RS232 bei Atmega 16 Datenverlust

#include <avr/io.h>

#define FOSC 8000000 // Set clock Speed in Hz

#define BAUD 9600 // Set baud rate

#define UBRR_Value FOSC/16/BAUD-1 // Set baud rate value in baud rate register

void USART_Init( unsigned int ubrr)

{

UBRRH = (unsigned char)(ubrr>>8); // Set baud rate in high- and low-register

UBRRL = (unsigned char)ubrr;

UCSRC = (1<<UCSZ1)|(1<<UCSZ0); // Set frame format: 8data, 1stop bit

UCSRB = (1<<RXEN)|(1<<TXEN); // Enable receiver and transmitter

}

void USART_Transmit(unsigned char data)

{

while ( !( UCSRA & (1<<UDRE)) ); // Wait for empty transmit buffer

UDR = data; // Put data into buffer, sends the data

}

unsigned char USART_Receive(void)

{

while ( !(UCSRA & (1<<RXC)) ); // Wait for data to be received

return UDR; // Get and return received data from buffer

}

void USART_Flush(void) // Flush Receive-Buffer (entfernen evtl. vorhandener ungültiger Werte)

{

unsigned char dummy;

while (UCSRA & (1<<RXC))

dummy = UDR;

}

void main( void )

{

unsigned char data;

USART_Init(UBRR_Value); // Init UART

USART_Flush(); // Flush Receive-Buffer

DDRA = 0xFF; // alle PINs an PortB als Ausgänge

while(1)

{

USART_Transmit(data = USART_Receive()); // receive on byte, send it

PORTA = data; // and write to Port B

}

}