求教大神们小弟的调速程序出了什么问题

飞思卡尔迷 · 发表于 2012-9-1 20:07:23

#include <hidef.h>    /* common defines and macros */
#include "derivative.h"    /* derivative-specific definitions */
void PLL_Init(void)
  {
REFDV=1;
SYNR=2;
while(!(CRGFLG&0x08));
CLKSEL=0x80;
  }

void PWM_Init(void)

  {
PWME_PWME1=0x00;
PWMPRCLK=0x33;
PWMSCLA=150;
PWMCLK_PCLK1=1;
PWMPOL_PPOL1=1;
PWMCAE_CAE1=0;
PWMCTL=0X00;
PWMPER1=100;
PWMDTY1=50;
PWME_PWME1=1;

}
  void PIT_Init(void)
  {
PITCFLMT_PITE=1;
PITFLT=1;
PITCE=1;
PITINTE=1;
PITMTLD0=239;
PITLD0=39999;
  }
  void PA_Init(void)
  {
PACTL=0x40;
PACNT=0x0000;
  }

void main(void) {
  /* put your own code here */
  DisableInterrupts;
PLL_Init();
PWM_Init();
PIT_Init();
PA_Init();

EnableInterrupts;

  for(;;) {
_FEED_COP(); /* feeds the dog */
  } /* loop forever */
  /* please make sure that you never leave main */
}
#pragma CODE_SEG NON_BANKED
void interrupt 66 PIT_ISR(void)
{
  float temp,v;
  DisableInterrupts;
  temp=PACNT;
  v=5.7344/temp;
  if(v<0.16)
PWMDTY1=PWMDTY1+2;
  if(v>0.24)
PWMDTY1=PWMDTY1-2;
  PACNT=0x0000;
}
****************************************
不知道为什么，我想调的是占空比，结果用示波器一看，PWM的频率居然一直在变！占空比也在变，但是码盘的转速不变。求教大神，我的程序出了什么问题。
ps：后来调速的程序是在PWM之后写的，PWM初始给的占空比是50%，频率100。