智能车制作

标题: 定时器输出比较为啥效果不对呢 [打印本页]

作者: 汐恋枫 时间: 2013-10-28 20:46
标题: 定时器输出比较为啥效果不对呢
#include <hidef.h>    /* common defines and macros */
#include "derivative.h"    /* derivative-specific definitions */
#include<MC9S12XS128.h>
static unsigned int a=0;

///锁相环
void PLL_Init(void)    //PLLCLK=2*OSCCLK*(SYNR+1)/(REFDV+1)
{                   //锁相环时钟=2*16*(2+1)/(1+1)=48MHz
REFDV=1;          //总线时钟=48/2=24MHz
SYNR=2;
while(!(CRGFLG&0x08));
CLKSEL=0x80;
}

void delayms(void) {
unsigned int i;
for(i=0;i<1335;i++);
}
//定时器初值
void ECT0_init(void)
{
  TIOS=0x01;
  TSCR2=0x86; //分频 24/64 相当于 2.67us
  TSCR1=0x80;
  TC0=37500; //  37500*2.67us=10ms定时时间

  TIE=0x01;
  TCTL2=0x02;
}

#pragma CODE_SEG __NEAR_SEG NON_BANKED
//#pragma CODE_SEF __NEAR_SEG NON_BANKED
interrupt 8 void Timer0_ISR(void)
{
//  unsigned int m;
a=a+1;
// m=TCNT;
  //TC0=m+37500;
  TFLG1_C0F=1;
// DisableInterrupts ;

  if(a>=100)
  {

PORTB=~PORTB;
//PORTB=0xfb;
a=0;
// delayms();
  }

}
#pragma CODE_SEG DEFAULT

void main(void)
  {
  /* put your own code here */

  PLL_Init();
  ECT0_init();

  DDRB=0xff;
  PORTB=0x00;
    EnableInterrupts;

  for(;;) {

_FEED_COP(); /* feeds the dog */

  } /* loop forever */
  /* please make sure that you never leave main */
}

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