XMega USART in SPI-Mode, CS-Problem

void UART_5004_write(const uint8_t adr, const uint32_t data){

  PORTC.OUTCLR = (1<<CS_5004_PIN);

  while (!(USARTC1.STATUS & USART_DREIF_bm));

  USARTC1.DATA  = adr;

  while(!(USARTC1.STATUS & USART_TXCIF_bm));

  USARTC1.DATA = (data>>16);

  /while(!(USARTC1.STATUS & USART_TXCIF_bm));

  USARTC1.DATA = (data>>8);

  while(!(USARTC1.STATUS & USART_TXCIF_bm));

  USARTC1.DATA = (data);

  while(!(USARTC1.STATUS & USART_TXCIF_bm));

  PORTC.OUTSET = (1<<CS_5004_PIN);

  _delay_us(10);

} 

void PE5004_init_UART(void){

  PORTC.DIRSET = (1<<SCK_5004_PIN)|(1<<MOSI_5004_PIN)|(1<<CS_5004_PIN);

  PORTC.OUTSET = (1<<CS_5004_PIN);

  PORTC.DIRCLR = (1<<MISO_5004_PIN);

  PORTD.DIRCLR = (1<<INT_5004_PIN);

  USARTC1.CTRLA = 0;

  USARTC1.CTRLB = 0x1C;  // TX Enabled, Rx enabled, Double speed

  USARTC1.CTRLC = 0xC0;  // UART in SPI-Mode, MSB First, 

  USARTC1.BAUDCTRLA = 0x05;  // 32 MHz/(2*(5+1)) = 32 MHz / 12 = 2,666 MHz // Evtl auch 0x04 möglich -> 3,2 MHz  

  UART_5004_write(0x05, 0x02);    // Select SPI

  UART_5004_write(0x02, (WAITCOL<<12)|WAITROW);

  UART_5004_write(0x03, (SinePush<<23)|(SINF<<18)|(SINA<<12)|(PWRI<<11)|(GCO<<4)|DACREF);

  UART_5004_write(0x04, PCO);

}