//------------------------------------------------------------------------------
//ATMEGA16与PC机的通信实验1
//PC机发送一个字符给单片机，单片机收到后既在发光二极管进行显示，同时将其回传给PC
//单片机的发送和接收都采用查询方式
#include"ioavr.h"
#include"intrinsics.h"
#include"delayics.h"
//------------------------------------------------------------------------------
typedef unsigned char uchar;
typedef unsigned int  uint;
#define UDRE  5
#define RXC 7
//------------------------------------------------------------------------------
//端口初始化函数
void port_init()
{
  DDRB=0XFF;
  PORTB=0XFF;
  DDRD=0X02;
  PORTD=0XFF;
}
//------------------------------------------------------------------------------
//USART初始化函数
void usart_init()
{
  UCSRA=0X02;                   //置位U2X，倍速发送
  UCSRC=0X06;                   //选择字符长度为8位
  UBRRL=0X67;                   //设置波特率9600，查看datesheet
  UBRRH=0X00;
  UCSRB=0X18;                   //发送使能、接收使能
}
//------------------------------------------------------------------------------
//芯片初始化函数
void device_init()
{
  __disable_interrupt();
  port_init();
  usart_init();
}
//------------------------------------------------------------------------------
//发送5~8位数据位的帧
void usart_send_8(uchar i)
{
  while(!(UCSRA&(1<  UDR=i;
}
//------------------------------------------------------------------------------
//接收5~8位数据位的帧
uchar usart_receive_8()
{
  while(!(UCSRA&(1<  return(UDR);
}
//------------------------------------------------------------------------------
//main
void main()
{
  uchar temp;
  device_init();
  while(1)
  {
    temp=usart_receive_8();
    PORTB=~temp;
    usart_send_8(temp);
  }
}