allwpilib/wpilibc/wpilibC++/lib/ADXL345_SPI.cpp

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2008. 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 $(WIND_BASE)/WPILib.  */
/*----------------------------------------------------------------------------*/

#include "ADXL345_SPI.h"
#include "DigitalInput.h"
#include "DigitalOutput.h"
#include "SPI.h"

const uint8_t ADXL345_SPI::kPowerCtlRegister;
const uint8_t ADXL345_SPI::kDataFormatRegister;
const uint8_t ADXL345_SPI::kDataRegister;
constexpr double ADXL345_SPI::kGsPerLSB;

ADXL345_SPI::ADXL345_SPI(SPI::Port port, ADXL345_SPI::Range range)
{
	m_port = port;
	Init(range);
}

/**
 * Internal common init function.
 */
void ADXL345_SPI::Init(Range range)
{
		m_spi = new SPI(m_port);
		m_spi->SetClockRate(500000);
		m_spi->SetMSBFirst();
		m_spi->SetSampleDataOnFalling();
		m_spi->SetClockActiveLow();
		m_spi->SetChipSelectActiveHigh();

		uint8_t commands[2];
		// Turn on the measurements
		commands[0] = kPowerCtlRegister;
		commands[1] = kPowerCtl_Measure;
		m_spi->Transaction(commands, commands, 2);

		SetRange(range);

		HALReport(HALUsageReporting::kResourceType_ADXL345, HALUsageReporting::kADXL345_SPI);
}

/**
 * Destructor.
 */
ADXL345_SPI::~ADXL345_SPI()
{
	delete m_spi;
	m_spi = NULL;
}

/** {@inheritdoc} */
void ADXL345_SPI::SetRange(Range range)
{
	uint8_t commands[2];
	
	// Specify the data format to read
	commands[0] = kDataFormatRegister;
	commands[1] = kDataFormat_FullRes| (uint8_t)(range & 0x03);
	m_spi->Transaction(commands, commands, 2);
}

/** {@inheritdoc} */
double ADXL345_SPI::GetX()
{
	return GetAcceleration(kAxis_X);
}

/** {@inheritdoc} */
double ADXL345_SPI::GetY()
{
	return GetAcceleration(kAxis_Y);
}

/** {@inheritdoc} */
double ADXL345_SPI::GetZ()
{
	return GetAcceleration(kAxis_Z);
}

/**
 * Get the acceleration of one axis in Gs.
 *
 * @param axis The axis to read from.
 * @return Acceleration of the ADXL345 in Gs.
 */
double ADXL345_SPI::GetAcceleration(ADXL345_SPI::Axes axis)
{
	int16_t rawAccel = 0;
	if(m_spi)
	{
		uint8_t buffer[3];
		uint8_t command[3] = {0,0,0};
		command[0] = (kAddress_Read | kAddress_MultiByte | kDataRegister) + (uint8_t)axis;
		m_spi->Transaction(command, buffer, 3);

		// Sensor is little endian... swap bytes
		rawAccel = buffer[2]<<8 | buffer[1];
	}
	return rawAccel * kGsPerLSB;
}

/**
 * Get the acceleration of all axes in Gs.
 *
 * @return Acceleration measured on all axes of the ADXL345 in Gs.
 */
ADXL345_SPI::AllAxes ADXL345_SPI::GetAccelerations()
{
	AllAxes data = AllAxes();
	uint8_t dataBuffer[7] = {0,0,0,0,0,0,0};
	int16_t rawData[3];
	if (m_spi)
	{
		// Select the data address.
		dataBuffer[0] = (kAddress_Read | kAddress_MultiByte | kDataRegister);
		m_spi->Transaction(dataBuffer, dataBuffer, 7);

		for (int32_t i=0; i<3; i++)
		{
			// Sensor is little endian... swap bytes
			rawData[i] = dataBuffer[i*2+2] << 8 | dataBuffer[i*2+1];
		}

		data.XAxis = rawData[0] * kGsPerLSB;
		data.YAxis = rawData[1] * kGsPerLSB;
		data.ZAxis = rawData[2] * kGsPerLSB;
	}
	return data;
}