LM3S SSI读写CAT93C46,总是读到0.    // Enables a peripheral SSI0
    SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI0); 
 // Configures pin(s) for use by the SSI peripheral
 // PA2 SSI0CLK(SSCK)  PA4 SSI0RX(MISO) PA5 SSI0TX(MOSI)
    GPIOPinTypeSSI(GPIO_PORTA_BASE,
       (GPIO_PIN_2 | GPIO_PIN_4 | GPIO_PIN_5));      // Configure the SSI, 1MHZ
    SSIConfigSetExpClk(SSI0_BASE,    // Base
                                    //SysCtlClockGet()/4,  // SSIClk
                                   20000000,            // 5MHZ
                                   SSI_FRF_MOTO_MODE_0, // Protocol
                                   SSI_MODE_MASTER,     // Mode
                                  1000000,    // BitRate
                                  8           // DataWidth
                                );
 // Enables the synchronous serial interface
SSIEnable(SSI0_BASE);           // CAT93C46
 CS_EE = 1;  // if Transmit FIFO is empty
 do
 {
   SSI0Status = SSIIntStatus(SSI0_BASE, 0);
 }
 while((SSI0Status & 0x03) == 0x02);    // Puts a data element into the SSI transmit FIFO
 // Write Enable Instruction for CAT93C46
 SSIDataPut(SSI0_BASE, 0x98);
  SSIDataPut(SSI0_BASE, 0x41);
 SSIDataPut(SSI0_BASE, 0x55);  // if Transmit FIFO is empty
 do
 {
   SSI0Status = SSIIntStatus(SSI0_BASE, 0);
 }
 while((SSI0Status & 0x03) == 0x02);
 // Gets a data element from the SSI receive FIFO.
 SSIDataPut(SSI0_BASE, 0x81);
 SSIDataGet(SSI0_BASE, pulData++);  CS_EE = 0;     是什么原因啊？ 此帖出自小平头技术问答