TM4C1294KCPDT SPI Interface Chip select issue

#define SPI_CLOCK_FREQUENCY		(250000)
#define SYSTEM_CLOCK_FREQUENCY	(120000000)

void ssi_initialize()
{
	uint32_t i;

	ssi_ss_gpio_initialize();
	
	// Enable the system clock gating
	ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI0);
	ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
	ROM_SysCtlDelay(25);

	// Pin type is set to alternate SSI function
	ROM_GPIOPinConfigure(GPIO_PA2_SSI0CLK);
	ROM_GPIOPinConfigure(GPIO_PA3_SSI0FSS);
	ROM_GPIOPinConfigure(GPIO_PA4_SSI0XDAT0);
	ROM_GPIOPinConfigure(GPIO_PA5_SSI0XDAT1);
	ROM_GPIOPinTypeSSI(GPIO_PORTA_BASE, (GPIO_PIN_2 | GPIO_PIN_3 | GPIO_PIN_4 | GPIO_PIN_5));
	
	// Enable the clock to the SSI
	ROM_SSIClockSourceSet(SSI0_BASE, SSI_CLOCK_SYSTEM);
	
	// CPOL = 1, CPHA = 1 Clock=160kHz
	ROM_SSIConfigSetExpClk(SSI0_BASE, SYSTEM_CLOCK_FREQUENCY, SSI_FRF_MOTO_MODE_3, SSI_MODE_MASTER, SPI_CLOCK_FREQUENCY, 8);

	// Enable the peripheral
	ROM_SSIEnable(SSI0_BASE);

	while(ROM_SSIDataGetNonBlocking(SSI0_BASE, &i))
	{
	}
}

/*
	Initialises the GPIO as an output for SS
*/
void ssi_ss_gpio_initialize()
{
		ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);
		ROM_GPIOPinTypeGPIOOutput(GPIO_PORTC_BASE, GPIO_PIN_5);
		ROM_GPIOPinWrite(GPIO_PORTC_BASE, GPIO_PIN_5, GPIO_PIN_5);
}