More...

	~AnalogInput () override

	AnalogInput (AnalogInput &&)=default

AnalogInput &	operator= (AnalogInput &&)=default

int	GetValue () const
	Get a sample straight from this channel. More...

int	GetAverageValue () const
	Get a sample from the output of the oversample and average engine for this channel. More...

double	GetVoltage () const
	Get a scaled sample straight from this channel. More...

double	GetAverageVoltage () const
	Get a scaled sample from the output of the oversample and average engine for this channel. More...

int	GetChannel () const
	Get the channel number. More...

void	SetAverageBits (int bits)
	Set the number of averaging bits. More...

int	GetAverageBits () const
	Get the number of averaging bits previously configured. More...

void	SetOversampleBits (int bits)
	Set the number of oversample bits. More...

int	GetOversampleBits () const
	Get the number of oversample bits previously configured. More...

int	GetLSBWeight () const
	Get the factory scaling least significant bit weight constant. More...

int	GetOffset () const
	Get the factory scaling offset constant. More...

bool	IsAccumulatorChannel () const
	Is the channel attached to an accumulator. More...

void	InitAccumulator ()
	Initialize the accumulator. More...

void	SetAccumulatorInitialValue (int64_t value)
	Set an initial value for the accumulator. More...

void	ResetAccumulator ()
	Resets the accumulator to the initial value. More...

void	SetAccumulatorCenter (int center)
	Set the center value of the accumulator. More...

void	SetAccumulatorDeadband (int deadband)
	Set the accumulator's deadband. More...

int64_t	GetAccumulatorValue () const
	Read the accumulated value. More...

int64_t	GetAccumulatorCount () const
	Read the number of accumulated values. More...

void	GetAccumulatorOutput (int64_t &value, int64_t &count) const
	Read the accumulated value and the number of accumulated values atomically. More...

void	SetSimDevice (HAL_SimDeviceHandle device)
	Indicates this input is used by a simulated device. More...

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

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< AnalogInput >
	SendableHelper (const SendableHelper &rhs)=default

	SendableHelper (SendableHelper &&rhs)

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

SendableHelper &	operator= (SendableHelper &&rhs)

Static Public Member Functions
static void	SetSampleRate (double samplesPerSecond)
	Set the sample rate per channel for all analog channels. More...

static double	GetSampleRate ()
	Get the current sample rate for all channels. More...

Static Public Attributes
static constexpr int	kAccumulatorModuleNumber = 1

static constexpr int	kAccumulatorNumChannels = 2

static constexpr int	kAccumulatorChannels [kAccumulatorNumChannels] = {0, 1}

Friends
class	AnalogTrigger

class	AnalogGyro

class	DMA

class	DMASample

Additional Inherited Members
Protected Member Functions inherited from wpi::SendableHelper< AnalogInput >
	SendableHelper ()=default

	~SendableHelper ()

Detailed Description

Analog input class.

Connected to each analog channel is an averaging and oversampling engine. This engine accumulates the specified ( by SetAverageBits() and SetOversampleBits() ) number of samples before returning a new value. This is not a sliding window average. The only difference between the oversampled samples and the averaged samples is that the oversampled samples are simply accumulated effectively increasing the resolution, while the averaged samples are divided by the number of samples to retain the resolution, but get more stable values.

Constructor & Destructor Documentation

◆ AnalogInput() [1/2]

frc::AnalogInput::AnalogInput ( int channel )

explicit

Construct an analog input.

Parameters

channel The channel number on the roboRIO to represent. 0-3 are on-board 4-7 are on the MXP port.

◆ ~AnalogInput()

frc::AnalogInput::~AnalogInput ( )

override

◆ AnalogInput() [2/2]

frc::AnalogInput::AnalogInput ( AnalogInput && )

default

Member Function Documentation

◆ GetAccumulatorCount()

int64_t frc::AnalogInput::GetAccumulatorCount ( ) const

Read the number of accumulated values.

Read the count of the accumulated values since the accumulator was last Reset().

Returns: The number of times samples from the channel were accumulated.

◆ GetAccumulatorOutput()

void frc::AnalogInput::GetAccumulatorOutput	(	int64_t &	value,
		int64_t &	count
	)		const

Read the accumulated value and the number of accumulated values atomically.

This function reads the value and count from the FPGA atomically. This can be used for averaging.

Parameters

value	Reference to the 64-bit accumulated output.
count	Reference to the number of accumulation cycles.

◆ GetAccumulatorValue()

int64_t frc::AnalogInput::GetAccumulatorValue ( ) const

Read the accumulated value.

Read the value that has been accumulating. The accumulator is attached after the oversample and average engine.

Returns: The 64-bit value accumulated since the last Reset().

◆ GetAverageBits()

int frc::AnalogInput::GetAverageBits ( ) const

Get the number of averaging bits previously configured.

This gets the number of averaging bits from the FPGA. The actual number of averaged samples is 2^bits. The averaging is done automatically in the FPGA.

Returns: Number of bits of averaging previously configured.

◆ GetAverageValue()

int frc::AnalogInput::GetAverageValue ( ) const

Get a sample from the output of the oversample and average engine for this channel.

The sample is 12-bit + the bits configured in SetOversampleBits(). The value configured in SetAverageBits() will cause this value to be averaged 2**bits number of samples.

This is not a sliding window. The sample will not change until 2**(OversampleBits + AverageBits) samples have been acquired from the module on this channel.

Use GetAverageVoltage() to get the analog value in calibrated units.

Returns: A sample from the oversample and average engine for this channel.

◆ GetAverageVoltage()

double frc::AnalogInput::GetAverageVoltage ( ) const

Get a scaled sample from the output of the oversample and average engine for this channel.

The value is scaled to units of Volts using the calibrated scaling data from GetLSBWeight() and GetOffset().

Using oversampling will cause this value to be higher resolution, but it will update more slowly.

Using averaging will cause this value to be more stable, but it will update more slowly.

Returns: A scaled sample from the output of the oversample and average engine for this channel.

◆ GetChannel()

int frc::AnalogInput::GetChannel ( ) const

Get the channel number.

Returns: The channel number.

◆ GetLSBWeight()

int frc::AnalogInput::GetLSBWeight ( ) const

Get the factory scaling least significant bit weight constant.

Volts = ((LSB_Weight * 1e-9) * raw) - (Offset * 1e-9)

Returns: Least significant bit weight.

◆ GetOffset()

int frc::AnalogInput::GetOffset ( ) const

Get the factory scaling offset constant.

Volts = ((LSB_Weight * 1e-9) * raw) - (Offset * 1e-9)

Returns: Offset constant.

◆ GetOversampleBits()

int frc::AnalogInput::GetOversampleBits ( ) const

Get the number of oversample bits previously configured.

This gets the number of oversample bits from the FPGA. The actual number of oversampled values is 2^bits. The oversampling is done automatically in the FPGA.

Returns: Number of bits of oversampling previously configured.

◆ GetSampleRate()

static double frc::AnalogInput::GetSampleRate ( )

static

Get the current sample rate for all channels.

Returns: Sample rate.

◆ GetValue()

int frc::AnalogInput::GetValue ( ) const

Get a sample straight from this channel.

The sample is a 12-bit value representing the 0V to 5V range of the A/D converter in the module. The units are in A/D converter codes. Use GetVoltage() to get the analog value in calibrated units.

Returns: A sample straight from this channel.

◆ GetVoltage()

double frc::AnalogInput::GetVoltage ( ) const

Get a scaled sample straight from this channel.

The value is scaled to units of Volts using the calibrated scaling data from GetLSBWeight() and GetOffset().

Returns: A scaled sample straight from this channel.

◆ InitAccumulator()

void frc::AnalogInput::InitAccumulator ( )

Initialize the accumulator.

◆ InitSendable()

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

overridevirtual

Initializes this Sendable object.

Parameters

builder sendable builder

Implements wpi::Sendable.

◆ IsAccumulatorChannel()

bool frc::AnalogInput::IsAccumulatorChannel ( ) const

Is the channel attached to an accumulator.

Returns: The analog input is attached to an accumulator.

◆ operator=()

AnalogInput & frc::AnalogInput::operator= ( AnalogInput && )

default

◆ ResetAccumulator()

void frc::AnalogInput::ResetAccumulator ( )

Resets the accumulator to the initial value.

◆ SetAccumulatorCenter()

void frc::AnalogInput::SetAccumulatorCenter ( int center )

Set the center value of the accumulator.

The center value is subtracted from each A/D value before it is added to the accumulator. This is used for the center value of devices like gyros and accelerometers to take the device offset into account when integrating.

This center value is based on the output of the oversampled and averaged source from the accumulator channel. Because of this, any non-zero oversample bits will affect the size of the value for this field.

◆ SetAccumulatorDeadband()

void frc::AnalogInput::SetAccumulatorDeadband ( int deadband )

Set the accumulator's deadband.

◆ SetAccumulatorInitialValue()

void frc::AnalogInput::SetAccumulatorInitialValue ( int64_t value )

Set an initial value for the accumulator.

This will be added to all values returned to the user.

Parameters

value The value that the accumulator should start from when reset.

◆ SetAverageBits()

void frc::AnalogInput::SetAverageBits ( int bits )

Set the number of averaging bits.

This sets the number of averaging bits. The actual number of averaged samples is 2^bits.

Use averaging to improve the stability of your measurement at the expense of sampling rate. The averaging is done automatically in the FPGA.

Parameters

bits	Number of bits of averaging.

◆ SetOversampleBits()

void frc::AnalogInput::SetOversampleBits ( int bits )

Set the number of oversample bits.

This sets the number of oversample bits. The actual number of oversampled values is 2^bits. Use oversampling to improve the resolution of your measurements at the expense of sampling rate. The oversampling is done automatically in the FPGA.

Parameters

bits	Number of bits of oversampling.

◆ SetSampleRate()

static void frc::AnalogInput::SetSampleRate ( double samplesPerSecond )

static

Set the sample rate per channel for all analog channels.

The maximum rate is 500kS/s divided by the number of channels in use. This is 62500 samples/s per channel.

Parameters

samplesPerSecond The number of samples per second.

◆ SetSimDevice()

void frc::AnalogInput::SetSimDevice ( HAL_SimDeviceHandle device )

Indicates this input is used by a simulated device.

Parameters

device simulated device handle

Friends And Related Function Documentation

◆ AnalogGyro

friend class AnalogGyro

friend

◆ AnalogTrigger

friend class AnalogTrigger

friend

◆ DMA

friend class DMA

friend

◆ DMASample

friend class DMASample

friend

Member Data Documentation

◆ kAccumulatorChannels

constexpr int frc::AnalogInput::kAccumulatorChannels[kAccumulatorNumChannels] = {0, 1}

staticconstexpr

◆ kAccumulatorModuleNumber

constexpr int frc::AnalogInput::kAccumulatorModuleNumber = 1

staticconstexpr

◆ kAccumulatorNumChannels

constexpr int frc::AnalogInput::kAccumulatorNumChannels = 2

staticconstexpr

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

frc/AnalogInput.h

Public Member Functions

Static Public Member Functions

Static Public Attributes

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ AnalogInput() [1/2]

◆ ~AnalogInput()

◆ AnalogInput() [2/2]

Member Function Documentation

◆ GetAccumulatorCount()

◆ GetAccumulatorOutput()

◆ GetAccumulatorValue()

◆ GetAverageBits()

◆ GetAverageValue()

◆ GetAverageVoltage()

◆ GetChannel()

◆ GetLSBWeight()

◆ GetOffset()

◆ GetOversampleBits()

◆ GetSampleRate()

◆ GetValue()

◆ GetVoltage()

◆ InitAccumulator()

◆ InitSendable()

◆ IsAccumulatorChannel()

◆ operator=()

◆ ResetAccumulator()

◆ SetAccumulatorCenter()

◆ SetAccumulatorDeadband()

◆ SetAccumulatorInitialValue()

◆ SetAverageBits()

◆ SetOversampleBits()

◆ SetSampleRate()

◆ SetSimDevice()

Friends And Related Function Documentation

◆ AnalogGyro

◆ AnalogTrigger

◆ DMA

◆ DMASample

Member Data Documentation

◆ kAccumulatorChannels

◆ kAccumulatorModuleNumber

◆ kAccumulatorNumChannels