     /* wait for a new second to start, and capture millis() in start */
     do	{
         now = RTC->TR & (RTC_TR_ST | RTC_TR_SU);
-        start = millis();
+        start = micros();
         } while (second == now);
 
     /* update our second of interest */

        delay(500);
        }

    return CalibNew;
    }

uint32_t
MeasureMillisPerRtcSecond(
    void
    )
    {

    LMIC_reset();

    // set clock rate error to 0.1%
    //LMIC_setClockError(1 * MAX_CLOCK_ERROR / 1000);

    // do the network-specific setup prior to join.
    setupForNetwork(false);
