＃i nclude "C8051F020.h" 
＃i nclude "stdio.h"

#define SYSCLK       11059000
#define BAUDRATE     9600
/*************************************************************/
#define WDTDISABLE  {WDTCN=0xDE;WDTCN=0xAD;}
/************************************************************/
/************************************************************/
void DELAY(void)
{
  int i,j;
  for(i=255;i>=0;i--)
    for(j=255;j>=0;j--); 

}
/*************************************************************/

void SYSCLK_Init (void)
{
 int i;
 OSCXCN=0x67;
 for(i=255;i>=0;i--);

 while (!(OSCXCN & 0x80)) ;    //11.059m hz
 OSCICN=0x88;
}

void UART0_Init (void)
{
   SCON0   = 0x50;                     // SCON0: mode 1, 8-bit UART, enable RX
   TMOD    = 0x20;                     // TMOD: timer 1, mode 2, 8-bit reload
   TH1    = -(SYSCLK/BAUDRATE/16);     // set Timer1 reload value for baudrate   
   TL1    = -(SYSCLK/BAUDRATE/16);     // set Timer1 reload value for baudrate
   TR1    = 1;                         // start Timer1
   CKCON |= 0x10;                      // Timer1 uses SYSCLK as time base
   PCON  |= 0x80;                      // SMOD00 = 1
   TI0    = 1;                         // Indicate TX0 ready
}

void init_port() //初始化端口
{
 
 P1 = 0xFF;    
 P2 = 0xFF;
 P3 = 0xFF;
 P3MDOUT=0xff;    //pull-push MODE
 P2MDOUT=0x00;  //open-drain MODE
 P1MDOUT=0xff;    //pull-push MODE
}

void main(void)  //initial micro controller
{ 
  unsigned char i;
  WDTDISABLE;

  SYSCLK_Init();
  
  XBR0 = 0x04; // XBAR0: Initial Reset Value 
  XBR1 = 0x04; // XBAR1: Initial Reset Value
  XBR2 = 0x40; // XBAR2: Initial Reset Value
  
  init_port();


  UART0_Init ();


  P2MDOUT=0x00;
  P2=0xff; //接受數字輸入

  while(1)
  {
    for(i=0xff;i>0;i--)
 { 
    P2MDOUT=0x00;
       P2=0xff;
   P1=i;
   printf("Now P2=%x\n",P2);
   DELAY();
 }
  }

}