我写的通过SPI口显示模拟量的小程序，刚学几天的可以看看（刚刚注册，算是我的贡献吧，其实我也刚学几天，呜呜。。。）

#include <hidef.h>      /* common defines and macros */
#include <mc9s12dg128.h>     /* derivative information */

#pragma LINK_INFO DERIVATIVE "mc9s12dg128b"
unsigned char DispBuf0,DispBuf1,DispBuf2;
const unsigned char LED7Code[]={
 0xC0,  // 0
 0xF9,  // 1
 0xA4,  // 2
 0xB0,  // 3
 0x99,  // 4
 0x92,  // 5
 0x82,  // 6
 0xF8,  // 7
 0x80,  // 8
 0x90,  // 9
 0x88,  // A
 0x83,  // B
 0xC6,  // C
 0xA1,  // D
 0x86,  // E
 0x8E  // F
};
void Spi1Initial()         //spi initial
{
  SPI1BR=0x00;//8 state: 0 sppr2,sppr1,spper0,0,spr2,spr1,spr0 
  SPI1CR1=0x50;
  SPI1CR2=0x02;
 
}

void SpiSendData(unsigned char temp)
{
  
   while(!(SPI1SR&0x20));
   SPI1DR = temp;                        /* Send character */
}

 void delay(long m) {           //delay time
 
while(m--);
 }
 
unsigned char ad_result;
unsigned char ad_result1;
void TaskAD(void){
 ATD0CTL2=0xC0;
 ATD0CTL3=0x0C; 
 ATD0CTL4=0x06; //启动
 ATD0CTL5=0x80; //1通道A/D读入 ,右对齐
 
 asm{
  movb $80,ATD0STAT0
  }
// while(!(ATD0STAT0&0x80))
  // {}
               //显示A/D结果
  ad_result=ATD0DR0L;
   ad_result1=ATD0DR0H;
}

void main(void) {
  /* put your own code here */
   uint m;
   TaskAD();
   DispBuf1=(ad_result/16);
  DispBuf0=(ad_result%16);
  DispBuf2=(ad_result1%16);
 
  DDRT=0xff;
   Spi1Initial();
   PTT|=0x20;
  
   for(m=0;m<500;m++){
   SpiSendData(LED7Code[DispBuf0]);
   PTT=0x21;
   delay(100);
   SpiSendData(LED7Code[DispBuf1]);
   PTT=0x22;
   delay(100);
   SpiSendData(LED7Code[DispBuf2]);
   PTT=0x24;
   delay(100);
  
   }
}