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/**
 * @file FXOS8700CQ.cpp
 * @date June 5th, 2016
 * @author Weimen Li
 * @brief Source file for FXOS8700CQ driver.
 */

#include <FXOS8700CQ.hpp>

// These defines are extracted from Page. 25 of the datasheet, Rev. 7.0.
// FXOS8700CQ I2C address
const uint8_t FXOS8700CQ_SLAVE_ADDR = 0x1C; // with pins SA1=1, SA0=0, preshifted

// FXOS8700CQ internal register addresses
const char FXOS8700CQ_STATUS = 0x00;
const char FXOS8700CQ_OUT_X_MSB = 0x01;
const uint8_t FXOS8700CQ_WHOAMI = 0x0D;
const uint8_t FXOS8700CQ_XYZ_DATA_CFG = 0x0E;
const uint8_t FXOS8700CQ_CTRL_REG1 = 0x2A;
const uint8_t FXOS8700CQ_CTRL_REG2 = 0x2B;
const uint8_t FXOS8700CQ_CTRL_REG4 = 0x2D; /// Interrupt enable register.
const uint8_t FXOS8700CQ_CTRL_REG5 = 0x2E; /// Interrupt pin register.
const uint8_t FXOS8700CQ_M_CTRL_REG1 = 0x5B;
const uint8_t FXOS8700CQ_M_CTRL_REG2 = 0x5C;
const uint8_t FXOS8700CQ_WHOAMI_VAL = 0xC7;

// Other defines:
static const uint32_t I2CFastModeHz = 400000;
static const uint32_t I2CNormalModeHz = 100000;
static const uint32_t I2CSuperSlowModeHz = 25000;

FXOS8700CQ::FXOS8700CQ(PinName SDA, PinName SCL, PinName INT1, PinName INT2, AccelerometerSensitivity setting)
: I2CObj(SDA, SCL), dataReadyInt(INT2), accelSensitivitySetting(setting),
  accelInt2Float((accelSensitivitySetting == TWO) ? 1. / 4096. :
		  	  	 (accelSensitivitySetting == FOUR) ? 1. / 2048. : 1. / 1024.),
		  	  	 xOffset(0), yOffset(0), zOffset(0)
{

	// Set the bus to operate in fast or normal mode.
	I2CObj.frequency(I2CFastModeHz);

	// Following routine is based off of manufacturer's datasheet example.
	// Create a buffer to hold information to be transfered.
	char dataPacket[64];

	/* Reset the device, placing it into standby mode, to set registers. */
	// standby
	// [6] = reset = 1;
	dataPacket[0] = FXOS8700CQ_CTRL_REG2; // First byte is register address.
	dataPacket[1] = 0b01000000; // Second byte is data - bit 6 set to 1 means reset.
	I2CObj.write(FXOS8700CQ_SLAVE_ADDR, dataPacket, 2);
	// Wait 2 ms for the reset to take place.
	wait_ms(2);
	//I2CObj.stop();

	/* Configure the device to send an interrupt when data is ready. */
	//[7-1]: Disable all other interrupt sources.
	//[0]: Enable data-ready interrupt with 1.
	dataPacket[0] = FXOS8700CQ_CTRL_REG4; // First byte is register address.
	dataPacket[1] = 0b00000001;
	I2CObj.write(FXOS8700CQ_SLAVE_ADDR, dataPacket, 2);
	//I2CObj.stop();
	/* Configure the data-ready interrupt to be on INT2 Pin. */
	//[7-1]: Other interrupt source pin assignment - we don't care because we only use the data ready interrupt.
	//[0]: Set to 0 for data-ready interrupt to be on INT2.
	dataPacket[0] = FXOS8700CQ_CTRL_REG5; // First byte is register address.
	dataPacket[1] = 0b00000000;
	I2CObj.write(FXOS8700CQ_SLAVE_ADDR, dataPacket, 2);
	//I2CObj.stop();

	/* Disable the magnetometer. */
	// write 0001 1111 = 0x1F to magnetometer control register 1
	// [7]: m_acal=0: auto calibration disabled
	// [6]: m_rst=0: no one-shot magnetic reset
	// [5]: m_ost=0: no one-shot magnetic measurement
	// [4-2]: m_os=111=7: 8x oversampling (for 200Hz) to reduce magnetometer noise
	// [1-0]: m_hms=00=0: only set the accelerometer to be active.
	dataPacket[0] = FXOS8700CQ_M_CTRL_REG1; // First byte is register address.
	dataPacket[1] = 0b00011100; // Second byte is data.
	I2CObj.write(FXOS8700CQ_SLAVE_ADDR, dataPacket, 2);
	//I2CObj.stop();


	/* Configure the device to disable the high-pass filter and
	 * use the setrange.
	 */
	// [7]: reserved
	// [6]: reserved
	// [5]: reserved
	// [4]: High pass filter filter disabled with 0.
	// [3]: reserved
	// [2]: reserved
	// [1-0]: fs=10 for accelerometer range of +/-8g range with 0.976mg/LSB
	uint8_t fs =
			(accelSensitivitySetting == TWO) ? 0b00 :
			(accelSensitivitySetting == FOUR) ? 0b01 :
					0b10;
	dataPacket[0] = FXOS8700CQ_XYZ_DATA_CFG; // First byte is register address.
	dataPacket[1] = 0b00000000 | fs; // Second byte is data.
	I2CObj.write(FXOS8700CQ_SLAVE_ADDR, dataPacket, 2);
	//I2CObj.stop();
	/*
	 * Set the device out of standby mode.
	 */
	// [7-6]: aslp_rate=00 // Sleep mode output data rate is 50 Hz.
	// [5-3]: dr=000 for 800Hz data rate in accelerometer only mode.
	// [2]: lnoise=... for non-low noise mode (Low noise only possible for 2 g or 4 g accelerometer range.)
	// [1]: f_read=0 for normal 16 bit reads
	// [0]: active=1 to take the part out of standby and enable sampling
	uint8_t lNoise = (accelSensitivitySetting != EIGHT) ? 0b100 : 0b000;
	dataPacket[0] = FXOS8700CQ_CTRL_REG1; // First byte is register address.
	dataPacket[1] = 0b00000001 | lNoise; // Second byte is data.
	I2CObj.write(FXOS8700CQ_SLAVE_ADDR, dataPacket, 2);
	//I2CObj.stop();

	// Attach the data-ready interrupt to a member interrupt handler.
	// Interrupts are active-low by default.
	dataReadyInt.fall(this, &FXOS8700CQ::dataReadyISR);

}

FXOS8700CQ::~FXOS8700CQ() {
	// TODO Auto-generated destructor stub
}

void FXOS8700CQ::readAccelerometer(float *xAccel, float *yAccel, float *zAccel) {
	// In case an interrupt occurs in the middle of our write, we spin while the data is not consistent.
	while((*xAccel != lastxAccel) || (*yAccel != lastyAccel) || (*zAccel != lastzAccel)) {
		*xAccel = lastxAccel;
		*yAccel = lastyAccel;
		*zAccel = lastzAccel;
	}
}

void FXOS8700CQ::dataReadyISR(void) {
	char inputBuffer[7];
	I2CObj.write(FXOS8700CQ_SLAVE_ADDR, &FXOS8700CQ_STATUS, 1);
	// Read the accelerometer values back from the slave.
	I2CObj.read(FXOS8700CQ_SLAVE_ADDR, inputBuffer,7);

	// copy the 14 bit accelerometer byte data into 16 bit words
	lastxAccel = accelInt2Float * ((int16_t) ((inputBuffer[1] << 8) | inputBuffer[2]) >> 2) - xOffset;
	lastyAccel = accelInt2Float * ((int16_t) ((inputBuffer[3] << 8) | inputBuffer[4]) >> 2) - yOffset;
	lastzAccel = accelInt2Float * ((int16_t) ((inputBuffer[5] << 8) | inputBuffer[6]) >> 2) - zOffset;
}