#include <LPC21xx.H>                       /* LPC21xx definitions */

//=====================================================================
void wait (void)  {                        /* wait function */
  int  d;

  //比較以下這兩種循環的生成的匯編代碼
  for (d = 0; d < 1000000; d++);           	/* only to delay for LED flashes */
  
  while(--d);          					   					/* only to delay for LED flashes */
}

//======================================================================
int main (void) {
  unsigned int i;                          	/* LED var */

  //PINSEL0=0x00000000;  //設置所有引腳連接GPIO
  PINSEL1=0x00000000;
    
  IODIR0 = 0x00FF0000;                     /* P0.16..23 defined as Outputs */

  while (1)  {                             /* Loop forever */
    for (i = 1<<16; i < 1<<23; i <<= 1) {  /* Blink LED 0,1,2,3,4,5,6 */
      IOSET0 = i;             							/* Turn on LED */
      //IOSET0 = (i-1)&0xFF0000;             /* Turn on LED */
      wait ();                             /* call wait function */
      IOCLR0 = i;             						/* Turn off LED */
      //IOCLR0 = (i-1)&0xFF0000;             /* Turn off LED */
    }
    for (i = 1<<23; i > 1<<16; i >>=1 ) {  /* Blink LED 7,6,5,4,3,2,1 */
      //IOSET0 = (i-1)&0xFF0000;             /* Turn on LED */
      IOSET0 = i;             						/* Turn on LED */
      wait ();                             /* call wait function */
      //IOCLR0 = (i-1)&0xFF0000;             /* Turn off LED */
      IOCLR0 = i;             						/* Turn off LED */
    }
  }
}