File content as of revision 2:516dd8a72972:

#include "mbed.h"
#include "LSM9DS1.h"
#define PI 3.14159
// Earth's magnetic field varies by location. Add or subtract
// a declination to get a more accurate heading. Calculate
// your's here:
// http://www.ngdc.noaa.gov/geomag-web/#declination
#define DECLINATION -4.94 // Declination (degrees) in Atlanta,GA.

//Serial pc(USBTX, USBRX);
RawSerial  pc(USBTX, USBRX);
RawSerial  dev(p28,p27); //tx, rx
DigitalOut myled(LED1);
DigitalOut led2(LED2);
DigitalOut led4(LED4);
// Calculate pitch, roll, and heading.
// Pitch/roll calculations taken from this app note:
// http://cache.freescale.com/files/sensors/doc/app_note/AN3461.pdf?fpsp=1
// Heading calculations taken from this app note:
// http://www51.honeywell.com/aero/common/documents/myaerospacecatalog-documents/Defense_Brochures-documents/Magnetic__Literature_Application_notes-documents/AN203_Compass_Heading_Using_Magnetometers.pdf
void printAttitude(float ax, float ay, float az, float mx, float my, float mz)
{
    float roll = atan2(ay, az);
    float pitch = atan2(-ax, sqrt(ay * ay + az * az));
// touchy trig stuff to use arctan to get compass heading (scale is 0..360)
    mx = -mx;
    float heading;
    if (my == 0.0)
        heading = (mx < 0.0) ? 180.0 : 0.0;
    else
        heading = atan2(mx, my)*360.0/(2.0*PI);
    //pc.printf("heading atan=%f \n\r",heading);
    heading -= DECLINATION; //correct for geo location
    if(heading>180.0) heading = heading - 360.0;
    else if(heading<-180.0) heading = 360.0 + heading;
    else if(heading<0.0) heading = 360.0  + heading;


    // Convert everything from radians to degrees:
    //heading *= 180.0 / PI;
    pitch *= 180.0 / PI;
    roll  *= 180.0 / PI;

    //~pc.printf("Pitch: %f,    Roll: %f degress\n\r",pitch,roll);
    //~pc.printf("Magnetic Heading: %f degress\n\r",heading);
}

/*
void dev_recv()
{
    led2 = !led2;
    while(dev.readable()) {
        pc.putc(dev.getc());
    }
}

void pc_recv()
{
    led4 = !led4;
    while(pc.readable()) {
        dev.putc(pc.getc());
    }
}*/

int main()
{
    //IMU setup
    LSM9DS1 IMU(p9, p10, 0xd6, 0x3c);
    IMU.begin();
    if (!IMU.begin()) {
        pc.printf("Failed to communicate with LSM9DS1.\n");
    }
    IMU.calibrate(1);
    IMU.calibrateMag(0);
    
    //bluetooth setup
    pc.baud(9600);
    dev.baud(9600);

    /*pc.attach(&pc_recv, Serial::RxIrq);
    dev.attach(&dev_recv, Serial::RxIrq);*/
    
    while(1) {
    
        while(!IMU.magAvailable(X_AXIS));
        IMU.readMag();
        while(!IMU.accelAvailable());
        IMU.readAccel();
        while(!IMU.gyroAvailable());
        IMU.readGyro();
        pc.puts("        X axis    Y axis    Z axis\n\r");
        dev.puts("        X axis    Y axis    Z axis\n\r");
        //pc.printf("gyro:  %9f %9f %9f in deg/s\n\r", IMU.calcGyro(IMU.gx), IMU.calcGyro(IMU.gy), IMU.calcGyro(IMU.gz));
        //pc.printf("accel: %9f %9f %9f in Gs\n\r", IMU.calcAccel(IMU.ax), IMU.calcAccel(IMU.ay), IMU.calcAccel(IMU.az));
        //pc.printf("mag:   %9f %9f %9f in gauss\n\r", IMU.calcMag(IMU.mx), IMU.calcMag(IMU.my), IMU.calcMag(IMU.mz));
        printAttitude(IMU.calcAccel(IMU.ax), IMU.calcAccel(IMU.ay), IMU.calcAccel(IMU.az), IMU.calcMag(IMU.mx),
                      IMU.calcMag(IMU.my), IMU.calcMag(IMU.mz));
        myled = 1;
        wait(0.5);
        myled = 0;
        wait(0.5);
        

        //uLCD.filled_circle(floor(128*oldtempX), floor(128*oldtempY), 6, 0x000000);    // erase old bubble

        //draw filled circle based on info from IMU
        //draw new bubble
        //uLCD.filled_circle(floor(128*tempX), floor(128*tempY), 6, 0xFFFFFF);
        
    }
}