程序求解

欲驰

我是新手，对下面的程序不是很明白，求各位前辈精讲一下，谢谢！



#include <hidef.h>      /* common defines and macros */
#include <MC9S12XS128.h>     /* derivative information */
#pragma LINK_INFO DERIVATIVE "mc9s12xs128"


void PLLInit(void)
{
SYNR=0XC5;
REFDV=0XC1;
while(CRGFLG_LOCK==0);
CLKSEL_PLLSEL=1;

}
void delay(int t)
{ int i,j;
  //i=t;
  for(i=t;i>0;i--)
  {
   j=0x1300;
   while(j--);
  }
}
void PWMInit(void)
{
PWME=0x00;
PWMCTL_CON01=1;
PWMPRCLK=0X00;      
PWMSCLA=0X00;
PWMSCLB=0X00;
                 
PWMCLK=0X0FF;
PWMPOL=0X0FF;
PWMCAE=0X00;
PWMPER01=2000;
PWMDTY01=110;   
PWME=0X0FF;
}

void main(void) {  
  /* put your own code here */
  EnableInterrupts;
PLLInit();
PWMInit();
delay(1000);
for(;;)
{
PWMDTY01=153;
delay(8000);
PWMDTY01=110;
delay(8000);
PWMDTY01=77;
delay(8000);
PWMDTY01=110;
delay(8000);

} /* wait forever */
  /* please make sure that you never leave this function */
}