uart_forum.c

#include <avr/io.h>

#include <inttypes.h>

#include <avr/interrupt.h>

#include <avr/signal.h>

#include <delayms.c>

#ifndef F_CPU

#define F_CPU 16000000           /* Oszillator-Frequenz in Hz */

#endif

#define UART_BAUD_RATE 9600

#define UART_BAUD_CALC(UART_BAUD_RATE,F_OSC) ((F_CPU)/((UART_BAUD_RATE)*16L)-1)

//globals

volatile uint8_t command[3];

volatile uint8_t sreg_temp;

volatile uint8_t bytecountSen;

SIGNAL(SIG_UART_TRANS)  

//ISR for transmitting via serial Interface

{

  if (bytecountSen==3)  //bytes 0 bis 2 sind gesendet, also die 3 byte des Befehls

      bytecountSen==0;    

  else

    {

      while (!(UCSRA & (1<<UDRE)));    //warten bis Senden moeglich 

      UDR = command[bytecountSen];    //der hier erzeugte Interrupt zird getsartet nachdem

      bytecountSen++;            //dies ISR abgearbeitet ist.

    } 

}

SIGNAL(SIG_UART_RECV)

//ISR for receiving a sign via serial Interface

{

uint8_t data;

data = UDR;

 switch (data)

 {

   case 'a': {ToggleBit(PORTC,PC0); break;}

   case 'b': {ToggleBit(PORTC,PC1); break;}

   case 'c': {ToggleBit(PORTC,PC2); break;}

   case 'd': {ToggleBit(PORTC,PC3); break;}

 }

}

int main(void)

{

uint8_t i;

//Initialization UART

UBRRH=(uint8_t)(UART_BAUD_CALC(UART_BAUD_RATE,F_CPU)>>8);

UBRRL=(uint8_t)UART_BAUD_CALC(UART_BAUD_RATE,F_CPU);

UCSRB |= (1<<RXEN) | (1<<TXEN); //enable RxD & TxD

UCSRB |= (1<<RXCIE) | (1<<TXCIE);

//command generation

command[0] = 0xff;

command[1] = 0x00;

command[2] = 0x34;

sei();

DDRC = 0xFF;

PORTC = 0x00;

//main loop

for(;;)

 {

  while (!(UCSRA & (1<<UDRE)));

  bytecountSen = 1;

  UDR = command[0];

  delayms(500);

 } 

}