为什么IO口和我的AD口高电平总是读不出来

hude · 发表于 2010-5-21 23:22:38

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

void main(void)
{
  /* put your own code here */
      DDRA= 0x00;             //A口输出入
      DDRB= 0xFF; //B口输出
  PORTB=0XFF;

      EnableInterrupts;

  for(;;) {
if(PORTA_PA0==0)
{
   DDRB=0xFF;
   PORTB=0XF0;
}
else if(PORTA_PA0==1)
{
   DDRA=0xFF;
   PORTB=0X0F;
}
  } /* loop forever */
  /* please make sure that you never leave main */
}