main.c

#include "ADXL345.h"
#include "address_map_arm.h"
#include "HardwareInit.h"
#include <math.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <time.h>
#include <sys/time.h>

#define DURATION 1000

// =============== INITIALIZE VALUE ==================
int fd;						                        //
void *LW_virtual;                                   //
volatile int *I2C0_ptr;    	                        //
volatile int *SYSMGR_ptr;                           //
int16_t XYZ[3];                                     //
int16_t mg_per_lsb = 4;                             //
// ============= END INITIALIZE VALUE ================

// ============= INITIALIZE PERIPHERAL ===============
int xyz[3];                                         //
uint8_t devid;                                      //    
volatile unsigned int *JP1_ptr;                     //    
volatile unsigned int *KEY_ptr;                     //
// ============= END INITIALIZE PERIPHERAL ===========

// =============== INITIALIZE FUNCTION ===============
double findPeakGroundAcceleration(int *xyz);        //
long getCurrTime();                                 //
// ============= END INITIALIZE FUNCTION =============

int main(void){

    // Init All the Hardware
    initHardward();

    // ================= MAP PERIPHERAL ==================
    JP1_ptr = (unsigned int*)(LW_virtual + JP1_BASE);   //
    *(JP1_ptr + 1) = 0x0000000F;                        //
    KEY_ptr = (unsigned int*)(LW_virtual + KEY_BASE);   //
    int buttonValue = *KEY_ptr;                         //
    int prevoiusButton = *KEY_ptr;                      //
    bool measure = false;                               //
    // ================= END PERIPHERAL ==================

    if (devid == 0xE5)
    {
        // Initialize accelerometer chip
        ADXL345_Init();

        long previousTime = getCurrTime();

        // MAIN LOOP
        // Keep running while the third button is not pressed
        while(buttonValue != 4)
        {
            buttonValue = *KEY_ptr;

            // ==== If button value change ==========
            if(prevoiusButton != buttonValue){     //
                if(buttonValue == 2) {             //
                    measure = false;               //
                }                                  //
                if(buttonValue == 1) {             //
                    measure = true;                //
                }                                  //
                prevoiusButton = buttonValue;      //
            }                                      //
            // === End If button value change =======

            // If measure is true and 2 second have pass
            if(measure && (getCurrTime() - previousTime > DURATION)){
                
                readAcceleration();
                double pga = findPeakGroundAcceleration(&xyz[0]);

                // Output to Hex and LEDR
                printf("PGA=%f m/s^2\n", pga);
                *JP1_ptr = pga;
                
                // Reset previousTime
                previousTime = getCurrTime();
                
            }
        }
    } 
    else 
    {
        printf("Incorrect device ID\n");
    }
	
	// Clean up
    close(fd);
    return 0;
}

//Find the Peak Ground Acceleration (PGA)
//by taking the square root of the sum of the squares of the X, Y, and Z values.
double findPeakGroundAcceleration(int *xyz) {
    double PGA;

    // Convert from mg to m/s^2
    double x = (xyz[0]) * (9.81/1000);
    double y = (xyz[1]) * (9.81/1000);
    double z = (xyz[2]-981) * (9.81/1000);
    
    //Find the Peak Ground Acceleration (PGA) 
    //by taking the square root of the sum of the squares of the X, Y, and Z values.
    PGA = sqrt((x*x) + (y*y) + (z*z));

    return PGA;
}

// Return a Long of  Current Time
long getCurrTime() {
    struct timeval tv;
    gettimeofday(&tv, NULL);
    return (tv.tv_sec * 1000) + (tv.tv_usec / 1000);
}

// Read Acceleration from ADXL345 
void readAcceleration(){
    ADXL345_XYZ_Read(XYZ);
    xyz[0] = XYZ[0]*mg_per_lsb;
    xyz[1] = XYZ[1]*mg_per_lsb;
    xyz[2] = XYZ[2]*mg_per_lsb;
}