原创 AVR GCC通讯例程[原创]

一个不错的AVR GCC通讯例程，已经验证无误，此为GCC串口通讯实验绝佳学习资料；

功能说明：
1.开机串口发送 hello word!
2.8个LED逐一点亮
3.通过串口控制LED的亮灭
例如：
LED00   LED0灯亮
LED01   LED0灯灭

LED02   LED全灭
LED03   LED全亮

使用MEGA162实验成功！不敢独享，公布如下：

-----------------------------------------------------------------------------------------------------------

/***************************************************************************** 
*         - COM.H -
*****************************************************************************/

#ifndef COM_INCLUDED
#define COM_INCLUDED

＃i nclude <avr/io.h>  

#define UART_PORT  PORTD  //UART port number
#define UART_RX   (0)   //RX pin number
#define UART_TX   (1)   //TX pin number

extern void InitUART(long clockFreq, long Baud); //Initialize UART and buffers
extern int  SendByte(char DataByte);
extern int  GetByte(void);

#endif

----------------------------------------------------------------------------------------------------------

/*****************************************************************************
*                                    Com.c
*
*****************************************************************************/
＃i nclude <Com.h>
/*****************************************************************************
*
*/
void InitUART(long clockFreq, long Baud)
{
  char temp;
 
  Baud = clockFreq/Baud/16-1; 
  UBRR0L = (unsigned char)Baud;      //Update baud rate register -> BAUDRATECODE_LO;
  UBRR0H = (unsigned char)(Baud >> 8); //Update baud rate register -> BAUDRATECODE_HI;
  UCSR0A = 0xC0;      //0b1100 0000  = Clear tx complete bit
  //Enable receive interrupt, and the UART's receiver and transmitter.
  UCSR0B = 0x18;      //0b10011000  = 0x98
  UCSR0C = 0x86;      //0b10000110  = 0x86 
}

/*****************************************************************************
* Send a char to the UART. The UDRE bit is monitored and the char is sent when
* the bit is set high.
*/
int SendByte(char DataByte)
{
   if(DataByte=='\n')
   SendByte('\r');
  loop_until_bit_is_set(UCSR0A,UDRE0);
  UDR0=DataByte;
  return 0;
}

/*****************************************************************************
* GetByte:
*/
int GetByte(void)
{
 loop_until_bit_is_set(UCSR0A,RXC0);
 return UDR0;
}

---------------------------------------------------------------------------------------------------------

/*
功能说明：
1.开机串口发送 hello word!
2.8个LED逐一点亮
3.通过串口控制LED的亮灭
例如：
LED00   LED0灯亮
LED01   LED0灯灭

LED02   LED全灭
LED03   LED全亮
*/

＃i nclude <avr/io.h>      // include I/O definitions (port names, pin names, etc)
＃i nclude <avr/signal.h>     // include "signal" names (interrupt names)
＃i nclude <avr/interrupt.h> // include interrupt support
＃i nclude <avr/delay.h>
＃i nclude <Com.h>
＃i nclude <string.h>
＃i nclude <stdio.h>

#define LED     PORTA
#define LEDDDR  DDRA

void delay_nms(unsigned int ms);
void LedControl(char bit, char status);

int main(void)
{
 unsigned char str[50], ch, n;
 unsigned char *pt;

 InitUART(F_CPU,9600);
    fdevopen(SendByte,GetByte);
 LEDDDR = 0xFF;    //Set PORTB as output;
 LED = 0xFF;       //LED off
 
 printf("Hello World.\r\n");

 LedControl(0,1);
 delay_nms(300);
 LedControl(1,1);
 delay_nms(300);
 LedControl(2,1);
 delay_nms(300);
 LedControl(3,1);
 delay_nms(300);
 LedControl(4,1);
 delay_nms(300);
 LedControl(5,1);
 delay_nms(300);
 LedControl(6,1);
 delay_nms(300);
 LedControl(7,1);
 delay_nms(300);

    LedControl(0,2);
   
 while(1)
  {
   n = 0;
   while((ch = GetByte())!= '\r')
   {
    str[n++] = ch;
   }
   str[n] = 0x00;
   pt = strstr(str,"LED");
   if(pt)
    {
     LedControl((pt[3]-0x30),(pt[4]-0x30));
    }
   else
    {
     printf("You type in: %s\n", str);
    }
  }
 return 0;
}

void delay_nms(unsigned int ms)
{
int i;
 for(i = 0; i<ms; ++i)
 {
  _delay_ms(1);
 }
}

/*******************************************
***********Control Led On/Off***************
*******************************************/
void LedControl(char bit, char status)
{
 switch (status) //LED ON
 {
  case 0: //clear Led bit off
   LED |= 1<<bit;
   break;
  case 1: //set Led bit on
   LED &= ~(1<<bit);
   break;
  case 2: //clear Led bit off
   LED = 0xFF;
   break;
  case 3: //set Led bit on
   LED = 0x00;
   break;
  default:
   break;
 }
}