ATmega8自适应波特率的实现(软件包)

Project Name: Method of auto-baudrate for ATmega8 
Date:         2006-June-01
Author:       Eighth Army
System crystal: Internal 8MHz by RC 
Compiler Reversion: IAR for AVR 412A
Additional information:
  1 Embedded system startup baudrate is 2400bps.
  2 Higher baud rate of PC is not recommend.(Ref. BAUD_RATE_ARRAY specification)
  3 After slaver returns "AA 55",it means the baud rate set completed.
  4 File name:Main.c
Debugging data:  AA 55  
*******************************************************************/

＃i nclude <iom8.h>
＃i nclude "INCLUDES.H"
＃i nclude "CONSTANTS.H"
＃i nclude "FUNCTIONS.H"
＃i nclude "VARIABLES.H"

const uchar BAUD_RATE_ARRAY[12] = {             
                    /* Embedded startup value -> PC     Repeat Times */
  0xA0,0X01,        /* 2400 */
  0xCF,0x00,        /* 4800                   -> 4800   5 Times */
  0x67,0x00,        /* 9600                   -> 9600   7 Times */
  0x33,0x00,        /* 19200                  -> 19200  10 Times */
  0x19,0x00,        /* 38400                  -> 38400  30 Times */
  0x10,0x00         /* 57600                  -> 57600  17 Times */
  };

/****** Super Loop body *******************************************/
void main( void ){
InitialSystem();  
while( 1 )
  {
  if( !( ucStatusProgram & bSET_BAUD )) 
    {
    if( uiTenor & bRECEIVED )
      {
      uiTenor &= ~bRECEIVED;
      if( ! Judge( &ucCommunicatorBuffer[0] ) )
        {
        ExchangeBaudRate( ( uchar *)&BAUD_RATE_ARRAY[ ucSearch ] );  
        ucSearch += 2;
        }
      else
        {
        PORTB |= ( 1 << INDICATE );
        ucStatusProgram |= bSET_BAUD;
        TransmitData( ucCommunicatorBuffer, 2 );
        }
      }
    }
  else
    {
    if( uiTenor & bRECEIVED )
      {
      uiTenor &= ~bRECEIVED;
      PORTB ^= ( 1 << INDICATE );
      TransmitData( ucCommunicatorBuffer, ucCommunicatorBuffer[1] );
      }
    }
  }
}
/*******************************************************************
@Fn: InitialSystem()
@Br: Initialization of system
@Pa: None
@Rt: None
*******************************************************************/
void InitialSystem( void ){
_DI();
ConfigTimerSystem();
ConfigParallelPort();
ConfigSerialPort();
ucSearch = 0;
_EI();
}
/*******************************************************************
@Fn: Delay_mS()
@Br: Non-Interrupt one milliSecond delay
@Pa: uiMS
@Rt: None
*******************************************************************/
void Delay_mS( uint uiMS ){
ulong ulMultiplex; 
ulMultiplex = ( ulong )uiMS * ( ulong )8;
while( ulMultiplex-- );
}
/*******************************************************************
@Fn: ConfigSerialPort()
@Br: Configuration of MCU
@Pa: None
@Rt: None
*******************************************************************/
void ConfigSerialPort( void ){
UCSRA = ( 1 << U2X );                       /* Double baud rate enabled */
UBRRH = 0x01;
UBRRL = 0xA0;                               /* 2400bps @ 8MHz */
UCSRB = ( 1 << RXCIE ) | ( 1 << TXEN ) | ( 1 << RXEN );       /*Enable the Rxc & RX & TX interrupt*/
UCSRC = ( 1 << URSEL ) | ( 1 << UCSZ1 ) | ( 1 << UCSZ0 );     /*8 bit Data*/  
}  
/*******************************************************************
@Fn: ConfigTimerSystem()
@Br: Configuration of TIMER on system
@Pa: None
@Rt: None
*******************************************************************/
void ConfigTimerSystem( void ){
TCCR0 = ( 1 << CS02 ) + ( 1 << CS00 );        /* clk/1024 */
TCNT0 = 0X00;
TIMSK = ( 1 << TOIE0 );                       /* Overflow enabled for TIMER_0*/
}  
/*******************************************************************
@Fn: ConfigTimerSystem()
@Br: Configuration of output port
@Pa: None
@Rt: None
*******************************************************************/
void ConfigParallelPort( void ){
PORTB = 0xFE;                             /*Set of all*/
DDRB = 0xFF;                              /*Set to output mode of all*/
}  
/*******************************************************************
@Fn: TransmitData()
@Br: Send a fram onto serial-bus
@Pa: ucpDataAddress: Point of data buffer
     ucLength: Length of data 
@Rt: None
*******************************************************************/
void TransmitData( uchar *ucpDataAddress, uchar ucLength ){
while( ucLength )
  {
  while(!( UCSRA & ( 1 << UDRE )));
  UDR = *ucpDataAddress++;
  ucLength--;
  }
}  
/*******************************************************************
@Fn: ExchangeBaudRate()
@Br: Exchange values for modify baud rate
@Pa: ucpChar: Character value
@Rt: None
*******************************************************************/  
void ExchangeBaudRate( uchar *ucpChar ){  
UCSRB &= ~( 1 << RXCIE ) | ( 1 << TXEN ) | ( 1 << RXEN );       
UBRRL = *ucpChar++;
UBRRH = *ucpChar++; 
UCSRB = ( 1 << RXCIE ) | ( 1 << TXEN ) | ( 1 << RXEN );
}
/*******************************************************************
@Fn: Judge()
@Br: Judge baud rate according to the received data
@Pa: ucpCharacter: Pointer of received data buffer 
@Rt: 1:Right  0:Error
*******************************************************************/  
uchar Judge( uchar *ucpCharacter ){
if(( *ucpCharacter++ != CHAR0 ) || ( *ucpCharacter++ != CHAR1 )) return FAILURE;
else
  return SUCCESS;
}

/* File name: INTERRUPTS.H */
＃i nclude <iom8.h>
＃i nclude "includes.h"
＃i nclude "CONSTANTS.H"
＃i nclude "FUNCTIONS.H"
＃i nclude "GLOBALS.H"

/*******************************************************************
@Fn: T0OVERFLOW_Handler
@Br: Service of Timer_0 interrupt
@Pa: None
@Rt: None
*******************************************************************/
#pragma vector = TIMER0_OVF_vect
__interrupt void T0OVERFLOW_Handler( void ){
TCNT0 = 0;  
}
/*******************************************************************
@Fn: USART_RX
@Br: Service of USART interrupt
@Pa: None
@Rt: None
*******************************************************************/
#pragma vector = USART_RXC_vect
__interrupt void USART_RX( void ){
ucCommunicatorBuffer[ ucReceiveCounter++ ] = UDR;
if( !( ucStatusProgram & bSET_BAUD ))
  {
  if ( ucReceiveCounter > 1 )
    {
    ucReceiveCounter = 0;
    uiTenor |= bRECEIVED; 
    }
  } 
else
  {
  if( ucReceiveCounter > 2 )
    {
    if( ucReceiveCounter >= ucCommunicatorBuffer[1] )
      {
      ucReceiveCounter = 0;
      uiTenor |= bRECEIVED;
      }
    }
  }
}

#ifndef CONSTANTS_H
#define CONSTANTS_H

/****** System Macro **********************************************************/
#define _EI()           SREG|=0X80
#define _DI()           SREG&=~0X80
#define SLEEP()         MCUCR|=(1<<SE);asm("sleep")

/****** Status Macro **********************************************************/
#define bSET_BAUD       0x01

/****** Tenor Macro ***********************************************************/
#define bRECEIVED       0x01

/****** Application Macro *****************************************************/
#define INDICATE        PB0
#define CHAR0           0xAA
#define CHAR1           0x55

#endif

#ifndef FUNCTIONS_H
#define FUNCTIONS_H

/****** Main.c ****************************************************************/
void InitialSystem( void );
void Delay_mS( uint uiMS );
void ConfigSerialPort( void );
void ConfigTimerSystem( void );
void ConfigParallelPort( void );
void TransmitData( uchar *ucpDataAddress, uchar ucLength );
void ExchangeBaudRate( uchar *ucpChar );
uchar Judge( uchar *ucpCharacter );

#endif

#ifndef VERIABLES_H
#define VERIABLES_H

uchar ucReceiveCounter;
uchar ucCommunicatorBuffer[64];
uint uiTenor;
uchar ucStatusProgram;
uchar ucSearch;

#endif

#ifndef GLOBALS_H
#define GLOBALS_H

extern uchar ucReceiveCounter;
extern uchar ucCommunicatorBuffer[64];
extern uint uiTenor;
extern uchar ucStatusProgram;
extern uchar ucSearch;

#endif

#ifndef INCLUDES_H
#define INCLUDES_H

＃i nclude <assert.h>
＃i nclude <ctype.h>
＃i nclude <float.h>
＃i nclude <math.h>
＃i nclude <stddef.h>
＃i nclude <stdio.h>
＃i nclude <stdlib.h>
＃i nclude <string.h>
＃i nclude <sysmac.h>

#define Max(A,B) (A>B:A?B)
#define Min(A,B) (A<B:A?B)

#ifndef uchar
#define uchar unsigned char
#endif

#ifndef uint
#define uint unsigned int
#endif

#ifndef ulong
#define ulong unsigned long
#endif

#ifndef SUCCESS
#define SUCCESS 1
#endif

#ifndef FAILURE
#define FAILURE 0
#endif
#endif