refactored TIMEOUT

Author: RobTillaart

libraries/DHTlib/dht.cpp

@@ -1,11 +1,12 @@
 //
 // FILE: dht.cpp
 // AUTHOR: Rob Tillaart
-// VERSION: 0.1.10
+// VERSION: 0.1.11
 // PURPOSE: DHT Temperature & Humidity Sensor library for Arduino
 // URL: http://arduino.cc/playground/Main/DHTLib
 //
 // HISTORY:
+// 0.1.11 renamed DHTLIB_TIMEOUT
 // 0.1.10 optimized faster WAKEUP + TIMEOUT
 // 0.1.09 optimize size: timeout check + use of mask
 // 0.1.08 added formula for timeout based upon clockspeed
@@ -25,14 +26,6 @@
 
 #include "dht.h"
 
-// max timeout is 100usec.
-// For a 16Mhz proc that is max 1600 clock cycles
-// loops using TIMEOUT use at least 4 clock cycli
-// so 100 us takes max 400 loops
-// so by dividing F_CPU by 40000 we "fail" as fast as possible
-#define TIMEOUT (F_CPU/40000)
-
-
 /////////////////////////////////////////////////////
 //
 // PUBLIC
@@ -135,13 +128,13 @@ int dht::read(uint8_t pin, uint8_t wakeupDelay)
  pinMode(pin, INPUT);
 
  // GET ACKNOWLEDGE or TIMEOUT
- unsigned int loopCnt = TIMEOUT;
+ unsigned int loopCnt = DHTLIB_TIMEOUT;
  while(digitalRead(pin) == LOW)
  {
  if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;
  }
 
- loopCnt = TIMEOUT;
+ loopCnt = DHTLIB_TIMEOUT;
  while(digitalRead(pin) == HIGH)
  {
  if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;
@@ -150,15 +143,15 @@ int dht::read(uint8_t pin, uint8_t wakeupDelay)
  // READ THE OUTPUT - 40 BITS => 5 BYTES
  for (uint8_t i = 0; i < 40; i++)
  {
- loopCnt = TIMEOUT;
+ loopCnt = DHTLIB_TIMEOUT;
  while(digitalRead(pin) == LOW)
  {
  if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;
  }
 
  unsigned long t = micros();
 
- loopCnt = TIMEOUT;
+ loopCnt = DHTLIB_TIMEOUT;
  while(digitalRead(pin) == HIGH)
  {
  if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;

libraries/DHTlib/dht.h

@@ -1,7 +1,7 @@
 //
 // FILE: dht.h
 // AUTHOR: Rob Tillaart
-// VERSION: 0.1.10
+// VERSION: 0.1.11
 // PURPOSE: DHT Temperature & Humidity Sensor library for Arduino
 // URL: http://arduino.cc/playground/Main/DHTLib
 //
@@ -18,7 +18,7 @@
 #include <Arduino.h>
 #endif
 
-#define DHT_LIB_VERSION "0.1.10"
+#define DHT_LIB_VERSION "0.1.11"
 
 #define DHTLIB_OK 0
 #define DHTLIB_ERROR_CHECKSUM -1
@@ -28,6 +28,12 @@
 #define DHTLIB_DHT11_WAKEUP 18
 #define DHTLIB_DHT22_WAKEUP 1
 
+// max timeout is 100usec.
+// For a 16Mhz proc that is max 1600 clock cycles
+// loops using TIMEOUT use at least 4 clock cycli
+// so 100 us takes max 400 loops
+// so by dividing F_CPU by 40000 we "fail" as fast as possible
+#define DHTLIB_TIMEOUT (F_CPU/40000)
 
 class dht
 {