但它给出了像 avr/io.h 这样的错误没有这样的文件或 Directo
while (1) 
{
     //INIT USART
     UCSRB = 0x18;      //reciever enable , transmitter enable
     UCSRC = 0x86;      //8 bit , 1 stop bit ,
     UBRRH = 0;
     UBRRL = xtal/16/baud-1;
     while(1)
     {
         printf("Hello World");
     }
}
}