ardupilot/libraries/AP_InertialSensor/AP_InertialSensor_L3G4200D.cpp

/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
/*
  This is an INS driver for the combination L3G4200D gyro and ADXL345 accelerometer.
  This combination is available as a cheap 10DOF sensor on ebay
 */
// ADXL345 Accelerometer http://www.analog.com/static/imported-files/data_sheets/ADXL345.pdf
// L3G4200D gyro http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/CD00265057.pdf

#include <AP_HAL.h>
#if CONFIG_HAL_BOARD == HAL_BOARD_LINUX

#include <AP_Math.h>
#include "AP_InertialSensor_L3G4200D.h"
#include <stdio.h>
#include <unistd.h>

const extern AP_HAL::HAL& hal;

///////
/// Accelerometer ADXL345 register definitions
#define ADXL345_ACCELEROMETER_ADDRESS                  0x53
#define ADXL345_ACCELEROMETER_XL345_DEVID              0xe5
#define ADXL345_ACCELEROMETER_ADXLREG_BW_RATE          0x2c
#define ADXL345_ACCELEROMETER_ADXLREG_POWER_CTL        0x2d
#define ADXL345_ACCELEROMETER_ADXLREG_DATA_FORMAT      0x31
#define ADXL345_ACCELEROMETER_ADXLREG_DEVID            0x00
#define ADXL345_ACCELEROMETER_ADXLREG_DATAX0           0x32
#define ADXL345_ACCELEROMETER_ADXLREG_FIFO_CTL         0x38
#define ADXL345_ACCELEROMETER_ADXLREG_FIFO_CTL_STREAM     0x9F
#define ADXL345_ACCELEROMETER_ADXLREG_FIFO_STATUS      0x39

// ADXL345 accelerometer scaling
// Result will be scaled to 1m/s/s
// ADXL345 in Full resolution mode (any g scaling) is 256 counts/g, so scale by 9.81/256 = 0.038320312
#define ADXL345_ACCELEROMETER_SCALE_M_S    (GRAVITY_MSS / 256.0f)

/// Gyro ITG3205 register definitions
#define L3G4200D_I2C_ADDRESS                       0x69

#define L3G4200D_REG_WHO_AM_I                      0x0f
#define L3G4200D_REG_WHO_AM_I_VALUE                     0xd3

#define L3G4200D_REG_CTRL_REG1                     0x20
#define L3G4200D_REG_CTRL_REG1_DRBW_800_110             0xf0
#define L3G4200D_REG_CTRL_REG1_PD                       0x08
#define L3G4200D_REG_CTRL_REG1_XYZ_ENABLE               0x07

#define L3G4200D_REG_CTRL_REG4                     0x23
#define L3G4200D_REG_CTRL_REG4_FS_2000                  0x30

#define L3G4200D_REG_CTRL_REG5                     0x24
#define L3G4200D_REG_CTRL_REG5_FIFO_EN                  0x40

#define L3G4200D_REG_FIFO_CTL                      0x2e
#define L3G4200D_REG_FIFO_CTL_STREAM                    0x40

#define L3G4200D_REG_FIFO_SRC                      0x2f
#define L3G4200D_REG_FIFO_SRC_ENTRIES_MASK              0x1f
#define L3G4200D_REG_FIFO_SRC_EMPTY                     0x20
#define L3G4200D_REG_FIFO_SRC_OVERRUN                   0x40

#define L3G4200D_REG_XL                            0x28

// this bit is ORd into the register to enable auto-increment mode
#define L3G4200D_REG_AUTO_INCREMENT		           0x80

// L3G4200D Gyroscope scaling
// running at 2000 DPS full range, 16 bit signed data, datasheet 
// specifies 70 mdps per bit
#define L3G4200D_GYRO_SCALE_R_S (DEG_TO_RAD * 70.0f * 0.001f)

// constructor
AP_InertialSensor_L3G4200D::AP_InertialSensor_L3G4200D() :
    AP_InertialSensor(),
    _accel_filter_x(800, 10),
    _accel_filter_y(800, 10),
    _accel_filter_z(800, 10),
    _gyro_filter_x(800, 10),
    _gyro_filter_y(800, 10),
    _gyro_filter_z(800, 10)
{}

uint16_t AP_InertialSensor_L3G4200D::_init_sensor( Sample_rate sample_rate ) 
{

    switch (sample_rate) {
    case RATE_50HZ:
        _default_filter_hz = 10;
        _sample_period_usec = (1000*1000) / 50;
        _gyro_samples_needed = 16;
        break;
    case RATE_100HZ:
        _default_filter_hz = 20;
        _sample_period_usec = (1000*1000) / 100;
        _gyro_samples_needed = 8;
        break;
    case RATE_200HZ:
    default:
        _default_filter_hz = 20;
        _sample_period_usec = (1000*1000) / 200;
        _gyro_samples_needed = 4;
        break;
    }

    // get pointer to i2c bus semaphore
    AP_HAL::Semaphore* i2c_sem = hal.i2c->get_semaphore();

    // take i2c bus sempahore
    if (!i2c_sem->take(HAL_SEMAPHORE_BLOCK_FOREVER))
        return false;

    // Init the accelerometer
    uint8_t data = 0;
    hal.i2c->readRegister(ADXL345_ACCELEROMETER_ADDRESS, ADXL345_ACCELEROMETER_ADXLREG_DEVID, &data);
    if (data != ADXL345_ACCELEROMETER_XL345_DEVID) {
        hal.scheduler->panic(PSTR("AP_InertialSensor_L3G4200D: could not find ADXL345 accelerometer sensor"));
    }
    hal.i2c->writeRegister(ADXL345_ACCELEROMETER_ADDRESS, ADXL345_ACCELEROMETER_ADXLREG_POWER_CTL, 0x00);
    hal.scheduler->delay(5);
    hal.i2c->writeRegister(ADXL345_ACCELEROMETER_ADDRESS, ADXL345_ACCELEROMETER_ADXLREG_POWER_CTL, 0xff);
    hal.scheduler->delay(5);
    // Measure mode:
    hal.i2c->writeRegister(ADXL345_ACCELEROMETER_ADDRESS, ADXL345_ACCELEROMETER_ADXLREG_POWER_CTL, 0x08);
    hal.scheduler->delay(5);

    // Full resolution, 8g:
    // Caution, this must agree with ADXL345_ACCELEROMETER_SCALE_1G
    // In full resoution mode, the scale factor need not change
    hal.i2c->writeRegister(ADXL345_ACCELEROMETER_ADDRESS, ADXL345_ACCELEROMETER_ADXLREG_DATA_FORMAT, 0x08);
    hal.scheduler->delay(5);

    // Normal power, 800Hz Output Data Rate, 400Hz bandwidth:
    hal.i2c->writeRegister(ADXL345_ACCELEROMETER_ADDRESS, ADXL345_ACCELEROMETER_ADXLREG_BW_RATE, 0x0d);
    hal.scheduler->delay(5);

    // enable FIFO in stream mode. This will allow us to read the accelerometers much less frequently
    hal.i2c->writeRegister(ADXL345_ACCELEROMETER_ADDRESS, 
                           ADXL345_ACCELEROMETER_ADXLREG_FIFO_CTL, 
                           ADXL345_ACCELEROMETER_ADXLREG_FIFO_CTL_STREAM);

    // Init the Gyro
    // Expect to read the right 'WHO_AM_I' value
    hal.i2c->readRegister(L3G4200D_I2C_ADDRESS, L3G4200D_REG_WHO_AM_I, &data);
    if (data != L3G4200D_REG_WHO_AM_I_VALUE)
        hal.scheduler->panic(PSTR("AP_InertialSensor_L3G4200D: could not find L3G4200D gyro sensor"));

    // setup for 800Hz sampling with 110Hz filter
    hal.i2c->writeRegister(L3G4200D_I2C_ADDRESS, 
                           L3G4200D_REG_CTRL_REG1, 
                           L3G4200D_REG_CTRL_REG1_DRBW_800_110 |
                           L3G4200D_REG_CTRL_REG1_PD |
                           L3G4200D_REG_CTRL_REG1_XYZ_ENABLE);
    hal.scheduler->delay(1);

    hal.i2c->writeRegister(L3G4200D_I2C_ADDRESS, 
                           L3G4200D_REG_CTRL_REG1, 
                           L3G4200D_REG_CTRL_REG1_DRBW_800_110 |
                           L3G4200D_REG_CTRL_REG1_PD |
                           L3G4200D_REG_CTRL_REG1_XYZ_ENABLE);
    hal.scheduler->delay(1);

    hal.i2c->writeRegister(L3G4200D_I2C_ADDRESS, 
                           L3G4200D_REG_CTRL_REG1, 
                           L3G4200D_REG_CTRL_REG1_DRBW_800_110 |
                           L3G4200D_REG_CTRL_REG1_PD |
                           L3G4200D_REG_CTRL_REG1_XYZ_ENABLE);
    hal.scheduler->delay(1);

    // setup for 2000 degrees/sec full range
    hal.i2c->writeRegister(L3G4200D_I2C_ADDRESS, 
                           L3G4200D_REG_CTRL_REG4, 
                           L3G4200D_REG_CTRL_REG4_FS_2000);
    hal.scheduler->delay(1);

    // enable FIFO
    hal.i2c->writeRegister(L3G4200D_I2C_ADDRESS, 
                           L3G4200D_REG_CTRL_REG5, 
                           L3G4200D_REG_CTRL_REG5_FIFO_EN);
    hal.scheduler->delay(1);

    // enable FIFO in stream mode. This will allow us to read the gyros much less frequently
    hal.i2c->writeRegister(L3G4200D_I2C_ADDRESS,
                           L3G4200D_REG_FIFO_CTL,
                           L3G4200D_REG_FIFO_CTL_STREAM);
    hal.scheduler->delay(1);
                           

    // Set up the filter desired
    _set_filter_frequency(_mpu6000_filter);

    // give back i2c semaphore
    i2c_sem->give();

    // start the timer process to read samples
    hal.scheduler->register_timer_process(AP_HAL_MEMBERPROC(&AP_InertialSensor_L3G4200D::_accumulate));

    return AP_PRODUCT_ID_L3G4200D;
}

/*
  set the filter frequency
 */
void AP_InertialSensor_L3G4200D::_set_filter_frequency(uint8_t filter_hz)
{
    if (filter_hz == 0)
        filter_hz = _default_filter_hz;

    _accel_filter_x.set_cutoff_frequency(800, filter_hz);
    _accel_filter_y.set_cutoff_frequency(800, filter_hz);
    _accel_filter_z.set_cutoff_frequency(800, filter_hz);
    _gyro_filter_x.set_cutoff_frequency(800, filter_hz);
    _gyro_filter_y.set_cutoff_frequency(800, filter_hz);
    _gyro_filter_z.set_cutoff_frequency(800, filter_hz);
}

/*================ AP_INERTIALSENSOR PUBLIC INTERFACE ==================== */

bool AP_InertialSensor_L3G4200D::update(void) 
{
    if (!wait_for_sample(1000)) {
        return false;
    }
    Vector3f accel_scale = _accel_scale.get();

    _previous_accel = _accel;

    hal.scheduler->suspend_timer_procs();
    _accel = _accel_filtered;
    _gyro = _gyro_filtered;
    _gyro_samples_available = 0;
    hal.scheduler->resume_timer_procs();

    // add offsets and rotation
    _accel.rotate(_board_orientation);

    // Adjust for chip scaling to get m/s/s
    _accel *= ADXL345_ACCELEROMETER_SCALE_M_S;

    // Now the calibration scale factor
    _accel.x *= accel_scale.x;
    _accel.y *= accel_scale.y;
    _accel.z *= accel_scale.z;
    _accel   -= _accel_offset;

    _gyro.rotate(_board_orientation);

    // Adjust for chip scaling to get radians/sec
    _gyro *= L3G4200D_GYRO_SCALE_R_S;
    _gyro -= _gyro_offset;

    if (_last_filter_hz != _mpu6000_filter) {
        _set_filter_frequency(_mpu6000_filter);
        _last_filter_hz = _mpu6000_filter;
    }

    return true;
}

float AP_InertialSensor_L3G4200D::get_delta_time(void) 
{
    return _sample_period_usec * 1.0e-6f;
}

float AP_InertialSensor_L3G4200D::get_gyro_drift_rate(void) 
{
    // 0.5 degrees/second/minute (a guess)
    return ToRad(0.5/60);
}

// Accumulate values from accels and gyros
void AP_InertialSensor_L3G4200D::_accumulate(void)
{
    // get pointer to i2c bus semaphore
    AP_HAL::Semaphore* i2c_sem = hal.i2c->get_semaphore();

    // take i2c bus sempahore
    if (!i2c_sem->take_nonblocking())
        return;

    // Read accelerometer FIFO to find out how many samples are available
    uint8_t num_samples_available;
    uint8_t fifo_status = 0;
    hal.i2c->readRegister(ADXL345_ACCELEROMETER_ADDRESS,
                          ADXL345_ACCELEROMETER_ADXLREG_FIFO_STATUS,
                          &fifo_status);
    num_samples_available = fifo_status & 0x3F;

    // read the samples and apply the filter
    for (uint8_t i=0; i<num_samples_available; i++) {
        int16_t buffer[3];
        if (hal.i2c->readRegisters(ADXL345_ACCELEROMETER_ADDRESS, 
                                   ADXL345_ACCELEROMETER_ADXLREG_DATAX0, sizeof(buffer), (uint8_t *)buffer) == 0) {
            _accel_filtered = Vector3f(_accel_filter_x.apply(buffer[0]),
                                       _accel_filter_y.apply(-buffer[1]),
                                       _accel_filter_z.apply(-buffer[2]));
        }
    }

    // Read gyro FIFO status
    fifo_status = 0;
    hal.i2c->readRegister(L3G4200D_I2C_ADDRESS,
                          L3G4200D_REG_FIFO_SRC,
                          &fifo_status);
    if (fifo_status & L3G4200D_REG_FIFO_SRC_OVERRUN) {
        // FIFO is full
        num_samples_available = 32;
    } else if (fifo_status & L3G4200D_REG_FIFO_SRC_EMPTY) {
        // FIFO is empty
        num_samples_available = 0;
    } else {
        // FIFO is partly full
        num_samples_available = fifo_status & L3G4200D_REG_FIFO_SRC_ENTRIES_MASK;
    }

    if (num_samples_available > 0) {
        // read all the entries in one go, using AUTO_INCREMENT. This saves a lot of time on I2C setup
        int16_t buffer[num_samples_available][3];
        if (hal.i2c->readRegisters(L3G4200D_I2C_ADDRESS, L3G4200D_REG_XL | L3G4200D_REG_AUTO_INCREMENT, 
                                   sizeof(buffer), (uint8_t *)&buffer[0][0]) == 0) {
            for (uint8_t i=0; i<num_samples_available; i++) {
                _gyro_filtered = Vector3f(_gyro_filter_x.apply(buffer[i][0]), 
                                          _gyro_filter_y.apply(-buffer[i][1]), 
                                          _gyro_filter_z.apply(-buffer[i][2]));
                _gyro_samples_available++;
            }
        }
    }

    // give back i2c semaphore
    i2c_sem->give();
}

bool AP_InertialSensor_L3G4200D::sample_available(void)
{
    return (_gyro_samples_available >= _gyro_samples_needed);
}

bool AP_InertialSensor_L3G4200D::wait_for_sample(uint16_t timeout_ms)
{
    if (sample_available()) {
        _last_sample_time = hal.scheduler->micros();
        return true;
    }
    uint32_t start = hal.scheduler->millis();
    while ((hal.scheduler->millis() - start) < timeout_ms) {
        hal.scheduler->delay_microseconds(100);
        _accumulate();
        if (sample_available()) {
            _last_sample_time = hal.scheduler->micros();
            return true;
        }
    }
    return false;
}

#endif // CONFIG_HAL_BOARD