SPI_isBusy problem

I wrote a little code for the MSP432 which communicates with the CC1200 over the SPI.

 
The problem that I have is that the pin 4.1 which is the CSn pulls up too quickly. So I tried using SPI_isBusy to wait for the SPI to finish, but the problem remain. It seems that the SPI always returns NOT_BUSY. I watched the USBBUSY register for the ESUCI_B0 and it always stays low. Am I doing something wrong?

Here is the part of the code that doesn't work. I tried manually holding CSn low for a linger time and then everything works fine.

		///////////////////////////// READ FROM EXTENDED MEMORY
		MAP_GPIO_setOutputLowOnPin(GPIO_PORT_P4, GPIO_PIN1);
		while (MAP_GPIO_getInputPinValue(GPIO_PORT_P1, GPIO_PIN7));

		while (!(MAP_SPI_getInterruptStatus(EUSCI_B0_BASE,EUSCI_B_SPI_TRANSMIT_INTERRUPT)));
		MAP_SPI_transmitData(EUSCI_B0_BASE, 0xAF);

		while (!(MAP_SPI_getInterruptStatus(EUSCI_B0_BASE,EUSCI_B_SPI_TRANSMIT_INTERRUPT)));
		MAP_SPI_transmitData(EUSCI_B0_BASE, 0x73);

		while (!(MAP_SPI_getInterruptStatus(EUSCI_B0_BASE,EUSCI_B_SPI_TRANSMIT_INTERRUPT)));
		MAP_SPI_transmitData(EUSCI_B0_BASE, 0x00);

		while (SPI_isBusy(EUSCI_B0_BASE) == EUSCI_SPI_BUSY);
		MAP_GPIO_setOutputHighOnPin(GPIO_PORT_P4, GPIO_PIN1);