File content as of revision 0:ce9707156696:

#include "mbed.h"
#include "ICM20948.hpp"
extern Serial pc1(USBTX,USBRX);
I2C  ICM20948_i2c(p9,p10); // I2C0_SDA, I2C0_SCL


ICM20948::ICM20948()
{
    ICM20948_i2c.frequency(400000);
    gyroBias[0] = 0;
    gyroBias[1] = 0;
    gyroBias[2] = 0;
}

ICM20948::~ICM20948() {}

void ICM20948::ICM_WriteByte(uint8_t ICM20948_reg, uint8_t ICM20948_data)
{
    char data_out[2];
    data_out[0]=ICM20948_reg;
    data_out[1]=ICM20948_data;
    ICM20948_i2c.write(ICM20948_slave_addr, data_out, 2, 0);
}

uint8_t ICM20948::ICM_ReadByte(uint8_t ICM20948_reg)
{
    char data_out[1], data_in[1];
    data_out[0] = ICM20948_reg;
    ICM20948_i2c.write(ICM20948_slave_addr, data_out, 1, 1);
    ICM20948_i2c.read(ICM20948_slave_addr, data_in, 1, 0);
    return (data_in[0]);
}

// Communication test: WHO_AM_I register reading
void ICM20948::whoAmI()
{
    uint8_t whoAmI = ICM_ReadByte(ICM20948_WHO_AM_I);   // Should return 0x68
    pc.printf("I AM ICM20948: 0x%x \r\n",whoAmI);

    if(whoAmI==0xea) {
        pc.printf("WHO_AM_I OK! ICM20948 is detected!\r\n");
    } else {
        pc.printf("WHO_AM_I FAILED! Could not connect to ICM20948 \r\nCheck the connections... \r\n");
    }

}

void ICM20948::powerOn()
{
    // USER_BANK_0 を使用
    ICM_WriteByte(ICM20948_REG_BANK_SEL, USER_BANK_0);
    ICM_WriteByte(ICM20948_PWR_MGMT_1, 0x01);
    // 一旦アクセル，ジャイロの電源を落して，
    //ICM_WriteOneByte(ICM20948_PWR_MGMT_2, (0x38 | 0x07));
    ICM_WriteByte(ICM20948_PWR_MGMT_2, (0x38 | 0x07));
    wait_ms(10);
    // からの再起動でリセット
    //ICM_WriteOneByte(ICM20948_PWR_MGMT_2, (0x00 | 0x00));
    ICM_WriteByte(ICM20948_PWR_MGMT_2, (0x00 | 0x00));
}

void ICM20948::init()
{
    powerOn();

    // USER_BANK_2 を使用
    ICM_WriteByte(ICM20948_REG_BANK_SEL, USER_BANK_2);

    // ジャイロのレンジとLPFの使用有無を設定
    //ICM_WriteOneByte(GYRO_CONFIG_1, (GYRO_RATE_250 | GYRO_LPF_230Hz));
    ICM_WriteByte(ICM20948_GYRO_CONFIG_1, (GYRO_RATE_250 | GYRO_LPF_17Hz));
    gRes = 250.0/32768.0 * 2.0 * 3.1415926 / 360.0; // 設定した Ndps / 32768.0
    // ジャイロのサンプリングレートを設定
    //ICM_WriteOneByte(ICM20948_GYRO_SMPLRT_DIV, GYRO_SMPLRT_100Hz);
    ICM_WriteByte(ICM20948_GYRO_SMPLRT_DIV, GYRO_SMPLRT_100Hz);

    // 加速度のレンジとLPFの使用有無を設定
    //ICM_WriteOneByte(ACCEL_CONFIG, (ACC_RATE_2g | ACC_LPF_136HZ));
    ICM_WriteByte(ICM20948_ACCEL_CONFIG, (ACC_RATE_2g | ACC_LPF_136HZ));
    aRes = 2.0/32768.0; // 選択した Ng / 32768.0
    // 加速度のサンプリングレートを設定
    //ICM_WriteOneByte(ICM20948_ACCEL_SMPLRT_DIV_2, ACC_SMPLRT_100Hz);
    ICM_WriteByte(ICM20948_ACCEL_SMPLRT_DIV_2, ACC_SMPLRT_100Hz);

    // USER_BANK_0 に戻す
    ICM_WriteByte(ICM20948_REG_BANK_SEL, USER_BANK_0);
    wait_ms(10);
    
    // ジャイロのキャリブレーション
    gyroCalib();
}

// ジャイロのキャリブレーション．100回の平均をとって引く
void ICM20948::gyroCalib(){
    pc.printf("Calibrating Gyro ... Wait for 5s\n\r");
    int16_t gxtmp, gytmp, gztmp;
    float gx, gy, gz;
    gx = 0.0; gy = 0.0; gz = 0.0;
    uint8_t LoByte, HiByte;
    for(int i = 0; i < 100; i++){
        LoByte = ICM_ReadByte(ICM20948_GYRO_XOUT_L); // read Gyrometer X_Low  value
        HiByte = ICM_ReadByte(ICM20948_GYRO_XOUT_H); // read Gyrometer X_High value
        gxtmp = ((HiByte<<8) | LoByte);
        gx += (float)(gxtmp) * gRes;
        
        LoByte = ICM_ReadByte(ICM20948_GYRO_YOUT_L);
        HiByte = ICM_ReadByte(ICM20948_GYRO_YOUT_H);
        gytmp = ((HiByte<<8) | LoByte);
        gy += (float)(gytmp) * gRes;
        
        LoByte = ICM_ReadByte(ICM20948_GYRO_ZOUT_L);
        HiByte = ICM_ReadByte(ICM20948_GYRO_ZOUT_H);
        gztmp = ((HiByte<<8) | LoByte);
        gz += (float)(gztmp) * gRes;
        //pc.printf("%d %f, %d %f, %d %f\n\r", gxtmp, gx, gytmp, gy, gztmp, gz);
        wait_ms(50);
    }
    
    gyroBias[0] = gx / 100.0;
    gyroBias[1] = gy / 100.0;
    gyroBias[2] = gz / 100.0;
    
    pc.printf("Gyro Bias: %f %f %f\n\r", gyroBias[0], gyroBias[1], gyroBias[2]);
}

void ICM20948::getAccGyro(float acc[3], float gyro[3]){
    int16_t ax, ay, az, gx, gy, gz;
    uint8_t LoByte, HiByte;
    
    LoByte = ICM_ReadByte(ICM20948_ACCEL_XOUT_L); // read Accelerometer X_Low  value
    HiByte = ICM_ReadByte(ICM20948_ACCEL_XOUT_H); // read Accelerometer X_High value
    ax = (HiByte<<8) | LoByte;
    acc[0] = ((float)(ax)) * aRes;
    
    LoByte = ICM_ReadByte(ICM20948_ACCEL_YOUT_L);
    HiByte = ICM_ReadByte(ICM20948_ACCEL_YOUT_H);
    ay = (HiByte<<8) | LoByte;
    acc[1] = ((float)(ay)) * aRes;
    
    LoByte = ICM_ReadByte(ICM20948_ACCEL_ZOUT_L);
    HiByte = ICM_ReadByte(ICM20948_ACCEL_ZOUT_H);
    az = (HiByte<<8) | LoByte;
    acc[2] = ((float)(az)) * aRes;
    
    LoByte = ICM_ReadByte(ICM20948_GYRO_XOUT_L); // read Gyrometer X_Low  value
    HiByte = ICM_ReadByte(ICM20948_GYRO_XOUT_H); // read Gyrometer X_High value
    gx = (HiByte<<8) | LoByte;
    gyro[0] = ((float)(gx)) * gRes - gyroBias[0];
    
    LoByte = ICM_ReadByte(ICM20948_GYRO_YOUT_L);
    HiByte = ICM_ReadByte(ICM20948_GYRO_YOUT_H);
    gy = (HiByte<<8) | LoByte;
    gyro[1] = ((float)(gy)) * gRes - gyroBias[1];
    
    LoByte = ICM_ReadByte(ICM20948_GYRO_ZOUT_L);
    HiByte = ICM_ReadByte(ICM20948_GYRO_ZOUT_H);
    gz = (HiByte<<8) | LoByte;
    gyro[2] = ((float)(gz)) * gRes - gyroBias[2];
    
}

int16_t ICM20948::getIMUTemp()
{
    uint8_t LoByte, HiByte;
    LoByte = ICM_ReadByte(ICM20948_TEMP_OUT_L); // read Accelerometer X_Low  value
    HiByte = ICM_ReadByte(ICM20948_TEMP_OUT_H); // read Accelerometer X_High value
    return ((HiByte<<8) | LoByte);
}