tunermon.cpp

#include <iostream>
#include <iomanip>
#include <string>
#include <math.h>
#include <arpa/inet.h> // for ntohs
#include "serial.h"

using namespace std;

float decodePwr( unsigned short raw )
{
	float result = -1.0;
	
	if ( raw < 256 )
	{
		// 0 .. 100 w
		result = (((float)(raw)) / 255.0) * 100.0;
	}
	else
	{
		// 101 .. 1000
		raw -= 256.0;
		result = 100.0 + (900.0 * (((float)raw)/768.0));
	}
	return result;
}

int main( int argc, char* argv[] )
{
    SerialPort port;
    int bytesRead = 0;
    unsigned char buf[8+1];
    
    if ( port.init("/dev/ttyUSB1", B38400) != -1 )
    {
    
        while ( true )
        {
        	unsigned char c = 0;
        	
            bytesRead = port.readFully( &c, 1 );
            
            if ( bytesRead == 1 )
            {
            	if ( (int)c < 0x04 ) 
            	{         	
    	            buf[0] = c;
	            	bytesRead = port.readFully( &buf[1], 7 );
	            	            		
           
				    if ( bytesRead == 7 )
				    {
				        // meter telemetry
				        unsigned short *p = (unsigned short*)buf;
				        unsigned short fwd = ntohs(*p++);  // fwd power
				        unsigned short ref = ntohs(*p++);  // ref power
				        unsigned short wtf = ntohs(*p++);  // don't know
				        unsigned short eom = ntohs(*p++);  // always 0x3b3b ";;"
				        
				        if ( eom == 0x3b3b ) 
				        {
				        	if ( fwd > 0 )
				        	{
						        float wattsFwd = decodePwr(fwd);
						        float wattsRef = decodePwr(ref);
						        float rawRatio = sqrt( wattsRef / wattsFwd );
						        float vswr     = (1.0 + rawRatio ) / (1.0 - rawRatio );
						        
						        cout << "Forward:   " << wattsFwd << " W" << endl;
						        cout << "Reflected: " << wattsRef << " W" << endl;
						        cout << "VSWR:      " << abs(vswr) << " : 1" << endl << endl;
				            }
				        }
				        else
				        {
				            cout << "unknown read from port: " << 
				            "fwd: " << std::hex << fwd << endl << 
				            "ref: " << ref << endl <<
				            "wtf: " << ref << endl <<
				            "eom: " << eom << endl;                    
				        }              
				    }
				    else
				    {
				        cout << "bytes read == " << bytesRead << endl;
				    }
				}
				else
				{
					cout << "Response: " << (char)c << endl;
				}
		    }
		    else
		    {
		    	cout << "Read error" << endl;
		    }
        } // while (true)
    }
    else
    {
    	cout << "problem opening port" << endl;
    }
    return 0;
}