File content as of revision 3:10f685ebc7ef:

#include "mbed.h"

Serial pc(USBTX,USBRX);
I2C accelero(p28, p27);
SPI afficheurSPI(p5, p6, p7);
DigitalOut afficheurSelect(p8);

 
const char reg[] = {0x0d};
const int device = 0x3A;
char data[1];
int radtodeg = 57;

int16_t normal[3] = {0,0,1};



int printDecimalNumber(int i){
    char chiffres[4];
    if (i > 9999) {
        afficheurSelect = 0;
        afficheurSPI.write(0x76);
        afficheurSPI.write('e');
        afficheurSPI.write('e');
        afficheurSPI.write('e');
        afficheurSPI.write('e');
        wait(0.001);
        afficheurSelect = 1;
    }
    else {
        // Convert number to char list
        chiffres[0] = i / 1000;
        chiffres[1] = (i - int(chiffres[0]) * 1000) / 100;
        chiffres[2] = (i - int(chiffres[0]) * 1000 - int(chiffres[1]) * 100) / 10;
        chiffres[3] = i - int(chiffres[0]) * 1000 - int(chiffres[1]) * 100 - int(chiffres[2]) * 10;
        
        afficheurSelect= 0;
        afficheurSPI.write(0x76);
        afficheurSPI.write(0x77);
        afficheurSPI.write(0b00000010);
        for (int x = 0; x < 4; x++) {
            afficheurSPI.write(chiffres[x]);
        }
        wait(0.001);
        afficheurSelect = 1;
    }
    return 0;
}

int main() {
    
    afficheurSPI.frequency(100000);
    
    accelero.write(device,reg,1,true);
    accelero.read(device,data,1);
        
    pc.printf("Result : %d \r\n", data[0]);
    printDecimalNumber((int) data[0]);
    
    // Set 2g max
    char XYZ_DATA_CFG[2] = {0x0e, 0};
    char value[1]; 
    accelero.read(device, XYZ_DATA_CFG, 1, true);
    accelero.write(device, value, 1);
    value[0] = value[0] & 0xFC;
    
    XYZ_DATA_CFG[1] = value[0];
    accelero.write(device, XYZ_DATA_CFG, 2);
    
    // Activate accelerometer
    char ctrlReg1[2] = {0x2a, 0};
    accelero.write(device, ctrlReg1, 1, true);
    accelero.read(device, value, 1);
    value[0] = value[0] | 0x1;
    
    ctrlReg1[1] = value[0];
    accelero.write(device, ctrlReg1, 2);
    
    char XYZ_Data = 0x01;
    char data[6];
    int16_t x, y, z;
    int16_t buffer;
    
    int buffersize = 128;
    int shiftsize = 7;
    int mean[buffersize];
    int angle;
    
    int iteration = 0;
    while(1) {
        accelero.write(device, &XYZ_Data, 1, true);
        accelero.read(device, data, 6);
        
        ((char*) &buffer)[0]= data[1];    //LSB
        ((char*) &buffer)[1]= data[0];    //MSB
        x = buffer >> 4;
        ((char*) &buffer)[0]= data[3];    //LSB
        ((char*) &buffer)[1]= data[2];    //MSB
        y = buffer >> 4;
        ((char*) &buffer)[0]= data[5];    //LSB
        ((char*) &buffer)[1]= data[4];    //MSB
        z = buffer >> 4;
        
        z = std::abs(z);
        if (z > 1024)
            z = 1024;
        
        int theta = std::acos((double) z / (double) 1024) * radtodeg * 100;
        mean[iteration % buffersize] = theta >> shiftsize;
        
        if (iteration % 64 == 0){
            angle = 0;
            for (int i = 0; i < buffersize; i++){
                angle += mean[i];
            }
            printDecimalNumber(angle);
        }
        wait(0.0006);
        iteration++;
    }
}