MPU9250 test with polling or ISR

Dependencies:   mbed



File content as of revision 0:31cc139b7d1e:

/* MPU9250 Basic Example Code
 by: Kris Winer
 date: April 1, 2014
 license: Beerware - Use this code however you'd like. If you 
 find it useful you can buy me a beer some time.
 Demonstrate basic MPU-9250 functionality including parameterizing the register addresses, initializing the sensor, 
 getting properly scaled accelerometer, gyroscope, and magnetometer data out. Added display functions to 
 allow display to on breadboard monitor. Addition of 9 DoF sensor fusion using open source Madgwick and 
 Mahony filter algorithms. Sketch runs on the 3.3 V 8 MHz Pro Mini and the Teensy 3.1.
 SDA and SCL should have external pull-up resistors (to 3.3V).
 10k resistors are on the EMSENSR-9250 breakout board.
 Hardware setup:
 MPU9250 Breakout --------- Arduino
 VDD ---------------------- 3.3V
 VDDI --------------------- 3.3V
 SDA ----------------------- A4
 SCL ----------------------- A5
 GND ---------------------- GND
 Note: The MPU9250 is an I2C sensor and uses the Arduino Wire library. 
 Because the sensor is not 5V tolerant, we are using a 3.3 V 8 MHz Pro Mini or a 3.3 V Teensy 3.1.
 We have disabled the internal pull-ups used by the Wire library in the Wire.h/twi.c utility file.
 We are also using the 400 kHz fast I2C mode by setting the TWI_FREQ  to 400000L /twi.h utility file.
//#include "ST_F401_84MHZ.h" 
//F401_init84 myinit(0);
#include "mbed.h"
#include "MPU9250.h"

float sum = 0;
uint32_t sumCount = 0;

   MPU9250 mpu9250;
   Timer t;

   Serial pc(USBTX, USBRX); // tx, rx

volatile bool newData = false;

InterruptIn isrPin(D12);   //k64 D12  dragon PD_0

void mpuisr() {
int main()

  //Set up I2C
  i2c.frequency(400000);  // use fast (400 kHz) I2C  
  pc.printf("CPU SystemCoreClock is %d Hz\r\n", SystemCoreClock);   
  // Read the WHO_AM_I register, this is a good test of communication
  uint8_t whoami = mpu9250.readByte(MPU9250_ADDRESS, WHO_AM_I_MPU9250);  // Read WHO_AM_I register for MPU-9250
  pc.printf("I AM 0x%x\n\r", whoami); pc.printf("I SHOULD BE 0x71\n\r");
  if (whoami == 0x71) // WHO_AM_I should always be 0x68
    pc.printf("MPU9250 is online...\n\r");

    mpu9250.resetMPU9250(); // Reset registers to default in preparation for device calibration
    mpu9250.calibrateMPU9250(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers  
    pc.printf("x gyro bias = %f\n\r", gyroBias[0]);
    pc.printf("y gyro bias = %f\n\r", gyroBias[1]);
    pc.printf("z gyro bias = %f\n\r", gyroBias[2]);
    pc.printf("x accel bias = %f\n\r", accelBias[0]);
    pc.printf("y accel bias = %f\n\r", accelBias[1]);
    pc.printf("z accel bias = %f\n\r", accelBias[2]);
    pc.printf("MPU9250 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature
    pc.printf("AK8963 initialized for active data mode....\n\r"); // Initialize device for active mode read of magnetometer
    pc.printf("Accelerometer full-scale range = %f  g\n\r", 2.0f*(float)(1<<Ascale));
    pc.printf("Gyroscope full-scale range = %f  deg/s\n\r", 250.0f*(float)(1<<Gscale));
    if(Mscale == 0) pc.printf("Magnetometer resolution = 14  bits\n\r");
    if(Mscale == 1) pc.printf("Magnetometer resolution = 16  bits\n\r");
    if(Mmode == 2) pc.printf("Magnetometer ODR = 8 Hz\n\r");
    if(Mmode == 6) pc.printf("Magnetometer ODR = 100 Hz\n\r");
    pc.printf("Could not connect to MPU9250: \n\r");
    pc.printf("%#x \n",  whoami);

    while(1) ; // Loop forever if communication doesn't happen

    mpu9250.getAres(); // Get accelerometer sensitivity
    mpu9250.getGres(); // Get gyro sensitivity
    mpu9250.getMres(); // Get magnetometer sensitivity
    pc.printf("Accelerometer sensitivity is %f LSB/g \n\r", 1.0f/aRes);
    pc.printf("Gyroscope sensitivity is %f LSB/deg/s \n\r", 1.0f/gRes);
    pc.printf("Magnetometer sensitivity is %f LSB/G \n\r", 1.0f/mRes);
    magbias[0] = +470.;  // User environmental x-axis correction in milliGauss, should be automatically calculated
    magbias[1] = +120.;  // User environmental x-axis correction in milliGauss
    magbias[2] = +125.;  // User environmental x-axis correction in milliGauss

 while(1) {
    static int readycnt=0;
  // If intPin goes high, all data registers have new data
  if(newData) {
    mpu9250.readByte(MPU9250_ADDRESS, INT_STATUS);  //? need this with ISR
    if(mpu9250.readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) {  // On interrupt, check if data ready interrupt
    mpu9250.readAccelData(accelCount);  // Read the x/y/z adc values   
    // Now we'll calculate the accleration value into actual g's
    ax = (float)accelCount[0]*aRes - accelBias[0];  // get actual g value, this depends on scale being set
    ay = (float)accelCount[1]*aRes - accelBias[1];   
    az = (float)accelCount[2]*aRes - accelBias[2];  
    mpu9250.readGyroData(gyroCount);  // Read the x/y/z adc values
    // Calculate the gyro value into actual degrees per second
    gx = (float)gyroCount[0]*gRes - gyroBias[0];  // get actual gyro value, this depends on scale being set
    gy = (float)gyroCount[1]*gRes - gyroBias[1];  
    gz = (float)gyroCount[2]*gRes - gyroBias[2];   
    mpu9250.readMagData(magCount);  // Read the x/y/z adc values   
    // Calculate the magnetometer values in milliGauss
    // Include factory calibration per data sheet and user environmental corrections
    mx = (float)magCount[0]*mRes*magCalibration[0] - magbias[0];  // get actual magnetometer value, this depends on scale being set
    my = (float)magCount[1]*mRes*magCalibration[1] - magbias[1];  
    mz = (float)magCount[2]*mRes*magCalibration[2] - magbias[2];   
    Now = t.read_us();
    deltat = (float)((Now - lastUpdate)/1000000.0f) ; // set integration time by time elapsed since last filter update
    lastUpdate = Now;
    sum += deltat;
//    if(lastUpdate - firstUpdate > 10000000.0f) {
//     beta = 0.04;  // decrease filter gain after stabilized
//     zeta = 0.015; // increasey bias drift gain after stabilized
 //   }
   // Pass gyro rate as rad/s
   uint32_t us = t.read_us();
  mpu9250.MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f,  my,  mx, mz);
   us = t.read_us()-us;
 // mpu9250.MahonyQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz);

    // Serial print and/or display at 0.5 s rate independent of data rates
    delt_t = t.read_ms() - count;
    if (delt_t > 500) { // update LCD once per half-second independent of read rate
        pc.printf("readycnt %d us %d\n",readycnt,us);
    pc.printf("ax = %f", 1000*ax); 
    pc.printf(" ay = %f", 1000*ay); 
    pc.printf(" az = %f  mg\n\r", 1000*az); 

    pc.printf("gx = %f", gx); 
    pc.printf(" gy = %f", gy); 
    pc.printf(" gz = %f  deg/s\n\r", gz); 
    pc.printf("gx = %f", mx); 
    pc.printf(" gy = %f", my); 
    pc.printf(" gz = %f  mG\n\r", mz); 
    tempCount = mpu9250.readTempData();  // Read the adc values
    temperature = ((float) tempCount) / 333.87f + 21.0f; // Temperature in degrees Centigrade
    pc.printf("temperature = %f  C\n\r", temperature); 
    pc.printf("q0 = %f\n\r", q[0]);
    pc.printf("q1 = %f\n\r", q[1]);
    pc.printf("q2 = %f\n\r", q[2]);
    pc.printf("q3 = %f\n\r", q[3]);      

  // Define output variables from updated quaternion---these are Tait-Bryan angles, commonly used in aircraft orientation.
  // In this coordinate system, the positive z-axis is down toward Earth. 
  // Yaw is the angle between Sensor x-axis and Earth magnetic North (or true North if corrected for local declination, looking down on the sensor positive yaw is counterclockwise.
  // Pitch is angle between sensor x-axis and Earth ground plane, toward the Earth is positive, up toward the sky is negative.
  // Roll is angle between sensor y-axis and Earth ground plane, y-axis up is positive roll.
  // These arise from the definition of the homogeneous rotation matrix constructed from quaternions.
  // Tait-Bryan angles as well as Euler angles are non-commutative; that is, the get the correct orientation the rotations must be
  // applied in the correct order which for this configuration is yaw, pitch, and then roll.
  // For more see which has additional links.
    yaw   = atan2(2.0f * (q[1] * q[2] + q[0] * q[3]), q[0] * q[0] + q[1] * q[1] - q[2] * q[2] - q[3] * q[3]);   
    pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2]));
    roll  = atan2(2.0f * (q[0] * q[1] + q[2] * q[3]), q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]);
    pitch *= 180.0f / PI;
    yaw   *= 180.0f / PI; 
    yaw   -= 13.8f; // Declination at Danville, California is 13 degrees 48 minutes and 47 seconds on 2014-04-04
    roll  *= 180.0f / PI;

    pc.printf("Yaw, Pitch, Roll: %f %f %f\n\r", yaw, pitch, roll);
    pc.printf("average rate = %f\n\r", (float) sumCount/sum);
    myled= !myled;
    count = t.read_ms(); 
    sum = 0;
    sumCount = 0;