#include <c8051f020.h>                    // SFR declarations





//------------------------------------------------------------------------------------
// Global CONSTANTS
//------------------------------------------------------------------------------------

#define SYSCLK 2000000                    // approximate SYSCLK frequency in Hz


unsigned long x;
//------------------------------------------------------------------------------------
// Function PROTOTYPES
//------------------------------------------------------------------------------------
void PORT_Init (void);


//------------------------------------------------------------------------------------
// MAIN Routine
//------------------------------------------------------------------------------------
void main (void) {
 
                
   WDTCN = 0xde;
   WDTCN = 0xad; //關閉看門狗
                 //沒有配置時鐘，默認內部2M晶振
   PORT_Init ();
   		

   while (1) { 
   for(x=0;x<=5000;x++);  
   P0=~P0;//按字節取反
   P1=~P1;
   P2=~P2;
   P3=~P3;
   P4=~P4;
   P5=~P5;
   P6=~P6;
   P7=~P7;
 
   }
}

//------------------------------------------------------------------------------------
// PORT_Init
//------------------------------------------------------------------------------------
//
// Configure the Crossbar and GPIO ports
//
void PORT_Init (void)
{
   XBR2    = 0x40;    // 使能交叉開關
   P0MDOUT |= 0xFF;   // 配置為推拉模式
   P1MDOUT |= 0xFF;
   P2MDOUT |= 0xFF;
   P3MDOUT |= 0xff;
   P74OUT|= 0xff;
}