File content as of revision 5:131450b16ce3:

#include "LSM9DS1.h"

LSM9DS1::LSM9DS1(PinName sda, PinName scl, uint8_t xgAddr, uint8_t mAddr) : i2c(sda, scl)
{
    // xgAddress and mAddress will store the 7-bit I2C address, if using I2C.
    xgAddress = xgAddr;
    mAddress = mAddr;
}

uint16_t LSM9DS1::begin(gyro_scale gScl, accel_scale aScl, mag_scale mScl, 
                        gyro_odr gODR, accel_odr aODR, mag_odr mODR)
{
    // Store the given scales in class variables. These scale variables
    // are used throughout to calculate the actual g's, DPS,and Gs's.
    gScale = gScl;
    aScale = aScl;
    mScale = mScl;
    
    // Once we have the scale values, we can calculate the resolution
    // of each sensor. That's what these functions are for. One for each sensor
    calcgRes(); // Calculate DPS / ADC tick, stored in gRes variable
    calcmRes(); // Calculate Gs / ADC tick, stored in mRes variable
    calcaRes(); // Calculate g / ADC tick, stored in aRes variable
    
    
    // To verify communication, we can read from the WHO_AM_I register of
    // each device. Store those in a variable so we can return them.
    // The start of the addresses we want to read from
    char cmd[2] = {
        WHO_AM_I_XG,
        0
    };

    // Write the address we are going to read from and don't end the transaction
    i2c.write(xgAddress, cmd, 1, true);
    // Read in all the 8 bits of data
    i2c.read(xgAddress, cmd+1, 1);
    uint8_t xgTest = cmd[1];                    // Read the accel/gyro WHO_AM_I
    
    // Reset to the address of the mag who am i
    cmd[1] = WHO_AM_I_M;
    // Write the address we are going to read from and don't end the transaction
    i2c.write(mAddress, cmd, 1, true);
    // Read in all the 8 bits of data
    i2c.read(mAddress, cmd+1, 1);
    uint8_t mTest = cmd[1];      // Read the mag WHO_AM_I
    
    // Gyro initialization stuff:
    initGyro(); // This will "turn on" the gyro. Setting up interrupts, etc.
    setGyroODR(gODR); // Set the gyro output data rate and bandwidth.
    setGyroScale(gScale); // Set the gyro range
    
    // Accelerometer initialization stuff:
    initAccel(); // "Turn on" all axes of the accel. Set up interrupts, etc.
    setAccelODR(aODR); // Set the accel data rate.
    setAccelScale(aScale); // Set the accel range.
    
    // Magnetometer initialization stuff:
    initMag(); // "Turn on" all axes of the mag. Set up interrupts, etc.
    setMagODR(mODR); // Set the magnetometer output data rate.
    setMagScale(mScale); // Set the magnetometer's range.
    
    // Once everything is initialized, return the WHO_AM_I registers we read:
    return (xgTest << 8) | mTest;
}

void LSM9DS1::initGyro()
{
    char cmd[4] = {
        CTRL_REG1_G,
        gScale | G_ODR_119_BW_14,
        0,          // Default data out and int out
        0           // Default power mode and high pass settings
    };

    // Write the data to the gyro control registers
    i2c.write(xgAddress, cmd, 4);
}

void LSM9DS1::initAccel()
{
    char cmd[4] = {
        CTRL_REG5_XL,
        0x38,       // Enable all axis and don't decimate data in out Registers
        (A_ODR_119 << 5) | (aScale << 3) | (A_BW_AUTO_SCALE),   // 119 Hz ODR, set scale, and auto BW
        0           // Default resolution mode and filtering settings
    };

    // Write the data to the accel control registers
    i2c.write(xgAddress, cmd, 4);
}

void LSM9DS1::initMag()
{   
    char cmd[4] = {
        CTRL_REG1_M,
        0x10,       // Default data rate, xy axes mode, and temp comp
        mScale << 5, // Set mag scale
        0           // Enable I2C, write only SPI, not LP mode, Continuous conversion mode
    };

    // Write the data to the mag control registers
    i2c.write(mAddress, cmd, 4);
}

void LSM9DS1::readAccel()
{
    // The data we are going to read from the accel
    char data[6];

    // The start of the addresses we want to read from
    char subAddress = OUT_X_L_XL;

    // Write the address we are going to read from and don't end the transaction
    i2c.write(xgAddress, &subAddress, 1, true);
    // Read in all 8 bit registers containing the axes data
    i2c.read(xgAddress, data, 6);

    // Reassemble the data and convert to g
    ax_raw = data[0] | (data[1] << 8);
    ay_raw = data[2] | (data[3] << 8);
    az_raw = data[4] | (data[5] << 8);
    ax = ax_raw * aRes;
    ay = ay_raw * aRes;
    az = az_raw * aRes;
}

void LSM9DS1::readMag()
{
    // The data we are going to read from the mag
    char data[6];

    // The start of the addresses we want to read from
    char subAddress = OUT_X_L_M;

    // Write the address we are going to read from and don't end the transaction
    i2c.write(mAddress, &subAddress, 1, true);
    // Read in all 8 bit registers containing the axes data
    i2c.read(mAddress, data, 6);

    // Reassemble the data and convert to degrees
    mx_raw = data[0] | (data[1] << 8);
    my_raw = data[2] | (data[3] << 8);
    mz_raw = data[4] | (data[5] << 8);
    mx = mx_raw * mRes;
    my = my_raw * mRes;
    mz = mz_raw * mRes;
}

void LSM9DS1::readTemp()
{
    // The data we are going to read from the temp
    char data[2];

    // The start of the addresses we want to read from
    char subAddress = OUT_TEMP_L;

    // Write the address we are going to read from and don't end the transaction
    i2c.write(xgAddress, &subAddress, 1, true);
    // Read in all 8 bit registers containing the axes data
    i2c.read(xgAddress, data, 2);

    // Temperature is a 12-bit signed integer   
    temperature_raw = data[0] | (data[1] << 8);

    temperature_c = (float)temperature_raw / 8.0 + 25;
    temperature_f = temperature_c * 1.8 + 32;
}


void LSM9DS1::readGyro()
{
    // The data we are going to read from the gyro
    char data[6];

    // The start of the addresses we want to read from
    char subAddress = OUT_X_L_G;

    // Write the address we are going to read from and don't end the transaction
    i2c.write(xgAddress, &subAddress, 1, true);
    // Read in all 8 bit registers containing the axes data
    i2c.read(xgAddress, data, 6);

    // Reassemble the data and convert to degrees/sec
    gx_raw = data[0] | (data[1] << 8);
    gy_raw = data[2] | (data[3] << 8);
    gz_raw = data[4] | (data[5] << 8);
    gx = gx_raw * gRes;
    gy = gy_raw * gRes;
    gz = gz_raw * gRes;
}

void LSM9DS1::setGyroScale(gyro_scale gScl)
{
    // The start of the addresses we want to read from
    char cmd[2] = {
        CTRL_REG1_G,
        0
    };

    // Write the address we are going to read from and don't end the transaction
    i2c.write(xgAddress, cmd, 1, true);
    // Read in all the 8 bits of data
    i2c.read(xgAddress, cmd+1, 1);

    // Then mask out the gyro scale bits:
    cmd[1] &= 0xFF^(0x3 << 3);
    // Then shift in our new scale bits:
    cmd[1] |= gScl << 3;

    // Write the gyroscale out to the gyro
    i2c.write(xgAddress, cmd, 2);
    
    // We've updated the sensor, but we also need to update our class variables
    // First update gScale:
    gScale = gScl;
    // Then calculate a new gRes, which relies on gScale being set correctly:
    calcgRes();
}

void LSM9DS1::setAccelScale(accel_scale aScl)
{
    // The start of the addresses we want to read from
    char cmd[2] = {
        CTRL_REG6_XL,
        0
    };

    // Write the address we are going to read from and don't end the transaction
    i2c.write(xgAddress, cmd, 1, true);
    // Read in all the 8 bits of data
    i2c.read(xgAddress, cmd+1, 1);

    // Then mask out the accel scale bits:
    cmd[1] &= 0xFF^(0x3 << 3);
    // Then shift in our new scale bits:
    cmd[1] |= aScl << 3;

    // Write the accelscale out to the accel
    i2c.write(xgAddress, cmd, 2);
    
    // We've updated the sensor, but we also need to update our class variables
    // First update aScale:
    aScale = aScl;
    // Then calculate a new aRes, which relies on aScale being set correctly:
    calcaRes();
}

void LSM9DS1::setMagScale(mag_scale mScl)
{
    // The start of the addresses we want to read from
    char cmd[2] = {
        CTRL_REG2_M,
        0
    };

    // Write the address we are going to read from and don't end the transaction
    i2c.write(mAddress, cmd, 1, true);
    // Read in all the 8 bits of data
    i2c.read(mAddress, cmd+1, 1);

    // Then mask out the mag scale bits:
    cmd[1] &= 0xFF^(0x3 << 5);
    // Then shift in our new scale bits:
    cmd[1] |= mScl << 5;

    // Write the magscale out to the mag
    i2c.write(mAddress, cmd, 2);
    
    // We've updated the sensor, but we also need to update our class variables
    // First update mScale:
    mScale = mScl;
    // Then calculate a new mRes, which relies on mScale being set correctly:
    calcmRes();
}

void LSM9DS1::setGyroODR(gyro_odr gRate)
{
    // The start of the addresses we want to read from
    char cmd[2] = {
        CTRL_REG1_G,
        0
    };

    // Write the address we are going to read from and don't end the transaction
    i2c.write(xgAddress, cmd, 1, true);
    // Read in all the 8 bits of data
    i2c.read(xgAddress, cmd+1, 1);

    // Then mask out the gyro odr bits:
    cmd[1] &= (0x3 << 3);
    // Then shift in our new odr bits:
    cmd[1] |= gRate;

    // Write the gyroodr out to the gyro
    i2c.write(xgAddress, cmd, 2);
}

void LSM9DS1::setAccelODR(accel_odr aRate)
{
    // The start of the addresses we want to read from
    char cmd[2] = {
        CTRL_REG6_XL,
        0
    };

    // Write the address we are going to read from and don't end the transaction
    i2c.write(xgAddress, cmd, 1, true);
    // Read in all the 8 bits of data
    i2c.read(xgAddress, cmd+1, 1);

    // Then mask out the accel odr bits:
    cmd[1] &= 0xFF^(0x7 << 5);
    // Then shift in our new odr bits:
    cmd[1] |= aRate << 5;

    // Write the accelodr out to the accel
    i2c.write(xgAddress, cmd, 2);
}

void LSM9DS1::setMagODR(mag_odr mRate)
{
    // The start of the addresses we want to read from
    char cmd[2] = {
        CTRL_REG1_M,
        0
    };

    // Write the address we are going to read from and don't end the transaction
    i2c.write(mAddress, cmd, 1, true);
    // Read in all the 8 bits of data
    i2c.read(mAddress, cmd+1, 1);

    // Then mask out the mag odr bits:
    cmd[1] &= 0xFF^(0x7 << 2);
    // Then shift in our new odr bits:
    cmd[1] |= mRate << 2;

    // Write the magodr out to the mag
    i2c.write(mAddress, cmd, 2);
}

void LSM9DS1::calcgRes()
{
    // Possible gyro scales (and their register bit settings) are:
    // 245 DPS (00), 500 DPS (01), 2000 DPS (10).
    switch (gScale)
    {
        case G_SCALE_245DPS:
            gRes = 245.0 / 32768.0;
            break;
        case G_SCALE_500DPS:
            gRes = 500.0 / 32768.0;
            break;
        case G_SCALE_2000DPS:
            gRes = 2000.0 / 32768.0;
            break;
    }
}

void LSM9DS1::calcaRes()
{
    // Possible accelerometer scales (and their register bit settings) are:
    // 2 g (000), 4g (001), 6g (010) 8g (011), 16g (100).
    switch (aScale)
    {
        case A_SCALE_2G:
            aRes = 2.0 / 32768.0;
            break;
        case A_SCALE_4G:
            aRes = 4.0 / 32768.0;
            break;
        case A_SCALE_8G:
            aRes = 8.0 / 32768.0;
            break;
        case A_SCALE_16G:
            aRes = 16.0 / 32768.0;
            break;
    }
}

void LSM9DS1::calcmRes()
{
    // Possible magnetometer scales (and their register bit settings) are:
    // 2 Gs (00), 4 Gs (01), 8 Gs (10) 12 Gs (11). 
    switch (mScale)
    {
        case M_SCALE_4GS:
            mRes = 4.0 / 32768.0;
            break;
        case M_SCALE_8GS:
            mRes = 8.0 / 32768.0;
            break;
        case M_SCALE_12GS:
            mRes = 12.0 / 32768.0;
            break;
        case M_SCALE_16GS:
            mRes = 16.0 / 32768.0;
            break;
    }
}