Accelerometer LIS3LV02DL controlled by a dsPIC, I2C communication

This post describe the basic data acquisition of an accelerometer LIS3LV02DL over I2C bus using a dsPIC30F3012.
This tri-axial accelerometer has a 12 or 16 bit digital output and can be interfaced using SPI or I2C communication.
The circuit employed is a very simple one, The dsPIC is connected to the accelerometer LIS3LV02 via I2C using the B7 and B6 pines. The dsPIC reads the data and send the results in ascii format to the PC using the bluetooth module KC21.

Sampling rate of the sensor: 640Hz
Program sampling rate: 100Hz
Communication: I2C and Bluetooth



The program was made using the CCS compiler.

/////////////////////////////////////////////////////////////////////////////
// 01/OCT/2010, Chiba, Japan.
//Coder: Rigo
//Compiler: CCS
//Description: Program to read data from an accelerometer sensor using the I2C bus
//
//////////////////////////////////////////////////////
#include  "30f3012.h"                                //DEVICE
#FUSES HS2_PLL8//The xtal freq is divided by 2 and multiplied by 8 (maximum using 20MHz xtal)
#FUSES NOWDT // NO Watch Dog Timer
#FUSES PR_PLL //Primary Oscillator
#FUSES NOCKSFSM //Clock Switching is disabled, fail Safe clock monitor is disabled
#FUSES NOPROTECT //Code not protected from reading
#FUSES NOWRT //Program memory not write protected
#use delay(clock=80000000)// 20MHz/2*8=80MHz=80000000
#use rs232(baud=115200, xmit=PIN_B6, rcv=PIN_B7)            //To transmite result over Bluetooth
#use i2c(MASTER,SDA=PIN_C14,SCL=PIN_C13, fast=400)            // i2c define(For ACC)
//********************************
#define LED    PIN_D0
//LIS3LV02DL_register_define-----------------------
#define WRITE        0x3A   
#define READ         0x3B   
#define REG1         0x20
#define REG2         0x21
#define OUTX_L       0x28
#define OUTX_H       0x29
#define OUTY_L       0x2A
#define OUTY_H       0x2B
#define OUTZ_L       0x2C
#define OUTZ_H       0x2D
//=========================================================
int read_acc(int address_out);                //reading
long acc_change(int data_H,int data_L);       //change
float32 convert_into_g(int16 data);           //Converts into gravity values
//=========================================================
/*********** main **************/
////////////////////////////////////
void main()
{   
setup_adc_ports(NO_ANALOGS);                   //all digital I/O
int16 x_acc,  y_acc,  z_acc;                   //x,y,z-data_16bit
//Enabling the accelerometer 
i2c_start();                            //Sends a start command to the device
i2c_write(WRITE);                       //Sends a single byte preparing the device to receive data
i2c_write(REG1);                        //Indicate the device's addres to be modified   
i2c_write(0xE7);                        //11100111 = C7-->Turn on device activating all the axis, 640Hz sampling rate
i2c_stop();                             //Stop  I2C transmission
i2c_start();               //Start I2C communication
i2c_write(WRITE);          //Sends command to write data
i2c_write(REG2);           //Address the control register 2
i2c_write(0x40);           //01000001 --> 2g, no update between readings,12bits right justified
i2c_stop();                //Close trasmmision
/********* MAIN PROGRAM*************/
while(1)
{
output_high(LED);           
x_acc = read_acc(OUTX_L);    //Read data for the x axis
y_acc = read_acc(OUTY_L);    //Read data for the y axis
z_acc = read_acc(OUTZ_L);    //Read data for the z axis
//********************************
float X_out;             //Define floating variables for results in G units
float Y_out;
float Z_out;
X_out=convert_into_g(x_acc);            //Converts binary value into g
Y_out=convert_into_g(y_acc);
Z_out=convert_into_g(z_acc);
printf("  X  %g ", X_out); //display    //send results over RS232
printf("  Y  %g ", Y_out); //display
printf("  Z  %g \n \r", Z_out); //display
delay_ms(10);                           //delay for sampling 100Hz
output_low(LED);   
}
}   
//**************************************************************************************************
int16 read_acc(int address_out)
{
int DL=0x00, DH=0x00;    
int16 out = 0;
i2c_start();                //Start communication
i2c_write(WRITE);           //prepare the device to receive data
i2c_write(address_out|0x80);  //address register, autoincrement of address
i2c_start();                //
i2c_write(READ);            //Prepares the device to be read
DL=i2c_read();              //Read data LSB
DH=i2c_read(0);             //Read data MSB
i2c_stop();                //Stop  condition
//concatenating result    
out=DL|((DH&0x0F)<<8);     //Join the LSB and the MSB 
return(out);              //Returns the result
}
//**************************************************************************************************
float32 convert_into_g(int16 data)
{
float output;
output=(float)data;       //Converts integer data into float
if (data>=2048)         //check if the result is indicating a negative value
{
output=(output/1024)-4;  //Converts into g
}
if (data<2048)          //if the result indicates a positive value
{
output=output/1024;   //converts into g
}
return(output);               //Returns the result
}
//*****************************************************************

Output displayed in the computer using a simple and free serial terminal.
My very very ugly implementation using breadboard