Interrupt Nios II RS232 / Usart

I red the other thread and now my isr works, but now the write function does not work..nothing is send, only the RXD comes

volatile int counter;

init RXD

/* flush any characters sitting in the holding register */

IORD(UART_RS232_BASE, 0);

IORD(UART_RS232_BASE, 0);

/* reset most of the status register bits */

IOWR(UART_RS232_BASE, 2, 0x00);

/* install IRQ service routine */

alt_irq_register(UART_RS232_IRQ, 0, serial_irq_0);

/* enable irq for Rx. */

IOWR(UART_RS232_BASE, 3, 0x0080);

The ISR is so:

static void serial_irq_0(void* context , alt_u32 id)

{

unsigned int stat,temp;

int chr[3];

// message[0]=getc(fp_read);

/* get serial status */

stat = IORD(UART_RS232_BASE, 2);

/* character Rx */

if (stat & 0x0080) {

message [counter]= IORD(UART_RS232_BASE, 0);

}

if(counter==2){

printf("char: %c%c%c",message[0],message[1],message[2]);

counter=0;

}

else

counter++;

}

In a Task I wrote this to write:

FILE *fp_write;

fp_write = fopen("/dev/uart_rs232", "w+"); //also used r+

if(fp_write)

{

//printf("Verbunden\n");

fwrite(pic_viewer->message, strlen(pic_viewer->message), 1, fp_write);

OSTimeDlyHMSM(0, 0, 0, (20));

//fwrite(msg,strlen(msg),1,fp);

//sprintf(msg,"%i",400);

//fwrite(msg, strlen(msg),1,fp);

//fprintf(fp, "Closing the UART file.\n");

fclose(fp_write);

sprintf(pic_viewer->message,"%s","00050200");

}

else

{

printf("Error/dev/ttyS0\n");

}