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WPILibC++ 2024.3.2
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SPI bus interface class. More...
#include <frc/SPI.h>
Public Types | |
enum | Port { kOnboardCS0 = 0 , kOnboardCS1 , kOnboardCS2 , kOnboardCS3 , kMXP } |
SPI port. More... | |
enum | Mode { kMode0 = HAL_SPI_kMode0 , kMode1 = HAL_SPI_kMode1 , kMode2 = HAL_SPI_kMode2 , kMode3 = HAL_SPI_kMode3 } |
SPI mode. More... | |
Public Member Functions | |
SPI (Port port) | |
Constructor. More... | |
virtual | ~SPI () |
SPI (SPI &&)=default | |
SPI & | operator= (SPI &&)=default |
Port | GetPort () const |
Returns the SPI port. More... | |
void | SetClockRate (int hz) |
Configure the rate of the generated clock signal. More... | |
void | SetMode (Mode mode) |
Sets the mode for the SPI device. More... | |
void | SetChipSelectActiveHigh () |
Configure the chip select line to be active high. More... | |
void | SetChipSelectActiveLow () |
Configure the chip select line to be active low. More... | |
virtual int | Write (uint8_t *data, int size) |
Write data to the peripheral 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. More... | |
void | SetAutoTransmitData (std::span< const uint8_t > dataToSend, int zeroSize) |
Set the data to be transmitted by the engine. More... | |
void | StartAutoRate (units::second_t 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. More... | |
void | ForceAutoRead () |
Force the engine to make a single transfer. More... | |
int | ReadAutoReceivedData (uint32_t *buffer, int numToRead, units::second_t 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 | ConfigureAutoStall (HAL_SPIPort port, int csToSclkTicks, int stallTicks, int pow2BytesPerRead) |
Configure the Auto SPI Stall time between reads. More... | |
void | InitAccumulator (units::second_t 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. More... | |
void | ResetAccumulator () |
Resets the accumulator to zero. More... | |
void | SetAccumulatorCenter (int center) |
Set the center value of the accumulator. More... | |
void | SetAccumulatorDeadband (int deadband) |
Set the accumulator's deadband. More... | |
int | GetAccumulatorLastValue () const |
Read the last value read by the accumulator engine. More... | |
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... | |
Protected Attributes | |
hal::SPIPort | m_port |
HAL_SPIMode | m_mode = HAL_SPIMode::HAL_SPI_kMode0 |
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.
enum frc::SPI::Mode |
SPI mode.
enum frc::SPI::Port |
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void frc::SPI::ConfigureAutoStall | ( | HAL_SPIPort | port, |
int | csToSclkTicks, | ||
int | stallTicks, | ||
int | pow2BytesPerRead | ||
) |
Configure the Auto SPI Stall time between reads.
port | The number of the port to use. 0-3 for Onboard CS0-CS2, 4 for MXP. |
csToSclkTicks | the number of ticks to wait before asserting the cs pin |
stallTicks | the number of ticks to stall for |
pow2BytesPerRead | the number of bytes to read before stalling |
void frc::SPI::ForceAutoRead | ( | ) |
Force the engine to make a single transfer.
void frc::SPI::FreeAccumulator | ( | ) |
Frees the accumulator.
void frc::SPI::FreeAuto | ( | ) |
Frees the automatic SPI transfer engine.
double frc::SPI::GetAccumulatorAverage | ( | ) | const |
Read the average of the accumulated value.
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().
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.
double frc::SPI::GetAccumulatorIntegratedValue | ( | ) | const |
Read the integrated value.
This is the sum of (each value * time between values).
int frc::SPI::GetAccumulatorLastValue | ( | ) | const |
Read the last value read by the accumulator engine.
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.
value | Pointer to the 64-bit accumulated output. |
count | Pointer to the number of accumulation cycles. |
int64_t frc::SPI::GetAccumulatorValue | ( | ) | const |
Read the accumulated value.
int frc::SPI::GetAutoDroppedCount | ( | ) |
Get the number of bytes dropped by the automatic SPI transfer engine due to the receive buffer being full.
void frc::SPI::InitAccumulator | ( | units::second_t | period, |
int | cmd, | ||
int | xferSize, | ||
int | validMask, | ||
int | validValue, | ||
int | dataShift, | ||
int | dataSize, | ||
bool | isSigned, | ||
bool | bigEndian | ||
) |
Initialize the accumulator.
period | Time between reads |
cmd | SPI command to send to request data |
xferSize | SPI transfer size, in bytes |
validMask | Mask to apply to received data for validity checking |
validValue | After valid_mask is applied, required matching value for validity checking |
dataShift | Bit shift to apply to received data to get actual data value |
dataSize | Size (in bits) of data field |
isSigned | Is data field signed? |
bigEndian | Is device big endian? |
void frc::SPI::InitAuto | ( | int | bufferSize | ) |
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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.
initiate | If 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. |
dataReceived | Buffer to receive data from the device |
size | The length of the transaction, in bytes |
int frc::SPI::ReadAutoReceivedData | ( | uint32_t * | buffer, |
int | numToRead, | ||
units::second_t | 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.
buffer | buffer where read words are stored |
numToRead | number of words to read |
timeout | timeout (ms resolution) |
void frc::SPI::ResetAccumulator | ( | ) |
Resets the accumulator to zero.
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::SetAccumulatorDeadband | ( | int | deadband | ) |
Set the accumulator's deadband.
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 | ( | std::span< const 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.
dataToSend | data to send (maximum 16 bytes) |
zeroSize | number of zeros to send after the data |
void frc::SPI::SetChipSelectActiveHigh | ( | ) |
Configure the chip select line to be active high.
void frc::SPI::SetChipSelectActiveLow | ( | ) |
Configure the chip select line to be active low.
void frc::SPI::SetClockRate | ( | int | hz | ) |
Configure the rate of the generated clock signal.
The default value is 500,000Hz. The maximum value is 4,000,000Hz.
hz | The clock rate in Hertz. |
void frc::SPI::SetMode | ( | Mode | mode | ) |
Sets the mode for the SPI device.
Mode 0 is Clock idle low, data sampled on rising edge
Mode 1 is Clock idle low, data sampled on falling edge
Mode 2 is Clock idle high, data sampled on falling edge
Mode 3 is Clock idle high, data sampled on rising edge
mode | The mode to set. |
void frc::SPI::StartAutoRate | ( | units::second_t | period | ) |
Start running the automatic SPI transfer engine at a periodic rate.
InitAuto() and SetAutoTransmitData() must be called before calling this function.
period | period between transfers (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.
source | digital source for the trigger (may be an analog trigger) |
rising | trigger on the rising edge |
falling | trigger on the falling edge |
void frc::SPI::StopAuto | ( | ) |
Stop running the automatic SPI transfer engine.
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Perform a simultaneous read/write transaction with the device.
dataToSend | The data to be written out to the device |
dataReceived | Buffer to receive data from the device |
size | The length of the transaction, in bytes |
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virtual |
Write data to the peripheral device.
Blocks until there is space in the output FIFO.
If not running in output only mode, also saves the data received on the CIPO input during the transfer into the receive FIFO.
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