Merge pull request #727 from drf5n/oversampling

temperature.cpp: Actually use OVERSAMPLENR in the oversampling calculation.

Marlin/Configuration.h

                                   // is more then PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define PID_INTEGRAL_DRIVE_MAX 255  //limit for the integral term
   #define K1 0.95 //smoothing factor within the PID
-  #define PID_dT ((16.0 * 8.0)/(F_CPU / 64.0 / 256.0)) //sampling period of the temperature routine
+  #define PID_dT ((OVERSAMPLENR * 8.0)/(F_CPU / 64.0 / 256.0)) //sampling period of the temperature routine
 
 // If you are using a preconfigured hotend then you can use one of the value sets by uncommenting it
 // Ultimaker

Marlin/temperature.cpp

 //      break;
   }
     
-  if(temp_count >= 16) // 8 ms * 16 = 128ms.
+  if(temp_count >= OVERSAMPLENR) // 8 * 16 * 1/(16000000/64/256)  = 131ms.
   {
     if (!temp_meas_ready) //Only update the raw values if they have been read. Else we could be updating them during reading.
     {