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frc::SPI Class Reference

SPI bus interface class. More...

#include <SPI.h>

Inheritance diagram for frc::SPI:
frc::ErrorBase

Public Types

enum  Port {
  kOnboardCS0 = 0, kOnboardCS1, kOnboardCS2, kOnboardCS3,
  kMXP
}
 

Public Member Functions

 SPI (Port port)
 Constructor. More...
 
 SPI (SPI &&rhs)
 
SPIoperator= (SPI &&rhs)
 
void SetClockRate (double hz)
 Configure the rate of the generated clock signal. More...
 
void SetMSBFirst ()
 Configure the order that bits are sent and received on the wire to be most significant bit first.
 
void SetLSBFirst ()
 Configure the order that bits are sent and received on the wire to be least significant bit first.
 
void SetSampleDataOnLeadingEdge ()
 Configure that the data is stable on the leading edge and the data changes on the trailing edge.
 
void SetSampleDataOnTrailingEdge ()
 Configure that the data is stable on the trailing edge and the data changes on the leading edge.
 
void SetSampleDataOnFalling ()
 Configure that the data is stable on the falling edge and the data changes on the rising edge.
 
void SetSampleDataOnRising ()
 Configure that the data is stable on the rising edge and the data changes on the falling edge.
 
void SetClockActiveLow ()
 Configure the clock output line to be active low. More...
 
void SetClockActiveHigh ()
 Configure the clock output line to be active high. More...
 
void SetChipSelectActiveHigh ()
 Configure the chip select line to be active high.
 
void SetChipSelectActiveLow ()
 Configure the chip select line to be active low.
 
virtual int Write (uint8_t *data, int size)
 Write data to the slave device. More...
 
virtual int Read (bool initiate, uint8_t *dataReceived, int size)
 Read a word from the receive FIFO. More...
 
virtual int Transaction (uint8_t *dataToSend, uint8_t *dataReceived, int size)
 Perform a simultaneous read/write transaction with the device. More...
 
void InitAuto (int bufferSize)
 Initialize automatic SPI transfer engine. More...
 
void FreeAuto ()
 Frees the automatic SPI transfer engine.
 
void SetAutoTransmitData (wpi::ArrayRef< uint8_t > dataToSend, int zeroSize)
 Set the data to be transmitted by the engine. More...
 
void StartAutoRate (double period)
 Start running the automatic SPI transfer engine at a periodic rate. More...
 
void StartAutoTrigger (DigitalSource &source, bool rising, bool falling)
 Start running the automatic SPI transfer engine when a trigger occurs. More...
 
void StopAuto ()
 Stop running the automatic SPI transfer engine.
 
void ForceAutoRead ()
 Force the engine to make a single transfer.
 
int ReadAutoReceivedData (uint32_t *buffer, int numToRead, double timeout)
 Read data that has been transferred by the automatic SPI transfer engine. More...
 
int GetAutoDroppedCount ()
 Get the number of bytes dropped by the automatic SPI transfer engine due to the receive buffer being full. More...
 
void InitAccumulator (double period, int cmd, int xferSize, int validMask, int validValue, int dataShift, int dataSize, bool isSigned, bool bigEndian)
 Initialize the accumulator. More...
 
void FreeAccumulator ()
 Frees the accumulator.
 
void ResetAccumulator ()
 Resets the accumulator to zero.
 
void SetAccumulatorCenter (int center)
 Set the center value of the accumulator. More...
 
void SetAccumulatorDeadband (int deadband)
 Set the accumulator's deadband.
 
int GetAccumulatorLastValue () const
 Read the last value read by the accumulator engine.
 
int64_t GetAccumulatorValue () const
 Read the accumulated value. More...
 
int64_t GetAccumulatorCount () const
 Read the number of accumulated values. More...
 
double GetAccumulatorAverage () const
 Read the average of the accumulated value. More...
 
void GetAccumulatorOutput (int64_t &value, int64_t &count) const
 Read the accumulated value and the number of accumulated values atomically. More...
 
void SetAccumulatorIntegratedCenter (double center)
 Set the center value of the accumulator integrator. More...
 
double GetAccumulatorIntegratedValue () const
 Read the integrated value. More...
 
double GetAccumulatorIntegratedAverage () const
 Read the average of the integrated value. 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...
 

Protected Attributes

HAL_SPIPort m_port = HAL_SPI_kInvalid
 
bool m_msbFirst = false
 
bool m_sampleOnTrailing = false
 
bool m_clockIdleHigh = false
 
- Protected Attributes inherited from frc::ErrorBase
Error m_error
 

Additional Inherited Members

- 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.
 

Detailed Description

SPI bus interface class.

This class is intended to be used by sensor (and other SPI device) drivers. It probably should not be used directly.

Constructor & Destructor Documentation

frc::SPI::SPI ( Port  port)
explicit

Constructor.

Parameters
portthe physical SPI port

Member Function Documentation

double frc::SPI::GetAccumulatorAverage ( ) const

Read the average of the accumulated value.

Returns
The accumulated average value (value / count).
int64_t frc::SPI::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.
double frc::SPI::GetAccumulatorIntegratedAverage ( ) const

Read the average of the integrated value.

This is the sum of (each value times the time between values), divided by the count.

Returns
The average of the integrated value accumulated since the last Reset().
double frc::SPI::GetAccumulatorIntegratedValue ( ) const

Read the integrated value.

This is the sum of (each value * time between values).

Returns
The integrated value accumulated since the last Reset().
void frc::SPI::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 atomically. This can be used for averaging.

Parameters
valuePointer to the 64-bit accumulated output.
countPointer to the number of accumulation cycles.
int64_t frc::SPI::GetAccumulatorValue ( ) const

Read the accumulated value.

Returns
The 64-bit value accumulated since the last Reset().
int frc::SPI::GetAutoDroppedCount ( )

Get the number of bytes dropped by the automatic SPI transfer engine due to the receive buffer being full.

Returns
Number of bytes dropped
void frc::SPI::InitAccumulator ( double  period,
int  cmd,
int  xferSize,
int  validMask,
int  validValue,
int  dataShift,
int  dataSize,
bool  isSigned,
bool  bigEndian 
)

Initialize the accumulator.

Parameters
periodTime between reads
cmdSPI command to send to request data
xferSizeSPI transfer size, in bytes
validMaskMask to apply to received data for validity checking
validDataAfter valid_mask is applied, required matching value for validity checking
dataShiftBit shift to apply to received data to get actual data value
dataSizeSize (in bits) of data field
isSignedIs data field signed?
bigEndianIs device big endian?
void frc::SPI::InitAuto ( int  bufferSize)

Initialize automatic SPI transfer engine.

Only a single engine is available, and use of it blocks use of all other chip select usage on the same physical SPI port while it is running.

Parameters
bufferSizebuffer size in bytes
virtual int frc::SPI::Read ( bool  initiate,
uint8_t *  dataReceived,
int  size 
)
virtual

Read a word from the receive FIFO.

Waits for the current transfer to complete if the receive FIFO is empty.

If the receive FIFO is empty, there is no active transfer, and initiate is false, errors.

Parameters
initiateIf true, this function pushes "0" into the transmit buffer and initiates a transfer. If false, this function assumes that data is already in the receive FIFO from a previous write.
int frc::SPI::ReadAutoReceivedData ( uint32_t *  buffer,
int  numToRead,
double  timeout 
)

Read data that has been transferred by the automatic SPI transfer engine.

Transfers may be made a byte at a time, so it's necessary for the caller to handle cases where an entire transfer has not been completed.

Each received data sequence consists of a timestamp followed by the received data bytes, one byte per word (in the least significant byte). The length of each received data sequence is the same as the combined size of the data and zeroSize set in SetAutoTransmitData().

Blocks until numToRead words have been read or timeout expires. May be called with numToRead=0 to retrieve how many words are available.

Parameters
bufferbuffer where read words are stored
numToReadnumber of words to read
timeouttimeout in seconds (ms resolution)
Returns
Number of words remaining to be read
void frc::SPI::SetAccumulatorCenter ( int  center)

Set the center value of the accumulator.

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

void frc::SPI::SetAccumulatorIntegratedCenter ( double  center)

Set the center value of the accumulator integrator.

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

void frc::SPI::SetAutoTransmitData ( wpi::ArrayRef< uint8_t >  dataToSend,
int  zeroSize 
)

Set the data to be transmitted by the engine.

Up to 16 bytes are configurable, and may be followed by up to 127 zero bytes.

Parameters
dataToSenddata to send (maximum 16 bytes)
zeroSizenumber of zeros to send after the data
void frc::SPI::SetClockActiveHigh ( )

Configure the clock output line to be active high.

This is sometimes called clock polarity low or clock idle low.

void frc::SPI::SetClockActiveLow ( )

Configure the clock output line to be active low.

This is sometimes called clock polarity high or clock idle high.

void frc::SPI::SetClockRate ( double  hz)

Configure the rate of the generated clock signal.

The default value is 500,000Hz. The maximum value is 4,000,000Hz.

Parameters
hzThe clock rate in Hertz.
void frc::SPI::StartAutoRate ( double  period)

Start running the automatic SPI transfer engine at a periodic rate.

InitAuto() and SetAutoTransmitData() must be called before calling this function.

Parameters
periodperiod between transfers, in seconds (us resolution)
void frc::SPI::StartAutoTrigger ( DigitalSource source,
bool  rising,
bool  falling 
)

Start running the automatic SPI transfer engine when a trigger occurs.

InitAuto() and SetAutoTransmitData() must be called before calling this function.

Parameters
sourcedigital source for the trigger (may be an analog trigger)
risingtrigger on the rising edge
fallingtrigger on the falling edge
virtual int frc::SPI::Transaction ( uint8_t *  dataToSend,
uint8_t *  dataReceived,
int  size 
)
virtual

Perform a simultaneous read/write transaction with the device.

Parameters
dataToSendThe data to be written out to the device
dataReceivedBuffer to receive data from the device
sizeThe length of the transaction, in bytes
virtual int frc::SPI::Write ( uint8_t *  data,
int  size 
)
virtual

Write data to the slave device.

Blocks until there is space in the output FIFO.

If not running in output only mode, also saves the data received on the MISO input during the transfer into the receive FIFO.


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