allwpilib/wpilibc/src/main/native/cpp/SPI.cpp

/*----------------------------------------------------------------------------*/
/* Copyright (c) 2008-2017 FIRST. All Rights Reserved.                        */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

#include "SPI.h"

#include <cstring>

#include <HAL/HAL.h>
#include <HAL/SPI.h>
#include <llvm/SmallVector.h>

#include "WPIErrors.h"

using namespace frc;

/**
 * Constructor
 *
 * @param port the physical SPI port
 */
SPI::SPI(Port port) : m_port(static_cast<HAL_SPIPort>(port)) {
  int32_t status = 0;
  HAL_InitializeSPI(m_port, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));

  static int instances = 0;
  instances++;
  HAL_Report(HALUsageReporting::kResourceType_SPI, instances);
}

/**
 * Destructor.
 */
SPI::~SPI() { HAL_CloseSPI(m_port); }

/**
 * Configure the rate of the generated clock signal.
 *
 * The default value is 500,000Hz.
 * The maximum value is 4,000,000Hz.
 *
 * @param hz The clock rate in Hertz.
 */
void SPI::SetClockRate(double hz) { HAL_SetSPISpeed(m_port, hz); }

/**
 * Configure the order that bits are sent and received on the wire
 * to be most significant bit first.
 */
void SPI::SetMSBFirst() {
  m_msbFirst = true;
  HAL_SetSPIOpts(m_port, m_msbFirst, m_sampleOnTrailing, m_clk_idle_high);
}

/**
 * Configure the order that bits are sent and received on the wire
 * to be least significant bit first.
 */
void SPI::SetLSBFirst() {
  m_msbFirst = false;
  HAL_SetSPIOpts(m_port, m_msbFirst, m_sampleOnTrailing, m_clk_idle_high);
}

/**
 * Configure that the data is stable on the falling edge and the data
 * changes on the rising edge.
 */
void SPI::SetSampleDataOnFalling() {
  m_sampleOnTrailing = true;
  HAL_SetSPIOpts(m_port, m_msbFirst, m_sampleOnTrailing, m_clk_idle_high);
}

/**
 * Configure that the data is stable on the rising edge and the data
 * changes on the falling edge.
 */
void SPI::SetSampleDataOnRising() {
  m_sampleOnTrailing = false;
  HAL_SetSPIOpts(m_port, m_msbFirst, m_sampleOnTrailing, m_clk_idle_high);
}

/**
 * Configure the clock output line to be active low.
 * This is sometimes called clock polarity high or clock idle high.
 */
void SPI::SetClockActiveLow() {
  m_clk_idle_high = true;
  HAL_SetSPIOpts(m_port, m_msbFirst, m_sampleOnTrailing, m_clk_idle_high);
}

/**
 * Configure the clock output line to be active high.
 * This is sometimes called clock polarity low or clock idle low.
 */
void SPI::SetClockActiveHigh() {
  m_clk_idle_high = false;
  HAL_SetSPIOpts(m_port, m_msbFirst, m_sampleOnTrailing, m_clk_idle_high);
}

/**
 * Configure the chip select line to be active high.
 */
void SPI::SetChipSelectActiveHigh() {
  int32_t status = 0;
  HAL_SetSPIChipSelectActiveHigh(m_port, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
}

/**
 * Configure the chip select line to be active low.
 */
void SPI::SetChipSelectActiveLow() {
  int32_t status = 0;
  HAL_SetSPIChipSelectActiveLow(m_port, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
}

/**
 * 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.
 */
int SPI::Write(uint8_t* data, int size) {
  int retVal = 0;
  retVal = HAL_WriteSPI(m_port, data, size);
  return retVal;
}

/**
 * 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.
 *
 * @param 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.
 */
int SPI::Read(bool initiate, uint8_t* dataReceived, int size) {
  int retVal = 0;
  if (initiate) {
    llvm::SmallVector<uint8_t, 32> dataToSend;
    dataToSend.resize(size);
    retVal = HAL_TransactionSPI(m_port, dataToSend.data(), dataReceived, size);
  } else {
    retVal = HAL_ReadSPI(m_port, dataReceived, size);
  }
  return retVal;
}

/**
 * Perform a simultaneous read/write transaction with the device
 *
 * @param dataToSend   The data to be written out to the device
 * @param dataReceived Buffer to receive data from the device
 * @param size         The length of the transaction, in bytes
 */
int SPI::Transaction(uint8_t* dataToSend, uint8_t* dataReceived, int size) {
  int retVal = 0;
  retVal = HAL_TransactionSPI(m_port, dataToSend, dataReceived, size);
  return retVal;
}

/**
 * Initialize the accumulator.
 *
 * @param period    Time between reads
 * @param cmd       SPI command to send to request data
 * @param xferSize  SPI transfer size, in bytes
 * @param validMask Mask to apply to received data for validity checking
 * @param validData After valid_mask is applied, required matching value for
 *                  validity checking
 * @param dataShift Bit shift to apply to received data to get actual data
 *                  value
 * @param dataSize  Size (in bits) of data field
 * @param isSigned  Is data field signed?
 * @param bigEndian Is device big endian?
 */
void SPI::InitAccumulator(double period, int cmd, int xferSize, int validMask,
                          int validValue, int dataShift, int dataSize,
                          bool isSigned, bool bigEndian) {
  int32_t status = 0;
  HAL_InitSPIAccumulator(m_port, static_cast<int32_t>(period * 1e6), cmd,
                         xferSize, validMask, validValue, dataShift, dataSize,
                         isSigned, bigEndian, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
}

/**
 * Frees the accumulator.
 */
void SPI::FreeAccumulator() {
  int32_t status = 0;
  HAL_FreeSPIAccumulator(m_port, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
}

/**
 * Resets the accumulator to zero.
 */
void SPI::ResetAccumulator() {
  int32_t status = 0;
  HAL_ResetSPIAccumulator(m_port, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
}

/**
 * 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 SPI::SetAccumulatorCenter(int center) {
  int32_t status = 0;
  HAL_SetSPIAccumulatorCenter(m_port, center, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
}

/**
 * Set the accumulator's deadband.
 */
void SPI::SetAccumulatorDeadband(int deadband) {
  int32_t status = 0;
  HAL_SetSPIAccumulatorDeadband(m_port, deadband, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
}

/**
 * Read the last value read by the accumulator engine.
 */
int SPI::GetAccumulatorLastValue() const {
  int32_t status = 0;
  int retVal = HAL_GetSPIAccumulatorLastValue(m_port, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
  return retVal;
}

/**
 * Read the accumulated value.
 *
 * @return The 64-bit value accumulated since the last Reset().
 */
int64_t SPI::GetAccumulatorValue() const {
  int32_t status = 0;
  int64_t retVal = HAL_GetSPIAccumulatorValue(m_port, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
  return retVal;
}

/**
 * Read the number of accumulated values.
 *
 * Read the count of the accumulated values since the accumulator was last
 * Reset().
 *
 * @return The number of times samples from the channel were accumulated.
 */
int64_t SPI::GetAccumulatorCount() const {
  int32_t status = 0;
  int64_t retVal = HAL_GetSPIAccumulatorCount(m_port, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
  return retVal;
}

/**
 * Read the average of the accumulated value.
 *
 * @return The accumulated average value (value / count).
 */
double SPI::GetAccumulatorAverage() const {
  int32_t status = 0;
  double retVal = HAL_GetSPIAccumulatorAverage(m_port, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
  return retVal;
}

/**
 * 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.
 *
 * @param value Pointer to the 64-bit accumulated output.
 * @param count Pointer to the number of accumulation cycles.
 */
void SPI::GetAccumulatorOutput(int64_t& value, int64_t& count) const {
  int32_t status = 0;
  HAL_GetSPIAccumulatorOutput(m_port, &value, &count, &status);
  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
}