#define               is            ==
#define               pressed       0
#define               sw1           porta.f0
#define               sw1_dir       trisa.f0
/*******************************************/
char x=0;
void init()
{
  cmcon=7;
  trisa=1;
  trisb=0;
  portb=0;
  porta=0;
}
void ten();
void twenty();
void fiftey();
/*******************************************/
void main()
{
init();
porta=64;
while(1)
{
  if(sw1 is pressed){delay_ms(10);
                    while(sw1 is pressed );
                     delay_ms(10);
                     x++;
                     if(x is 4){x=0;porta=64;}
                    }
 if(x is 1)ten();
 if(x is 2 )twenty();
 if(x is 3)fiftey();

}

}
/*******************************************/
 void ten()
{              //10KHZ
  while(1)
  {porta=2;
  portb=1; delay_us(25);
  portb=0;delay_us(25);
   if(sw1 is pressed) return;
   }
}
/*******************************************/
void twenty()
{                         //20KHZ
while(1)
{ porta=4;
 portb=1; delay_us(25);
 portb=0; delay_us(25);
 if(sw1 is pressed) return;
}
}
/*******************************************/
void fiftey()                  //50KHZ
{ while(1)
{ porta=128;
 portb=1; delay_us(10);
 portb=0; delay_us(10);
 if(sw1 is pressed )return;
 }
}
/*******************************************/