[General] Weird problem with Intel Edison and IMU MPU-9150

[freddyp007]

Hi guys,

So I am trying to get measurements from the MPU-9150 sensor from Invensense using the Intel Edison. I am able to communicate with the sensor and the values seem sensible.

But after a specific number of cycles, I measure only a zero from all data registers. This error is repeatable: When I try to read the Accelerometer and Gyro data(6 data registers), the data stream stops exactly at 84 cycles. If I try to read jus the Accelerometer values, it stops at double the no. of cycles i.e. 168. I sense some data is overflowing, but couldn't figure out yet.

Looking for your reply and Thanks!

Cheers,

Frederic

Code:

MPU9150.h

//Self Test registers R/W

#define SELF_TEST_X  0x0D

#define SELF_TEST_Y  0x0E

#define SELF_TEST_Z  0x0F

#define SELF_TEST_A  0x0A

//Configuration Registers

#define SMPRT_DIV    0x19 //Sample Rate Divider

#define CONFIG       0x1A //FSYNC & DLPF config

#define GYRO_CONFIG  0x1B //Self-Test & Scale select

#define ACCEL_CONFIG 0x1C //Self-Test & Scale select

//Interrupt Registers

#define INT_ENABLE   0x38

#define INT_STATUS   0x3A

//Accelerometer Measurement Registers

#define ACCEL_XOUT_H 0x3B

#define ACCEL_XOUT_L 0x3C

#define ACCEL_YOUT_H 0x3D

#define ACCEL_YOUT_L 0x3E

#define ACCEL_ZOUT_H 0x3F

#define ACCEL_ZOUT_L 0x40

//Temperature Measurement Registers

//Temperature in degrees C = (TEMP_OUT Register Value as a signed quantity)/340 + 35

#define TEMP_OUT_H   0x41

#define TEMP_OUT_L   0x42

//Gyroscope Measurement Registers

#define GYRO_XOUT_H  0x43

#define GYRO_XOUT_L  0x44

#define GYRO_YOUT_H  0x45

#define GYRO_YOUT_L  0x46

#define GYRO_ZOUT_H  0x47

#define GYRO_ZOUT_L  0x48

//Power Management Registers

#define PWR_MGMT_1   0x6B

#define PWR_MGMT_2   0x6C

//Device i.d. Register

#define WHO_AM_I     0x75

/*

R1 - 0x69

R2 - 0x68

*/

#define MPU_ADDR     0x68

//Reset the Registers and Power

#define PWR_RESET    0x80

#define DEVICE_ON    0x00

//Accelerometer Scale

#define ACCEL_2G     0x00

#define ACCEL_4G     0x08

#define ACCEL_8G     0x10

#define ACCEL_16G    0x18

//Gyroscope Scale

#define GYRO_250     0x00

#define GYRO_500     0x08

#define GYRO_1000    0x10

#define GYRO_2000    0x18

#define SAMPLE_RATE  0x00

#define DLPF_CFG     0x01

MPU9150.c

#include <stdio.h>

#include <stdlib.h>

#include <signal.h>

#include "mraa.h"

#include "MPU9150.h"

void MPU9150_I2C_Init(void);

void MPU9150_I2C_Config(void);

void MPU9150_I2C_Write(uint8_t address, uint8_t value);

void MPU9150_I2C_Read(uint8_t address, uint8_t *value);

int16_t MPU9150_Get_Measurement(uint8_t addrL, uint8_t addrH);

void sig_handler(int signum);

sig_atomic_t volatile isrunning = 1;

//Acceleometer Measurement Storage Variables

int16_t Accel_X = 0;

int16_t Accel_Y = 0;

int16_t Accel_Z = 0;

//Gyroscope Measurement Storage Variables

int16_t Gyro_X = 0;

int16_t Gyro_Y = 0;

int16_t Gyro_Z = 0;

//Temperature Measurement Storage Variable

float Temperature = 0;

//Variable to Store LOW and HIGH Register values

uint8_t Measurement_L = 0;

uint8_t Measurement_H = 0;

int main(int argc, char **argv)

{

    printf("--------------------------------------------------\n");

    printf("------------------eGlove Project------------------\n");

    printf("--------------------------------------------------\n");

    sleep(1); //1s delay

    

    signal(SIGINT, &sig_handler);

    usleep(1000); //1ms delay

    

    MPU9150_I2C_Init();

    sleep(1); //1s delay

    MPU9150_I2C_Config();    

    sleep(1); //1s delay

    

    while(isrunning)

    {

        //Get Accelerometer Measurements

        Accel_X = MPU9150_Get_Measurement(ACCEL_XOUT_L, ACCEL_XOUT_H);

    Accel_Y = MPU9150_Get_Measurement(ACCEL_YOUT_L, ACCEL_YOUT_H);

    Accel_Z = MPU9150_Get_Measurement(ACCEL_ZOUT_L, ACCEL_ZOUT_H);

        //Get Gyroscope Measurements

    Gyro_X = MPU9150_Get_Measurement(GYRO_XOUT_L, GYRO_XOUT_H);

    Gyro_Y = MPU9150_Get_Measurement(GYRO_YOUT_L, GYRO_YOUT_H);

    Gyro_Z = MPU9150_Get_Measurement(GYRO_ZOUT_L, GYRO_ZOUT_H);

        

        //Print Accelerometer Values

        printf("Accelerometer:\n X:%d\n Y:%d\n Z:%d\n ", Accel_X, Accel_Y, Accel_Z);

        

        //Print Gyroscope Values

    printf("Gyroscope:\n X:%d\n Y:%d\n Z:%d\n ", Gyro_X, Gyro_Y,Gyro_Z);

        

        //Sample Readings every second

        sleep(1); //1s delay

    }

    return MRAA_SUCCESS;

}

void MPU9150_I2C_Init(void)

{

    mraa_init();

    mraa_i2c_context mpu9150_i2c;

    mpu9150_i2c = mraa_i2c_init(1);

    

  if (mpu9150_i2c == NULL) 

    {

        printf("MPU9150 I2C initialization failed, exit...\n");

        exit(1);

    }

    

    printf("MPU9150 I2C initialized successfully\n");

    

    mraa_i2c_address(mpu9150_i2c, MPU_ADDR);

    printf("MPU9150 I2C Address set to 0x%x\n", MPU_ADDR);

}

void MPU9150_I2C_Config(void)

{

    mraa_i2c_context mpu9150_i2c;

    mpu9150_i2c = mraa_i2c_init(1);

    

    //Reset all the Registers

  mraa_i2c_address(mpu9150_i2c, MPU_ADDR);

    MPU9150_I2C_Write(PWR_MGMT_1, PWR_RESET);

    printf("MPU9150 Reset\n");

    sleep(1); //1s delay

    

    mraa_i2c_address(mpu9150_i2c, MPU_ADDR);

     MPU9150_I2C_Write(PWR_MGMT_1, DEVICE_ON);

    printf("MPU9150 Switched ON\n");

    sleep(1); //1s delay

    

    mraa_i2c_address(mpu9150_i2c, MPU_ADDR);

  uint8_t data = mraa_i2c_read_byte_data(mpu9150_i2c, WHO_AM_I);

  printf("Who am I: 0x%x\n", data);

    sleep(1); //1s delay

    

     MPU9150_I2C_Write(SMPRT_DIV, SAMPLE_RATE);

    

     MPU9150_I2C_Write(CONFIG, DLPF_CFG);

     //Set the Gyroscope Scale to 250°/s

     MPU9150_I2C_Write(GYRO_CONFIG, GYRO_500);

    

    //Set the Accelerometer Scale to 2G

     MPU9150_I2C_Write(ACCEL_CONFIG, ACCEL_2G);

    

    printf("Initialization Complete: All Systems are GO!!!\n");

}

void MPU9150_I2C_Write(uint8_t address, uint8_t value)

{

    mraa_i2c_context mpu9150_i2c;

    mpu9150_i2c = mraa_i2c_init(1);

    

    //Set MPU Device Address

    mraa_i2c_address(mpu9150_i2c, MPU_ADDR);

    

    //Write Command and Data

    mraa_i2c_write_byte_data(mpu9150_i2c, value, address);

}

void MPU9150_I2C_Read(uint8_t address, uint8_t *value)

{

    mraa_i2c_context mpu9150_i2c;

    mpu9150_i2c = mraa_i2c_init(1);

    

    //Set ALS Device Address

    mraa_i2c_address(mpu9150_i2c, MPU_ADDR);

    

    //Write Command and Read Data

    *value = mraa_i2c_read_byte_data(mpu9150_i2c, address);

}

int16_t MPU9150_Get_Measurement(uint8_t addrL, uint8_t addrH)

{    

    //Read & Store the Lower Byte

    MPU9150_I2C_Read(addrL, &Measurement_L);

    

    //Read & Store the Higher Byte

    MPU9150_I2C_Read(addrH, &Measurement_H);

  

  return (int16_t)((Measurement_H << 8) + Measurement_L);

}

//Signal Handler

void sig_handler(int signum)

{

    if(signum == SIGINT)

    {

        isrunning = 0;

    }

}

Console Screenshot:



Reference:

MPU-9150 Product Specification: http://43zrtwysvxb2gf29r5o0athu.wpe...ontent/uploads/2015/02/MPU-9150-Datasheet.pdf

MPU-9150 Register Map: http://43zrtwysvxb2gf29r5o0athu.wpe...ent/uploads/2015/02/MPU-9150-Register-Map.pdf