File content as of revision 0:51c8d005e429:

#include "mbed.h"
#include "FastAnalogIn.h"

Serial pc(USBTX, USBRX); //Configuración de los pines deñ serial
DigitalInOut SDA(PTB3); //Pin para el SDA
DigitalOut    SCL(PTB2);//Pin para el SCL

typedef signed short i16;
const unsigned char PI =3.14159265;

const unsigned char ADDRESS_READ  = 0b11010001;    //address of GY-87 for read
const unsigned char ADDRESS_WRITE = 0b11010000;    //addres of GY-87 for write
const unsigned char ACCEL_CONFIGURATION  = 0x00;// // Full scale range = +/-2g

const unsigned char accel_reg_dir = 0x1C;  //Address acelerometer register
const unsigned char accel_data =    0x3B; 
double lsb=16384.0;   //sensibilidad del acelerometro

double angleX,angleY,angleZ,forceX,forceY,forceZ,x; //Variables para el ángulo y fuerza
i16 ACCELX;
i16 ACCELY;
i16 ACCELZ;

unsigned char data_accel_xyz[6];

void IIC_init (void)
{
   SCL=0;
   SDA=0;
   SDA.output();//conf SDA salida
   asm("nop");
   asm("nop");
   asm("nop");
   asm("nop");
}

void IIC_start (void)
{
    SDA=1;
    SCL=1;
    asm("nop");
    asm("nop");
    SDA=0;
    asm("nop"); //esperar 1u con nop's   
    SCL=0;
    asm("nop");
    asm("nop");
}

void IIC_stop (void)
{
    SCL=1;
    //esperar TSU.STO STOP Condition Setup Time con nop's 600 ns min
    asm("nop");
    SDA=1;
    //esperar tBUF, Bus Free Time Between STOP and START Condition 1.3us min 
    asm("nop");
    asm("nop");
    SCL=0;
    SDA=0;
}

unsigned char IIC_read_byte (void)
{
    unsigned char temp;
    unsigned char cont;
    cont=8;
    SDA.input();//configurar SDA como entrada
do
{
    temp<<=1;
    SCL=1;
    if (SDA==1) temp |= 0x01;
    asm("nop");
    asm("nop");
    SCL=0;
    asm("nop");
    asm("nop");
}while (--cont);
    SDA.output();//configurar SDA como salida
    return temp;
} 

void IIC_ACK_output (unsigned char ACK_output)
{
    if (ACK_output==0) SDA=0;
    else SDA=1;
    asm("nop");
    SCL=1;
    asm("nop"); 
    asm("nop");
    asm("nop");
    SCL=0;
    SDA=0; 
}

void error()
{
   while(true){}
}

void IIC_send_byte (unsigned char byte)
{
    unsigned char data;
    unsigned char i=8;
    data=byte;
    do{
         if (data&0x80)
         {
             SDA=1;
         }
         else 
         {
             SDA=0;
         }
         SCL=1;
         asm("nop");
         asm("nop");
         asm("nop");
         SCL=0;
         asm("nop");
         asm("nop");
         asm("nop");
         data<<=1;
    }while (--i);
    SDA=0;
}

unsigned char IIC_ACK_inp (void)
{
unsigned char temp;
   SDA.input();//SDA entrada
   SCL=1;
   if (SDA==0) temp=0;
   else temp=1;
   SCL=0;
   SDA.output();//SDA salida
   return temp;    
}
void IIC_byte_write(const unsigned char direccion, unsigned char dato)
{
    IIC_start();
    IIC_send_byte(ADDRESS_WRITE);
    if (IIC_ACK_inp()==1)
    error();
    IIC_send_byte((char)direccion);
    if (IIC_ACK_inp()==1) error();
    IIC_send_byte(dato);
    if (IIC_ACK_inp()==1) error();
    IIC_stop();
}

void IIC_sequential_read(const unsigned int direccion, unsigned char num_bytes)
{
    unsigned char restador=num_bytes;
    unsigned char iterador = 0;
    IIC_start();
    IIC_send_byte(ADDRESS_WRITE);
    if (IIC_ACK_inp()==1) error();
    IIC_send_byte((char)direccion);
    if (IIC_ACK_inp()==1) error();
    IIC_start();
    IIC_send_byte(ADDRESS_READ);
    if (IIC_ACK_inp()==1) error();
    
    do{
        data_accel_xyz[iterador++]=IIC_read_byte();
        IIC_ACK_output(0);
    }while(--restador);
    IIC_ACK_output(1);
    IIC_stop();
}

void Data_converter() //Función para pasar los datos de 8 bits a las variables de 16 bits
{
    ACCELX = data_accel_xyz[0]<<8 | data_accel_xyz[1];
    ACCELY = data_accel_xyz[2]<<8;
    ACCELY|= data_accel_xyz[3];
    ACCELZ = data_accel_xyz[4]<<8;
    ACCELZ|= data_accel_xyz[5];   
}

void ANGULOS(){ //Función para sacar los ángulos correspondientes de cada eje
        angleX=atan((double)ACCELX/(sqrt((double)(ACCELZ*ACCELZ+ACCELY*ACCELY))))*180/PI;
        angleY=atan((double)ACCELY/(sqrt((double)(ACCELZ*ACCELZ+ACCELX*ACCELX))))*180/PI;
        angleZ=atan((double)ACCELZ/(sqrt((double)(ACCELX*ACCELX+ACCELY*ACCELY))))*180/PI;
    }
void FORCE(){ //Función para sacar la fuerza respecto a cada eje
           x=(double)ACCELX;
           forceX=x/lsb;
           forceY=(double)ACCELY/(16384.0);
           forceZ=(double)ACCELZ/(16384.0);
           
    }

int main() {
    IIC_init();
    //configuracion del registro acelerometro 
    IIC_byte_write(0x6B,0b00000000);
    IIC_init();
    IIC_byte_write(accel_reg_dir,ACCEL_CONFIGURATION );
    while(true) {
       IIC_init();
       IIC_sequential_read(accel_data,6);
       Data_converter();
       ANGULOS();
       FORCE();
       pc.printf("Angle: X:%f Y:%f Z:%f \n",angleX,angleY,angleZ);
       pc.printf("\r");
       pc.printf("Ac(g): X:%f Y:%f Z:%f \n",forceX,forceY,forceZ);
       pc.printf("\r");
       
    }
}