#include <12F675.h>
#device adc=8

#FUSES WDT                       //Watch Dog Timer
#FUSES EC_IO
#FUSES NOCPD                     //No EE protection
#FUSES NOPROTECT                 //Code not protected from reading
#FUSES NOMCLR                    //Master Clear pin used for I/O
#FUSES PUT                       //Power Up Timer
#FUSES NOBROWNOUT                //No brownout reset
#FUSES BANDGAP_HIGH          
#use delay(clock=10M)
#use rs232(baud=4800,parity=N,xmit=PIN_A4,rcv=PIN_A1,bits=8,stream=1,restart_wdt,invert)


char utc[6],status,lat[8],lon[8],speed[6]={'0'}, bearing[6]={'0'}, date[6], checksum[2];

void calc_cs()
{int cs=0x35;
 int i;
 
 for(i=0;i<6;i++)cs^=utc[i];
 cs^=status;
 for(i=0;i<8;i++)cs^=lat[i];
 for(i=0;i<8;i++)cs^=lon[i];
 for(i=0;i<4;i++)cs^=speed[i];
 for(i=0;i<6;i++)cs^=bearing[i];
 for(i=0;i<6;i++)cs^=date[i];
 
 checksum[0]=(cs/16)+48;
 checksum[1]=(cs%16)+48;
 if(checksum[0]>57)checksum[0]+=7;
 if(checksum[1]>57)checksum[1]+=7;
}

void main()
{  int i;
   char temp;

   setup_adc_ports(NO_ANALOGS|VSS_VDD);
   setup_adc(ADC_OFF);
   setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
   setup_wdt(WDT_2304MS);
   setup_timer_1(T1_DISABLED);
   setup_comparator(NC_NC);
   setup_vref(FALSE);

    delay_ms(10);
    
    //printf("\n\rnmea converter for th-d7 by TB2HL \n\r");

   while(true)
   {start:
    restart_wdt();
     speed[2]='0';
     speed[3]='0';
     speed[4]='0';
     
     bearing[0]='0';
     bearing[1]='0';
     bearing[2]='0';
     bearing[3]='0';
     bearing[4]='0';
     
     while(getch()!='$') restart_wdt();
     if(getch()!='G') goto start;
     if(getch()!='P') goto start;
     if(getch()!='R') goto start;
     if(getch()!='M') goto start;
     if(getch()!='C') goto start;
     getch();                               // ,
     
     for(i=0;i<6;i++)utc[i]=getch();
     
     while(getch()!=',');
     status=getch();
     getch();
     lat[0]=getch();
     lat[1]=getch();
     lat[2]=getch();
     lat[3]=getch();
     getch();
     lat[4]=getch();
     lat[5]=getch();
     lat[6]=getch();
     getch(); //4.hane
     getch(); //virgül
     lat[7]=getch(); //N-S
     
     getch();
     getch();
   
     lon[0]=getch();
     lon[1]=getch();
     lon[2]=getch();
     lon[3]=getch();
     getch(); // .
     lon[4]=getch();
     lon[5]=getch();
     lon[6]=getch();
     getch();  // 4. hane
     getch();  //virgül
     lon[7]=getch(); // E-W
     
     getch();// ,
     
     i=0;
     while(i<6)
     {temp=getch();
      if(temp==',') break;
      speed[i++]=temp;
     }

     i=0;
     while(i<6)
     {temp=getch();
      if(temp==',') break;
      bearing[i++]=temp;
     }
     
     date[0]=getch();
     while(date[0]==',')
     {date[0]=getch();}
     
     for(i=1;i<6;i++)date[i]=getch();
    
    restart_wdt();
    calc_cs();
    
    printf("$GPRMC,");
    for(i=0;i<6;i++) printf("%c",utc[i]);
    printf(",%c,",status);
    printf("%c%c%c%c.%c%c%c,%c,",lat[0],lat[1],lat[2],lat[3],lat[4],lat[5],lat[6],lat[7]);
    printf("0%c%c%c%c.%c%c%c,%c,",lon[0],lon[1],lon[2],lon[3],lon[4],lon[5],lon[6],lon[7]);
    for(i=0;i<4;i++) printf("%c",speed[i]);
    printf(",");
    for(i=0;i<6;i++) printf("%c",bearing[i]);
    printf(",");
    for(i=0;i<6;i++) printf("%c",date[i]);
    printf(",,,N*%c%c\r\n",checksum[0],checksum[1]);
    
   }

}