SPI Read mit MSP430 (nRF24L01 Funkmodul)

unsigned char SPI_WriteByte(unsigned char dataByte) {

  #if NRF24L_SPI_NUMBER == 0

    while(!(IFG1&UTXIFG0))    //wait for transmission buffer to be empty

      ;;    

    IFG1 &=~URXIFG0;      //URXIFGx is automatically reset if the pending interrupt is served or when UxRXBUF is read.

    U0TXBUF = dataByte;          //fill buffer with desired data

    while(!(IFG1&URXIFG0))    //wait for reception to be completed

      ;;    

    while(!(TXEPT&U0TCTL))    //wait for reception to be completed

      ;;    

    dataByte = U0RXBUF;

    return dataByte;

  #else

    return 0;

  #endif

}

void NRF24L_Init(void) {

  //Initialize all I/O Ports

  #if NRF24L_SPI_NUMBER == 0    

    U0CTL = 0;

//    U0CTL &= ~I2C;  //SPI mode

    U0CTL |= CHAR;  //8-bit data

    U0CTL |= SYNC;  //synchronous mode (SPI)

    U0CTL |= MM;  //master mode (SPI)

    U0TCTL = 0;

    U0TCTL |= CKPH; 

    U0TCTL &= ~CKPL;   //data valid on rising edge 

    U0TCTL |= SSEL1 | SSEL0;    //SMCLK (valid for master mode only)

    U0TCTL |= STC;    //3-pin SPI mode: STE disabled.  

    U0BR1 = (CPU_SMCLK / NRF24L_SPI_BAUDRATE) >> 8;    //set baudrate

    U0BR0 = (CPU_SMCLK / NRF24L_SPI_BAUDRATE) & 0x00FF;

    U0MCTL = 0;      //modulator - for SPI mode and is recommended to be set to 000h    

    ME1 |= USPIE0;    //enable SPI module

    P3DIR |= BIT1;      //SIMO    

    P3SEL |= BIT1;

    P3DIR &= ~BIT2;      //SOMI  

    P3SEL |= BIT2;

    P3DIR |= BIT3;      //UCLK    

    P3SEL |= BIT3;  

  #else

    #error "Only SPI0 implemented for now!"

  #endif

  //IRQ signal

  NRF24L_IRQ_PDIR &= ~NRF24L_IRQ_BIT;

  P2IES |= NRF24L_IRQ_BIT;  //... on falling edge

  P2IFG &= ~NRF24L_IRQ_BIT;    //pre-clear flag

  P2IE |= NRF24L_IRQ_BIT;    //enable interrupt for IRQ pin

  //Chip enable signal

  NRF24L_CE_PDIR |= NRF24L_CE_BIT;

  NRF24L_CE_POUT &= ~NRF24L_CE_BIT;

  //Chip select signal

  NRF24L_CSN_PDIR |= NRF24L_CSN_BIT;

  NRF24L_CSN_POUT |= NRF24L_CSN_BIT;

  /* DEBUG STUFF START */

  //NRF24L_ISR();

  /* DEBUG STUFF END */

}