File content as of revision 3:68f55e42c85f:

#include "mbed.h"
#include "GYRO_DISCO_F429ZI.h"
#include "LCD_DISCO_F429ZI.h"
#include "stm32f429i_discovery_lcd.h"

GYRO_DISCO_F429ZI gyro;
LCD_DISCO_F429ZI lcd;

DigitalOut led1(LED1);

int main()
{
    float GyroBuffer[3];
    float zero_level[3] = {0, 0, 0};
    uint8_t buffer[100];
    lcd.Init();
    lcd.DisplayStringAt(10, 10, (uint8_t*)"Gyroscope_started", CENTER_MODE);
    uint8_t tmpreg = 0;
    GYRO_IO_Read(&tmpreg,L3GD20_CTRL_REG4_ADDR,1);
    switch(tmpreg & L3GD20_FULLSCALE_SELECTION)
    {
        case L3GD20_FULLSCALE_250:
            lcd.DisplayStringAt(20, 20, (uint8_t*)"250", CENTER_MODE);
        break;
    
        case L3GD20_FULLSCALE_500:
            lcd.DisplayStringAt(20, 20, (uint8_t*)"500", CENTER_MODE);
        break;
    
        case L3GD20_FULLSCALE_2000:
            lcd.DisplayStringAt(20, 20, (uint8_t*)"2000", CENTER_MODE);
        break;
  }
    GYRO_IO_Read(&tmpreg, L3GD20_CTRL_REG1_ADDR, 1);
    switch(tmpreg >> 6) {
        case 0:
            lcd.DisplayStringAt(20, 40, (uint8_t*)"95", CENTER_MODE);
            break;
        case 1:
            lcd.DisplayStringAt(20, 40, (uint8_t*)"190", CENTER_MODE);
            break;
        case 2:
            lcd.DisplayStringAt(20, 40, (uint8_t*)"380", CENTER_MODE);
            break;
        case 3:
            lcd.DisplayStringAt(20, 40, (uint8_t*)"760", CENTER_MODE);
            break;
    }

    for (int i = 0; i < 50; i++) {
        gyro.GetXYZ(GyroBuffer);
        zero_level[0] += GyroBuffer[0] / 17.5f;
        zero_level[1] += GyroBuffer[1] / 17.5f;
        zero_level[2] += GyroBuffer[2] / 17.5f;

        wait_ms(10);
    }
    for (int i = 0; i < 3; i++)
        zero_level[i] /= 50;
    
    float noise_level = 0.0;
    for (int i = 0; i < 50; i++) {
        gyro.GetXYZ(GyroBuffer);
        if ((GyroBuffer[0] / 17.5f - zero_level[0]) > noise_level) {
            noise_level = (GyroBuffer[0] / 17.5f - zero_level[0]);
        } 
        else if ((GyroBuffer[0] / 17.5f - zero_level[0]) < -noise_level) {
            noise_level = -(GyroBuffer[0] / 17.5f - zero_level[0]);
        }
        wait_ms(10);
    }
    sprintf((char*)buffer, "Noise = %.2f\n", noise_level);
    lcd.DisplayStringAt(20, 70, buffer, CENTER_MODE);
    float angle = 0.0, prev_value = 0.0;
    while(1) {
        // Read Gyroscope values
        wait(0.02);
        
        gyro.GetXYZ(GyroBuffer);
        float value = GyroBuffer[0] / 17.5f - zero_level[0];
        if (value >= noise_level || value <= -noise_level) {
            angle += (value + prev_value) / 2 * 0.0175 * 0.02f / 0.825;
        }
        prev_value = value;
        sprintf((char*)buffer, "Angle = %.3f\n", angle);
        lcd.DisplayStringAt(20, 100, buffer, CENTER_MODE);
        
    }
}