LSM9DS1.cpp

/*
  This file is part of the Arduino_LSM9DS1 library.
  Copyright (c) 2019 Arduino SA. All rights reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "LSM9DS1.h"

#define LSM9DS1_ADDRESS            0x6b

#define LSM9DS1_WHO_AM_I           0x0f
#define LSM9DS1_CTRL_REG1_G        0x10
#define LSM9DS1_STATUS_REG         0x17
#define LSM9DS1_OUT_X_G            0x18
#define LSM9DS1_CTRL_REG6_XL       0x20
#define LSM9DS1_CTRL_REG8          0x22
#define LSM9DS1_OUT_X_XL           0x28

// magnetometer
#define LSM9DS1_ADDRESS_M          0x1e

#define LSM9DS1_CTRL_REG1_M        0x20
#define LSM9DS1_CTRL_REG2_M        0x21
#define LSM9DS1_CTRL_REG3_M        0x22
#define LSM9DS1_STATUS_REG_M       0x27
#define LSM9DS1_OUT_X_L_M          0x28

LSM9DS1Class::LSM9DS1Class(TwoWire& wire) :
  continuousMode(false), _wire(&wire)
{
}

LSM9DS1Class::~LSM9DS1Class()
{
}

int LSM9DS1Class::begin()
{
  _wire->begin();

  // reset
  writeRegister(LSM9DS1_ADDRESS, LSM9DS1_CTRL_REG8, 0x05);
  writeRegister(LSM9DS1_ADDRESS_M, LSM9DS1_CTRL_REG2_M, 0x0c);

  delay(10);

  if (readRegister(LSM9DS1_ADDRESS, LSM9DS1_WHO_AM_I) != 0x68) {
    end();

    return 0;
  }

  if (readRegister(LSM9DS1_ADDRESS_M, LSM9DS1_WHO_AM_I) != 0x3d) {
    end();

    return 0;
  }

  writeRegister(LSM9DS1_ADDRESS, LSM9DS1_CTRL_REG1_G, 0x78); // 119 Hz, 2000 dps, 16 Hz BW
  writeRegister(LSM9DS1_ADDRESS, LSM9DS1_CTRL_REG6_XL, 0x70); // 119 Hz, 4g

  writeRegister(LSM9DS1_ADDRESS_M, LSM9DS1_CTRL_REG1_M, 0xb4); // Temperature compensation enable, medium performance, 20 Hz
  writeRegister(LSM9DS1_ADDRESS_M, LSM9DS1_CTRL_REG2_M, 0x00); // 4 gauss
  writeRegister(LSM9DS1_ADDRESS_M, LSM9DS1_CTRL_REG3_M, 0x00); // Continuous conversion mode

  return 1;
}

void LSM9DS1Class::setContinuousMode() {
  // Enable FIFO (see docs https://www.st.com/resource/en/datasheet/DM00103319.pdf)
  writeRegister(LSM9DS1_ADDRESS, 0x23, 0x02);
  // Set continuous mode
  writeRegister(LSM9DS1_ADDRESS, 0x2E, 0xC0);

  continuousMode = true;
}

void LSM9DS1Class::setOneShotMode() {
  // Disable FIFO (see docs https://www.st.com/resource/en/datasheet/DM00103319.pdf)
  writeRegister(LSM9DS1_ADDRESS, 0x23, 0x00);
  // Disable continuous mode
  writeRegister(LSM9DS1_ADDRESS, 0x2E, 0x00);

  continuousMode = false;
}

void LSM9DS1Class::end()
{
  writeRegister(LSM9DS1_ADDRESS_M, LSM9DS1_CTRL_REG3_M, 0x03);
  writeRegister(LSM9DS1_ADDRESS, LSM9DS1_CTRL_REG1_G, 0x00);
  writeRegister(LSM9DS1_ADDRESS, LSM9DS1_CTRL_REG6_XL, 0x00);

  _wire->end();
}

int LSM9DS1Class::readAcceleration(float& x, float& y, float& z)
{
  int16_t data[3];

  if (!readRegisters(LSM9DS1_ADDRESS, LSM9DS1_OUT_X_XL, (uint8_t*)data, sizeof(data))) {
    x = NAN;
    y = NAN;
    z = NAN;

    return 0;
  }

  x = data[0] * 4.0 / 32768.0;
  y = data[1] * 4.0 / 32768.0;
  z = data[2] * 4.0 / 32768.0;

  return 1;
}

int LSM9DS1Class::accelerationAvailable()
{
  if (continuousMode) {
    // Read FIFO_SRC. If any of the rightmost 8 bits have a value, there is data.
    if (readRegister(LSM9DS1_ADDRESS, 0x2F) & 63) {
      return 1;
    }
  } else {
    if (readRegister(LSM9DS1_ADDRESS, LSM9DS1_STATUS_REG) & 0x01) {
      return 1;
    }
  }

  return 0;
}

float LSM9DS1Class::accelerationSampleRate()
{
  return 119.0F;
}

int LSM9DS1Class::readGyroscope(float& x, float& y, float& z)
{
  int16_t data[3];

  if (!readRegisters(LSM9DS1_ADDRESS, LSM9DS1_OUT_X_G, (uint8_t*)data, sizeof(data))) {
    x = NAN;
    y = NAN;
    z = NAN;

    return 0;
  }

  x = data[0] * 2000.0 / 32768.0;
  y = data[1] * 2000.0 / 32768.0;
  z = data[2] * 2000.0 / 32768.0;

  return 1;
}

int LSM9DS1Class::gyroscopeAvailable()
{
  if (readRegister(LSM9DS1_ADDRESS, LSM9DS1_STATUS_REG) & 0x02) {
    return 1;
  }

  return 0;
}

float LSM9DS1Class::gyroscopeSampleRate()
{
  return 119.0F;
}

int LSM9DS1Class::readMagneticField(float& x, float& y, float& z)
{
  int16_t data[3];

  if (!readRegisters(LSM9DS1_ADDRESS_M, LSM9DS1_OUT_X_L_M, (uint8_t*)data, sizeof(data))) {
    x = NAN;
    y = NAN;
    z = NAN;

    return 0;
  }

  x = data[0] * 4.0 * 100.0 / 32768.0;
  y = data[1] * 4.0 * 100.0 / 32768.0;
  z = data[2] * 4.0 * 100.0 / 32768.0;

  return 1;
}

int LSM9DS1Class::magneticFieldAvailable()
{
  if (readRegister(LSM9DS1_ADDRESS_M, LSM9DS1_STATUS_REG_M) & 0x08) {
    return 1;
  }

  return 0;
}

float LSM9DS1Class::magneticFieldSampleRate()
{
  return 20.0;
}

int LSM9DS1Class::readRegister(uint8_t slaveAddress, uint8_t address)
{
  _wire->beginTransmission(slaveAddress);
  _wire->write(address);
  if (_wire->endTransmission() != 0) {
    return -1;
  }

  if (_wire->requestFrom(slaveAddress, 1) != 1) {
    return -1;
  }

  return _wire->read();
}

int LSM9DS1Class::readRegisters(uint8_t slaveAddress, uint8_t address, uint8_t* data, size_t length)
{
  _wire->beginTransmission(slaveAddress);
  _wire->write(0x80 | address);
  if (_wire->endTransmission(false) != 0) {
    return -1;
  }

  if (_wire->requestFrom(slaveAddress, length) != length) {
    return 0;
  }

  for (size_t i = 0; i < length; i++) {
    *data++ = _wire->read();
  }

  return 1;
}

int LSM9DS1Class::writeRegister(uint8_t slaveAddress, uint8_t address, uint8_t value)
{
  _wire->beginTransmission(slaveAddress);
  _wire->write(address);
  _wire->write(value);
  if (_wire->endTransmission() != 0) {
    return 0;
  }

  return 1;
}

#ifdef ARDUINO_ARDUINO_NANO33BLE
LSM9DS1Class IMU_LSM9DS1(Wire1);
#else
LSM9DS1Class IMU_LSM9DS1(Wire);
#endif