UART. sende probl.

#include <avr/interrupt.h>

#include "usart.h"

ISR(USART_RXC_vect) 

{

Usart_Rx_Data();

}

int main(void)

{

uint16_t UBRR =(4000000/(16*9600))-1;// Interne Taktquelle

sei();    //Global Interrupt Enable Bit im Status Register gesetz

Usart_init(UBRR);

while(1)

{

Usart_Tx_Data('A');

}

}

#include <avr/io.h>

#include "usart.h"

void Usart_init(uint16_t baud)

{

UBRRH = (unsigned char)(baud>>8);

UBRRL = (unsigned char)baud;

/*

USART Control and Status Register B: UCSRCB

Bit 7 – RXCIE: RX Complete Interrupt Enable

Bit 6 – TXCIE: TX Complete Interrupt Enable

Bit 5 – UDRIE: USART Data Register Empty Interrupt Enable

Bit 4 – RXEN: Receiver Enable

Bit 3 – TXEN: Transmitter Enable

Bit 2 – UCSZ2: Character Size

Bit 1 – RXB8: Receive Data Bit 8

Bit 0 – TXB8: Transmit Data Bit 8

*/

UCSRB |= (1<<RXCIE) |(1<<TXEN) | (1<<RXEN);    //Inerrups-Flap bei RX aktiv, RX und TX aktiv 

/*

USART Control and Status Register C: UCSRC

Bit 7 – URSEL: Register Select

Bit 6 – UMSEL: USART Mode Select

Bit 5:4 – UPM1:0: Parity Mode

Bit 3 – USBS: Stop Bit Select

Bit 2:1 – UCSZ1:0: Character Size

Bit 0 – UCPOL: Clock Polarity

*/

UCSRC |= (1<<URSEL) | (1<<UCSZ1) | (1<<UCSZ0);    //Frame-Format: 8Data-Bits, 1Stop-Bit

}

void Usart_Tx_Data(unsigned char DATA)

{

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

    {

    }

    UDR = DATA;    

}