The serial peripheral interface (SPI) port on the MSP430 should be configured as a 3-pin device where the chip select pin is controlled manually. The detailed pin configuration is found in hal_spi_rf_xx.h, where xx denotes which specific hardware is being compiled.

/* Transceiver SPI signal */
#define     RF_PORT_SEL            P3SEL
#define     RF_PORT_OUT            P3OUT
#define     RF_PORT_DIR            P3DIR
#define     RF_PORT_IN             P3IN
#define     RF_MOSI_PIN            BIT0
#define     RF_MISO_PIN            BIT1
#define     RF_SCLK_PIN            BIT2