FreqMesure.h

00001 /***************************************************************************************
00002 Measure the frequency of a 3.3v square wave signal once every second. The frequency range
00003 is 500Hz to 1000Hz with 50% duty cycle). In this code the on complet cycle is peiod is 
00004 masured after detcting the edge also a timeout timer is seting to detect open loop.
00005 *****************************************************************************************/
00006 
00007 void FreqMsur(){
00008     FreqMsurPin = ! (FreqMsurPin);   //Pin 23
00009     FreqTimeOut.start();
00010     // Ignore first part of the signal to detect the edge
00011     if(!FrequencyIn){ 
00012         while(!FrequencyIn){
00013             if (FreqTimeOut.read_ms() > 3)
00014                 break;
00015         }
00016     }
00017     else{
00018         while(FrequencyIn){
00019             if (FreqTimeOut.read_ms() > 3)
00020                 break;
00021         }
00022     }
00023     //This is the begining of the edge start the timer to masure
00024     FreqMsurT.start();
00025     if (FreqTimeOut.read_ms() > 3){
00026            FreqTimeOutHpn=1;
00027     }
00028     else{
00029             FreqTimeOutHpn=0;
00030     }
00031     FreqTimeOut.stop(); 
00032     FreqTimeOut.reset();
00033     if(!FreqTimeOutHpn){
00034         if(!FrequencyIn){
00035             while(!FrequencyIn){
00036             }
00037             while(FrequencyIn){
00038             }
00039         }
00040         else{
00041             while(FrequencyIn){
00042             }
00043             while(!FrequencyIn){
00044             }
00045         }    
00046         FreqMsurT.stop();
00047         float Period=FreqMsurT.read_us();
00048         Freq=1/Period*1000000.0+0.5;  //Adding 0.5 to round the frequency to nearst int
00049     }
00050     else{
00051         Freq=0xffff; 
00052     }                
00053     FreqTimeOut.stop();
00054     FreqMsurT.reset();
00055     //FreqMsurPin = ! (FreqMsurPin);
00056 }