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MSP430G2121 SPI SDO and SDI

Other Parts Discussed in Thread: MSP430G2121, TEST

I am trying to create working SPI code for the MSP430G2121. I am referencing the example code provided by TI and using a logic analyzer to read the values on the MOSI and MISO lines. However, when I flash the code, the MOSI and MISO values are constantly 0x00 and 0xFF respectively.

Is there something I am missing in the setup?

msp430g2x21_usi_02.c
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 *******************************************************************************
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 *                       MSP430 CODE EXAMPLE DISCLAIMER
 *
 * MSP430 code examples are self-contained low-level programs that typically
 * demonstrate a single peripheral function or device feature in a highly
 * concise manner. For this the code may rely on the device's power-on default
 * register values and settings such as the clock configuration and care must
 * be taken when combining code from several examples to avoid potential side
 * effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware
 * for an API functional library-approach to peripheral configuration.
 *
 * --/COPYRIGHT--*/
//******************************************************************************
//  MSP430G2x21/G2x31 Demo - SPI full-Duplex 3-wire Master
//
//  Description: SPI Master communicates full-duplex with SPI Slave using
//  3-wire mode. The level on P1.4 is TX'ed and RX'ed to P1.0.
//  Master will pulse slave reset for synch start.
//  ACLK = n/a, MCLK = SMCLK = Default DCO
//
//  **** used with "msp430g2x21_usi_03.c"   ****
//
//                Slave                      Master
//             MSP430G2x21/G2x31          MSP430G2x21/G2x31
//             -----------------          -----------------
//            |              XIN|-    /|\|              XIN|-
//            |                 |      | |                 |
//            |             XOUT|-     --|RST          XOUT|-
//            |                 | /|\    |                 |
//            |          RST/NMI|--+<----|P1.2             |
//      LED <-|P1.0             |        |             P1.4|<-
//          ->|P1.4             |        |             P1.0|-> LED
//            |         SDI/P1.7|<-------|P1.6/SDO         |
//            |         SDO/P1.6|------->|P1.7/SDI         |
//            |        SCLK/P1.5|<-------|P1.5/SCLK        |
//
//  D. Dang
//  Texas Instruments Inc.
//  October 2010
//  Built with CCS Version 4.2.0 and IAR Embedded Workbench Version: 5.10
//******************************************************************************

#include <msp430.h>


int main(void)
{
  volatile unsigned int i;

  WDTCTL = WDTPW + WDTHOLD;             // Stop watchdog timer
  P1OUT =  0x10;                        // P1.4 set, else reset
  P1REN |= 0x10;                        // P1.4 pullup
  P1DIR = 0x01;                         // P1.0 output, else input
  USICTL0 |= USIPE7 +  USIPE6 + USIPE5 + USIMST + USIOE; // Port, SPI master
  USICTL1 |= USIIE;                     // Counter interrupt, flag remains set
  USICKCTL = USIDIV_4 + USISSEL_2;      // /16 SMCLK
  USICTL0 &= ~USISWRST;                 // USI released for operation
  USISRL = P1IN;                        // init-load data

  P1DIR |= 0x04;                        // Reset Slave
  P1DIR &= ~0x04;
  for (i = 0xFFF; i > 0; i--);          // Time for slave to ready
  USICNT = 8;                           // init-load counter
  __bis_SR_register(LPM0_bits + GIE);   // Enter LPM0 w/ interrupt
}

// USI interrupt service routine
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=USI_VECTOR
__interrupt void universal_serial_interface(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(USI_VECTOR))) universal_serial_interface (void)
#else
#error Compiler not supported!
#endif
{
  if (0x10 & USISRL)
    P1OUT |= 0x01;
  else
    P1OUT &= ~0x01;
  USISRL = P1IN;
  USICNT = 8;                           // re-load counter
}

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