From c7c5bdf661e98bb61688d1a4b2f4162a11ea146e Mon Sep 17 00:00:00 2001
From: Rob Tillaart <rob.tillaart@gmail.com>
Date: Sun, 29 Sep 2013 12:35:28 +0200
Subject: [PATCH] + finalized support for DHT21 + made TIMEOUT depends on clock
 ==> F_CPU

---
 libraries/DHTlib/dht.cpp                      | 26 ++-----------------
 .../{dht_test1.pde => dht_test1.ino}          |  5 ++--
 2 files changed, 5 insertions(+), 26 deletions(-)
 rename libraries/DHTlib/examples/dht_test1/{dht_test1.pde => dht_test1.ino} (96%)

diff --git a/libraries/DHTlib/dht.cpp b/libraries/DHTlib/dht.cpp
index 5237f3d0..c4d31267 100644
--- a/libraries/DHTlib/dht.cpp
+++ b/libraries/DHTlib/dht.cpp
@@ -22,7 +22,7 @@
 
 #include "dht.h"
 
-#define TIMEOUT 10000
+#define TIMEOUT (F_CPU/1600)    // unsigned int in code, for higher CPU speeds this might exceed MAXINT.
 
 /////////////////////////////////////////////////////
 //
@@ -62,29 +62,7 @@ int dht::read11(uint8_t pin)
 // DHTLIB_ERROR_TIMEOUT
 int dht::read21(uint8_t pin)
 {
-	// READ VALUES
-	int rv = read(pin);
-	if (rv != DHTLIB_OK)
-    {
-		humidity    = DHTLIB_INVALID_VALUE;  // invalid value, or is NaN prefered?
-		temperature = DHTLIB_INVALID_VALUE;  // invalid value
-		return rv; // propagate error value
-	}
-
-	// CONVERT AND STORE
-	humidity = bits[0] + bits[1] * 0.00390625;  // == 1/256.0
-    temperature = (bits[2] & 0x7F) + bits[3] * 0.00390625;
-    
-	if (bits[2] & 0x80) // negative temperature
-	{
-		temperature = -temperature;
-	}
-
-	// TEST CHECKSUM
-	uint8_t sum = bits[0] + bits[1] + bits[2] + bits[3];
-	if (bits[4] != sum) return DHTLIB_ERROR_CHECKSUM;
-
-	return DHTLIB_OK;
+        return read22(pin);  // dataformat identical to DHT22
 }
 
 // return values:
diff --git a/libraries/DHTlib/examples/dht_test1/dht_test1.pde b/libraries/DHTlib/examples/dht_test1/dht_test1.ino
similarity index 96%
rename from libraries/DHTlib/examples/dht_test1/dht_test1.pde
rename to libraries/DHTlib/examples/dht_test1/dht_test1.ino
index 9e23834a..a60460e1 100644
--- a/libraries/DHTlib/examples/dht_test1/dht_test1.pde
+++ b/libraries/DHTlib/examples/dht_test1/dht_test1.ino
@@ -13,7 +13,8 @@
 dht DHT;
 
 #define DHT11_PIN 4
-#define DHT22_PIN 5
+#define DHT21_PIN 5
+#define DHT22_PIN 6
 
 void setup()
 {
@@ -55,7 +56,7 @@ void loop()
   
     // READ DATA
   Serial.print("DHT21, \t");
-  int chk = DHT.read21(DHT21_PIN);
+  chk = DHT.read21(DHT21_PIN);
   switch (chk)
   {
     case DHTLIB_OK: