Merge branch 'master' of https://github.com/piettetech/PietteTech_DHT

# Conflicts:
#	spark.json

Author: piettetech

firmware/PietteTech_DHT.cpp

@@ -22,15 +22,15 @@
 /*
     Timing of DHT22 SDA signal line after MCU pulls low for 1ms
     https://github.com/mtnscott/Spark_DHT/AM2302.pdf
- 
+
   - - - -            -----           -- - - --            ------- - -
          \          /     \         /  \      \          /
           +        /       +       /    +      +        /
            \      /         \     /      \      \      /
             ------           -----        -- - --------
  ^        ^                ^                   ^          ^
  |   Ts   |        Tr      |        Td         |    Te    |
- 
+
     Ts : Start time from MCU changing SDA from Output High to Tri-State (Hi-Z)
          Spec: 20-200us             Tested: < 65us
     Tr : DHT response to MCU controlling SDA and pulling Low and High to
@@ -83,7 +83,7 @@ int PietteTech_DHT::acquire() {
         // return last correct measurement, (this read time - last read time) < device limit
         return DHTLIB_ACQUIRED;
     }
-    
+
     if (_state == STOPPED || _state == ACQUIRED) {
         /*
          * Setup the initial state machine
@@ -133,9 +133,21 @@ int PietteTech_DHT::acquire() {
         return DHTLIB_ERROR_ACQUIRING;
 }
 
-int PietteTech_DHT::acquireAndWait() {
+int PietteTech_DHT::acquireAndWait(uint32_t timeout=0) {
     acquire();
-    while(acquiring()) ;
+    uint32_t start = millis();
+    uint32_t wrapper;
+    while(acquiring() && (timeout == 0 || (millis() > start && (millis()-start) < timeout)));
+    if (timeout)
+    {
+        if (millis() < start) // millis counter wrapped
+        {
+            wrapper = (~start)+1;   // Compute elapsed seconds between "start" and counter-wrap to 0
+            timeout -= wrapper;     // Subtract elapsed seconds to 0 from timeout
+        }
+        // If millis counter didn't wrap, the next line will be a no-op.
+        while(acquiring() && (millis() < timeout));
+    }
     return getStatus();
 }
 

firmware/PietteTech_DHT.h

@@ -65,7 +65,7 @@ class PietteTech_DHT
     void begin(uint8_t sigPin, uint8_t dht_type, void (*isrCallback_wrapper)());
     void isrCallback();
     int acquire();
-    int acquireAndWait();
+    int acquireAndWait(uint32_t);
     float getCelsius();
     float getFahrenheit();
     float getKelvin();
@@ -79,11 +79,11 @@ class PietteTech_DHT
 #if defined(DHT_DEBUG_TIMING)
     volatile uint8_t _edges[41];
 #endif
-    
+
 private:
     void (*isrCallback_wrapper)(void);
     void convert();
-    
+
     enum states{RESPONSE=0,DATA=1,ACQUIRED=2,STOPPED=3,ACQUIRING=4};
     volatile states _state;
     volatile int _status;

firmware/examples/DHT_example.ino

@@ -51,7 +51,7 @@ void setup()
 
 
 // This wrapper is in charge of calling
-// mus be defined like this for the lib work
+// must be defined like this for the lib work
 void dht_wrapper() {
     DHT.isrCallback();
 }

spark.json

@@ -1,6 +1,6 @@
 {
     "name": "PietteTech_DHT",
-    "version": “0.0.2”,
+    "version": "0.0.4",
     "author": "Scott Piette scott.piette@gmail.com",
     "license": "GPL v3 (http://www.gnu.org/licenses/gpl.html)",
     "description": "Interrupt driven DHT11/21/22 Sensor library"