Fix merge conflict with interrupt disable lock.

Author: tdicola

DHT.cpp

@@ -143,47 +143,46 @@ boolean DHT::read(void) {
   digitalWrite(_pin, LOW);
   delay(20);
 
-  // Turn off interrupts temporarily because the next sections are timing critical
-  // and we don't want any interruptions.
-  noInterrupts();
+  uint32_t cycles[80];
+  {
+    // Turn off interrupts temporarily because the next sections are timing critical
+    // and we don't want any interruptions.
+    InterruptLock lock;
 
-  // End the start signal by setting data line high for 40 microseconds.
-  digitalWrite(_pin, HIGH);
-  delayMicroseconds(40);
+    // End the start signal by setting data line high for 40 microseconds.
+    digitalWrite(_pin, HIGH);
+    delayMicroseconds(40);
 
-  // Now start reading the data line to get the value from the DHT sensor.
-  pinMode(_pin, INPUT);
-  delayMicroseconds(10);  // Delay a bit to let sensor pull data line low.
-
-  // First expect a low signal for ~80 microseconds followed by a high signal
-  // for ~80 microseconds again.
-  if (expectPulse(LOW) == 0) {
-    DEBUG_PRINTLN(F("Timeout waiting for start signal low pulse."));
-    _lastresult = false;
-    return _lastresult;
-  }
-  if (expectPulse(HIGH) == 0) {
-    DEBUG_PRINTLN(F("Timeout waiting for start signal high pulse."));
-    _lastresult = false;
-    return _lastresult;
-  }
+    // Now start reading the data line to get the value from the DHT sensor.
+    pinMode(_pin, INPUT);
+    delayMicroseconds(10);  // Delay a bit to let sensor pull data line low.
 
-  // Now read the 40 bits sent by the sensor.  Each bit is sent as a 50
-  // microsecond low pulse followed by a variable length high pulse.  If the
-  // high pulse is ~28 microseconds then it's a 0 and if it's ~70 microseconds
-  // then it's a 1.  We measure the cycle count of the initial 50us low pulse
-  // and use that to compare to the cycle count of the high pulse to determine
-  // if the bit is a 0 (high state cycle count < low state cycle count), or a
-  // 1 (high state cycle count > low state cycle count). Note that for speed all
-  // the pulses are read into a array and then examined in a later step.
-  uint32_t cycles[80];
-  for (int i=0; i<80; i+=2) {
-    cycles[i]   = expectPulse(LOW);
-    cycles[i+1] = expectPulse(HIGH);
-  }
+    // First expect a low signal for ~80 microseconds followed by a high signal
+    // for ~80 microseconds again.
+    if (expectPulse(LOW) == 0) {
+      DEBUG_PRINTLN(F("Timeout waiting for start signal low pulse."));
+      _lastresult = false;
+      return _lastresult;
+    }
+    if (expectPulse(HIGH) == 0) {
+      DEBUG_PRINTLN(F("Timeout waiting for start signal high pulse."));
+      _lastresult = false;
+      return _lastresult;
+    }
 
-  // Re-enable interrupts, timing critical code is complete.
-  interrupts();
+    // Now read the 40 bits sent by the sensor.  Each bit is sent as a 50
+    // microsecond low pulse followed by a variable length high pulse.  If the
+    // high pulse is ~28 microseconds then it's a 0 and if it's ~70 microseconds
+    // then it's a 1.  We measure the cycle count of the initial 50us low pulse
+    // and use that to compare to the cycle count of the high pulse to determine
+    // if the bit is a 0 (high state cycle count < low state cycle count), or a
+    // 1 (high state cycle count > low state cycle count). Note that for speed all
+    // the pulses are read into a array and then examined in a later step.
+    for (int i=0; i<80; i+=2) {
+      cycles[i]   = expectPulse(LOW);
+      cycles[i+1] = expectPulse(HIGH);
+    }
+  } // Timing critical code is now complete.
 
   // Inspect pulses and determine which ones are 0 (high state cycle count < low
   // state cycle count), or 1 (high state cycle count > low state cycle count).

DHT.h

@@ -57,4 +57,15 @@ class DHT {
 
 };
 
+class InterruptLock {
+  public:
+   InterruptLock() {
+    noInterrupts();
+   }
+   ~InterruptLock() {
+    interrupts();
+   }
+
+};
+
 #endif