Serial output is affected while sampling temperature

When running the Temperature example, the output for the word
“Temperature:” was being corrupted when sampling the temperature.
Moved away from using sleep_mode and altering the restoration of the
registers.  Both changes were needed to fix the serial output issue.

Author: carledwards

utility/halTemperature.c

@@ -15,35 +15,31 @@
 
 /*****************************************************************************
 *****************************************************************************/
-static volatile uint8_t halAdcFinished;
 static int8_t halAdcOffset;
 
+static inline void sleep (void)
+{
+    asm volatile("sleep");
+}
+
 /*****************************************************************************
 *****************************************************************************/
 static inline int16_t HAL_AdcMeasure(void) {
-  set_sleep_mode(SLEEP_MODE_ADC);
   /* dummy cycle */
-  halAdcFinished = false;
   do
   {
-    sleep_mode();
-    /* sleep, wake up by ADC IRQ */
-    /* check here for ADC IRQ because sleep mode could wake up from * another source too */
+      sleep();
   }
-  while (false == halAdcFinished);
-  //while (ADCSRA & (1 << ADSC));
-  /* set by ISR */
+  while (ADCSRA & (1 << ADSC));
+
+   /* set by ISR */
   return ADC;
 }
 
 /*****************************************************************************
 *****************************************************************************/
 int8_t HAL_MeasureTemperature(void) {
   int32_t val;
-  uint8_t adcsrc = ADCSRC;
-  uint8_t adcsrb = ADCSRB;
-  uint8_t adcsra = ADCSRA;
-  uint8_t admux = ADMUX;
 
   ADCSRC = 10 << ADSUT0;
   ADCSRB = (1 << MUX5);
@@ -55,20 +51,11 @@ int8_t HAL_MeasureTemperature(void) {
   ADCSRA |= (1 << ADIF); /* clear flag */
   ADCSRA |= (1 << ADIE);
 
-  /* dummy cycle after REF change (suggested by datasheet) */
+  // dummy cycle after REF change (suggested by datasheet)
   HAL_AdcMeasure();
 
   val = HAL_AdcMeasure();
 
-  ADCSRA = adcsra;
-  ADCSRB = adcsrb;
-  ADCSRC = adcsrc;
-  ADMUX = admux;
+  ADCSRA = 0;
   return (int)((1.13 * val - 272.8)) + HAL_TEMPERATURE_CALIBRATION_OFFSET - 3;
 }
-
-/*****************************************************************************
-*****************************************************************************/
-ISR(ADC_vect, ISR_BLOCK) {
-  halAdcFinished = true;
-}