 
     draw_template();
     fill_data(temp_in, temp_out, humid_in, humid_out, pressure);
+    print_time_string(3 /* 4th row */);
 
     
     LOG("delay "); LOGLN(sleep_time);

|Out:-20.5°C  100% RH|
|Pressure:    Err hPa|
|Pressure: 1013.9 hPa|
|12:34:56  12.12.2017|
+--------------------+
 */


LiquidCrystal_I2C lcd(0x27, 20, 4);  // set the LCD address to 0x27 for a 20 chars and 4 line display


// Real-time clock
DS3231 rtc;

// Delay
const int32_t sleep_time = 1000; // 1000ms

// Error value
const int32_t err_val = 200000;


/* returns time-date string via param from rtc.
 * rtc should be at least 21 bytes long.
 */
void print_time_string(unsigned row)
{
    bool tmp1 = false;
    bool tmp2 = false;

    char str[21];
    byte ret;

    /*
     * 01234567890123456789
     * 17:34:59  31.12.2017
     */

    // hour
    ret = rtc.getHour(tmp1, tmp2);
    str[0] = ret / 10;
    str[1] = ret % 10;

    str[2] = ':';

    // minute
    ret = rtc.getMinute();
    str[3] = ret / 10;
    str[4] = ret % 10;

    str[5] = ':';

    // second
    ret = rtc.getSecond();
    str[6] = ret / 10;
    str[7] = ret % 10;

    str[8] = ' ';
    str[9] = ' ';

    // day
    ret = rtc.getDate();
    str[10] = ret / 10;
    str[11] = ret % 10;

    str[12] = '.';

    // month
    ret = rtc.getMonth(tmp1);
    str[13] = ret / 10;
    str[14] = ret % 10;

    str[15] = '.';

    // year - only last two digits
    ret = rtc.getYear();
    str[16] = '2';
    str[17] = '0';
    str[18] = ret / 10;
    str[19] = ret % 10;

    // end of string
    str[20] = '\0';

    lcd.setCursor(0, row);
    lcd.print(str);
}

void setup ()
{
