ICM-42686原始值换算

1.初始化ICM-42686陀螺仪为1000dps和加速计为2g

/*
 * GYRO_CONFIG0:Gyro Full scale and sampling rate config
 * GYRO_FS_SEL[bit5-7],GYRO_ODR[bit0-3],page 58 of 105
 * GYRO_FS_SEL:
    0x00:+-4000dps(default); 0x02:+-2000dps; 0x40:+-1000dps;0x60:+-500dps
 * GYRO_ODR:
    0x00:Reserved; 0x01:32KHz; 0x02:16KHz; 0x03:8KHz; 0x04:4KHz;
    0x05:2KHz; 0x06:1KHz(default); 0x07:200Hz; 0x08:100Hz;
 */
regmap_write(dev->regmap, GYRO_CONFIG0,  0x43);    //+-1000dps//8KHz

/*
* ACCEL_CONFIG0
* ACCEL_FS_SEL[bit5-7] and ACCEL_ODR[bit0-3]) address=0x50,value default 0x06
* ACCEL_FS_SEL: 000: +-32g; 001:+-16g; 010:+-8g; 011:+-4g; 100:+-2g;
* ACCEL_ODR:0001:32KHz; 0010:16KHz; 0011: 8KHz; 0100: 4KHz;0101: 2KHz;0110: 1KHz;
*    0111: 200Hz; 1000: 1000Hz; 1001:50Hz; 1010:25Hz
*/
regmap_write(dev->regmap, ACCEL_CONFIG0,  0x83);/* full scale: +-2g,accel sampling rate: 8KHz*/

2.用量程和位宽换算IMU的值

/* accelerometer */
struct imu_acc
{
    float ax;   /* x axes */
    float ay;   /* y axes */
    float az;   /* z axes */
};

/* gyroscope */
struct imu_gry
{
    float gx;   /* x axes */
    float gy;   /* y axes */
    float gz;   /* z axes */
};

/*
 * 相邻两个8位组成16位数据，然后转换为浮点数
 * @data_h ：高8位
 * @data_l ：低8位
 */
static float imu_data_to_float( const unsigned char data_h, const unsigned char data_l)
{
    union
    {
        short data_short;
        unsigned short data_ushort;
    } us2f;

    us2f.data_ushort = (((unsigned short)data_h) << 8) | data_l;

    return (float)us2f.data_short;
}

/*
 * IMU数据解析
 * @pimu : imu 采集到的原始数据， pimu[0]为高8位，pimu[1]为低8位；
 */
void imu_data_resolving(unsigned char * pimu, struct imu_acc * acc, struct imu_gry * gry)
{
    acc->ax = (imu_data_to_float(pimu[0], pimu[1])) * 4 / 65536.0;
    acc->ay = (imu_data_to_float(pimu[2], pimu[3])) * 4 / 65536.0;
    acc->az = (imu_data_to_float(pimu[4], pimu[5])) * 4 / 65536.0;

    gry->gx = (imu_data_to_float(pimu[6], pimu[7])) * 2000 / 65536.0;
    gry->gy = (imu_data_to_float(pimu[8], pimu[9])) * 2000 / 65536.0;
    gry->gz = (imu_data_to_float(pimu[10], pimu[11])) * 2000 / 65536.0;
}