Allow to set the resolution to either microseconds or microseconds

PID_v1/PID_v1.h

@@ -13,6 +13,8 @@ class PID
   #define MANUAL	0
   #define DIRECT  0
   #define REVERSE  1
+  #define MILLIS  0
+  #define MICROS  1
 
   //commonly used functions **************************************************************************
     PID(double*, double*, double*,        // * constructor.  links the PID to the Input, Output, and 
@@ -41,6 +43,9 @@ class PID
 										  //   once it is set in the constructor.
     void SetSampleTime(int);              // * sets the frequency, in Milliseconds, with which 
                                           //   the PID calculation is performed.  default is 100
+    void setResolution(int);			  // * Set the resolution of the getTime() function. 
+    									  //   MILLIS sets the resolution to milliseconds.
+    									  //   MICROS sets the resolution to microseconds.
 										  
 										  
 										  
@@ -53,6 +58,8 @@ class PID
 
   private:
 	void Initialize();
+	unsigned long getTime();    // * This will call either millis() or micros()
+	                            //   depending on the used resolution.
 	
 	double dispKp;				// * we'll hold on to the tuning parameters in user-entered 
 	double dispKi;				//   format for display purposes
@@ -73,6 +80,7 @@ class PID
 	double ITerm, lastInput;
 
 	unsigned long SampleTime;
+	double secondsDivider;
 	double outMin, outMax;
 	bool inAuto;
 };