#include <avr/io.h>          
void delay_sec(int sec);      
     
int main()
{
 unsigned int count1=16;  
 unsigned int count2=8;
 float a=2;   
     
 float b=0.5;
 
 DDRA = 0xff;                 
 while(1)
 {
  PORTA = count1+count2; 
  delay_sec(1);      
  count1=count1*a;
  count2=count2*b;
  if(count1==128)
  {    
   a=0.5;
   b=2;
  }  
  else if(count1==16)   { 
   a=2;
   b=0.5;
  }
 }
}
     
void delay_sec(int sec)
{
 volatile int i, j, k;
 for (i=0; i<sec; i++)
 {
  for (j=0; j<500; j++)
  {
   for (k=0; k<500; k++)
   ;
  }
 }
}
     
void delay_sec(int sec)
{
 volatile int i, j, k;
 for (i=0; i<sec; i++)
 {
  for (j=0; j<500; j++)
  {
   for (k=0; k<500; k++)
   ;
  }
 }
}
     
#include <avr/io.h>
#include <stdlib.h>
#define F_CPU 16000000UL 
#include <util/delay.h> 
int main( )
{
 while(1)
 {
  DDRA = 0xff;
  unsigned char led = 0x01;
  int k;
  while(1) {
   for(k=0;k<7;k++) { 
   PORTA = led;
   led <<= rand()%3;
   _delay_ms(500); 
   }
  }
 }
}
 
형님들 부탁드립니다ㅜㅠ