原创 nios II 实验一 LED流水灯

#include "system.h"                                  //包含基本的硬件描述信息
#include "altera_avalon_pio_regs.h"         //包含基本的IO寄存器信息
#include "alt_types.h"                               //Altera定义的数据类型
#include "unistd.h"                                    //延时函数       

#define led  *(volatile unsigned char *) LED_BASE   //定义端口

int main(void)
{

  led = 0x02;
  alt_u8 dir = 0;
 
  while(1)
  {
        if(led & 0x81)
        {
          dir = (dir ^ 0x1);
        }
   
        if(dir)
        {
          led = led >> 1;
        }
        else
        {
          led = led << 1;
        }
  
  usleep(50000);     //延时50000us
  }
  return 0;
 
}