TI-RTOS TM4C129ENCPDT SPI driver unexpected output

Hello. I am using newest TI-RTOS and am trying to send SPI initialization sequence to MCP3909 energy meter.  My code is based on the TI SPI example provided in the CCS. Basically I just changed the MasterTxBuffer and removed the code for RX (loopback).

The SPI seemingly works, I tried at 100kHz and 10MHz, but the output data does not match what I need to send.

For example:

int masterTxBuffer = 0b00000001; // 1

Results in this:

Another example:

int masterTxBuffer = 0b11111111; //255

Result:

int masterTxBuffer = 0b10100100; // 164 = MCP3909 init, output dual channel pre-filter

Result:

SPI example prints correct (expected) decimal value:

SPI initialized
SPI: Master: 164
SPI: Done

As you can see, neither output corresponds to data in masterTxBuffer.

Here is my SPI function, slightly modified from TI SPI loopback example:

Void MCPinitFxn (UArg arg0, UArg arg1)
{
    SPI_Handle masterSpi;
    SPI_Transaction masterTransaction;
    bool transferOK;

    /* Initialize SPI handle as default master */
    SPI_Params_init(&params2);
    params2.bitRate = 100000;
    params2.frameFormat = SPI_POL0_PHA0;
    params2.dataSize = 8;
    masterSpi = SPI_open(SPI3, &params2);
    if (masterSpi == NULL) {
        System_abort("Error initializing SPI\n");
    }
    else {
        System_printf("SPI initialized\n");
    }

    /* Initialize master SPI transaction structure */
    masterTransaction.count = SPI_MSG_LENGTH;
    masterTransaction.txBuf = (Ptr)masterTxBuffer;
    masterTransaction.rxBuf = (Ptr)masterRxBuffer;

    /* Initiate SPI transfer */
    transferOK = SPI_transfer(masterSpi, &masterTransaction);

    if(transferOK) {
        /* Print contents of master receive buffer */
        System_printf("SPI: Master: %d\n", masterTransaction.txBuf);
    }
    else {
        System_printf("SPI: Unsuccessful master SPI transfer");
    }

    /* Deinitialize SPI */
    SPI_close(masterSpi);

    System_printf("SPI: Done\n");
    System_flush();

}

What could be the problem?