CCS/TMS320F28377S: SPI 3-wire Mode, SPISTE toggle

Hi, 

I'm drive  SPI 3-wire using TMS28377S.

1) When tested with the following code settings, does SPISTE automatically toggle after sending a 16-bit word( SpiSend(0x8001); )?

2) Is there any way to prevent this?

========================================================================

/* SPI initialization part */
void InitSpi(void)
{
    SpiaRegs.SPICCR.bit.SPISWRESET = 0;
    SpiaRegs.SPICCR.bit.CLKPOLARITY = 1;
    SpiaRegs.SPICCR.bit.SPICHAR = (16-1);    // 16-bit word
    SpiaRegs.SPICCR.bit.SPILBK = 0;

    // Enable master (0 == slave, 1 == master)
    // Enable transmission (Talk)
    // Clock phase (0 == normal, 1 == delayed)
    // SPI interrupts are disabled
    SpiaRegs.SPICTL.bit.MASTER_SLAVE = 1;
    SpiaRegs.SPICTL.bit.TALK = 1;
    SpiaRegs.SPICTL.bit.CLK_PHASE = 0;
    SpiaRegs.SPICTL.bit.SPIINTENA = 0;
    SpiaRegs.SPIPRI.bit.TRIWIRE = 1;

    // Set the baud rate
    SpiaRegs.SPIBRR.bit.SPI_BIT_RATE = SPI_BRR; // 500kHz

    // Set FREE bit
    // Halting on a breakpoint will not halt the SPI
    SpiaRegs.SPIPRI.bit.FREE = 1;

    // Release the SPI from reset
    SpiaRegs.SPICCR.bit.SPISWRESET = 1;
}


/* SPI Send Function part */
uint16_t SpiSend(uint16_t data)
{
	uint16_t Dummy;
	SpiaRegs.SPICTL.bit.TALK = 1;
	SpiaRegs.SPITXBUF = data;
	while(SpiaRegs.SPISTS.bit.INT_FLAG !=1) {}
	Dummy = SpiaRegs.SPIRXBUF;
	return Dummy;
}


/* Real data transmission part */ 
void TestDataSendFunc(void)
{
	SPI_LOAD_LOW();         // SPISTE Low
	SpiSend(0x8001);	// 1
	SpiSend(0x8001);	// 2
	SpiSend(0x8001);	// 3
	SpiSend(0x8001);	// 4
	SPI_LOAD_HIGH();        // SPISTE High
}

================================================================