void initClockmodes(void)
{
   DISABLE_ALL_INTERRUPTS();
   P1SEL &= ~0x01;
   INIT_GLED();
}
 
void blinkLeds(void)
{
  UINT16 timeOut = 0xffff;
  while(timeOut--);
  GLED ^=1;
}

void main(void)
{
 unsigned char i;
 initClockmodes();
 while(1)
 {
  Set_Main_Clock_Source(RC);
  for(i=0;i<20;i++)
  {
   blinkLeds();
  }
  Set_Main_Clock_Source(CRYSTAL);
   for(i=0;i<20;i++)
  {
    blinkLeds();
  }
 }
}


// Macro for setting the main clock oscillator source,

//turns off the clock source not used

//changing to XOSC will take approx 150 us

#define SET_MAIN_CLOCK_SOURCE(source) \
   do { \
      if(source) { \
        CLKCON |= 0x40; \
        while(!HIGH_FREQUENCY_RC_OSC_STABLE); \
        if(TICKSPD == 0){ \
          CLKCON |= 0x08; \
        } \
        SLEEP |= 0x04; \
      } \
      else { \
        SLEEP &= ~0x04; \
        while(!XOSC_STABLE); \
        asm("NOP"); \
        CLKCON &= ~0x47; \
        SLEEP |= 0x04; \
      } \
   }while (0)