Clarify the mV/°C scale

Author: thinkyhead

Marlin/src/module/temperature.cpp

@@ -2142,8 +2142,10 @@ void Temperature::task() {
   UNUSED(ms);
 }
 
-#define TEMP_AD595(RAW)  ((RAW) * (HAL_ADC_VREF) * 100.0 / float(HAL_ADC_RANGE) / (OVERSAMPLENR) * (TEMP_SENSOR_AD595_GAIN) + TEMP_SENSOR_AD595_OFFSET)
-#define TEMP_AD8495(RAW) ((RAW) * (HAL_ADC_VREF) * 2 * 100.0 / float(HAL_ADC_RANGE) / (OVERSAMPLENR) * (TEMP_SENSOR_AD8495_GAIN) + TEMP_SENSOR_AD8495_OFFSET)
+// For a 5V input the AD595 returns a value scaled with 10mV per °C.
+#define TEMP_AD595(RAW)  ((RAW) * (HAL_ADC_VREF) * (1000.0f / 10.0f) / float(HAL_ADC_RANGE) / (OVERSAMPLENR) * (TEMP_SENSOR_AD595_GAIN) + TEMP_SENSOR_AD595_OFFSET)
+// For a 5V input the AD8495 returns a value scaled with 5mV per °C.
+#define TEMP_AD8495(RAW) ((RAW) * (HAL_ADC_VREF) * (1000.0f /  5.0f) / float(HAL_ADC_RANGE) / (OVERSAMPLENR) * (TEMP_SENSOR_AD8495_GAIN) + TEMP_SENSOR_AD8495_OFFSET)
 
 /**
  * Bisect search for the range of the 'raw' value, then interpolate