28379D SPI master 发送数据

最近在使用28379D作为SPI 主机与从机芯片通信时遇到一些问题，请大家赐教。

我将SPIA作为master通信，从机是一个集成了ADF4158芯片的模块，只需要基于SCK,MOSI与片选CS即可。因此在硬件设计上，我只将GPIO16(SPISIMOA)、GPIO18（***)分别与该模块的SIMO和CLK相连，另用一个GPIO作为从机的片选信号。

我目前存在的疑惑有：

（1）GPIO17和GPIO19都悬空，不知这样是否会影响SPI的正常工作？

（2）我没有采用FIFO模式，不知这个模式与普通SPI有何区别？

（3）在我只需要主机发送数据，而不需要读取从机返回的数据时，以下代码是否能够成功实现8bit数据TxData的传输？

uint8_t REF_SPI_ReadWriteByte(uint8_t TxData)
{
    uint8_t dummy = 0;

    // waiting for the complement of  previous character shifting
    while(SpiaRegs.SPISTS.bit.BUFFULL_FLAG == 1) { }

    SpiaRegs.***.bit.TALK = 1; // Enable Transmit path
    SpiaRegs.SPITXBUF = TxData; // Master transmits data


    while(SpiaRegs.SPISTS.bit.INT_FLAG !=1){}//Non-FIFO mode


    dummy = SpiaRegs.SPIRXBUF; // Clears junk data from itself bc it rx’d same data tx’d
    return dummy;

}

（4）实际的需求是需要向从机写32bit的指令，一共有七条指令需要写入，以下代码能否实现我想要的功能？（temp即为需要同一次写入的32bit指令，从机芯片要求在写入前将片选RADAR_SPI_TX_CS拉低，写完后再拉高）

static void WriteToADF4158(uint32_t* buff,uint32_t address)
{
   uint32_t temp;
   temp = *(buff + address);

   GPIO_WritePin(RADAR_SPI_TX_CS,0);//enable
   Delay_ms(20);


   REF_SPI_ReadWriteByte((uint8_t)(temp>>24));
   REF_SPI_ReadWriteByte((uint8_t)(temp>>16));
   REF_SPI_ReadWriteByte((uint8_t)(temp>>8));
   REF_SPI_ReadWriteByte((uint8_t)(temp));

   Delay_ms(40);
   GPIO_WritePin(RADAR_SPI_TX_CS,1);//disable

}

（5）在这些代码的配置下，从机的输出看起来就是噪声，感觉根本没有数据写入。由于DSP选用的是ZWT封装，SPI接口模块也无法用探针去测试SCK或者MOSI的波形，我该如何验证呢？

以下是我相关SPI的配置代码，其中SPI的速率设置为500kHz，满足从机的时钟需求：

void InitSpiaGpio()
{
   EALLOW;

    //
    // Enable internal pull-up for the selected pins
    //
    // Pull-ups can be enabled or disabled by the user.
    // This will enable the pullups for the specified pins.
    // Comment out other unwanted lines.
    //
    GpioCtrlRegs.GPAPUD.bit.GPIO16 = 0;  // Enable pull-up on GPIO16 (SPISIMOA)
//  GpioCtrlRegs.GPAPUD.bit.GPIO5 = 0;   // Enable pull-up on GPIO5 (SPISIMOA)
    GpioCtrlRegs.GPAPUD.bit.GPIO17 = 0;  // Enable pull-up on GPIO17 (SPISOMIA)
//  GpioCtrlRegs.GPAPUD.bit.GPIO3 = 0;   // Enable pull-up on GPIO3 (SPISOMIA)
    GpioCtrlRegs.GPAPUD.bit.GPIO18 = 0;  // Enable pull-up on GPIO18 (***)
//    GpioCtrlRegs.GPAPUD.bit.GPIO19 = 0;  // Enable pull-up on GPIO19 (SPISTEA)

    //
    // Set qualification for selected pins to asynch only
    //
    // This will select asynch (no qualification) for the selected pins.
    // Comment out other unwanted lines.
    //
    GpioCtrlRegs.GPAQSEL2.bit.GPIO16 = 3; // Asynch input GPIO16 (SPISIMOA)
//  GpioCtrlRegs.GPAQSEL1.bit.GPIO5 = 3;  // Asynch input GPIO5 (SPISIMOA)
    GpioCtrlRegs.GPAQSEL2.bit.GPIO17 = 3; // Asynch input GPIO17 (SPISOMIA)
//  GpioCtrlRegs.GPAQSEL1.bit.GPIO3 = 3;  // Asynch input GPIO3 (SPISOMIA)
    GpioCtrlRegs.GPAQSEL2.bit.GPIO18 = 3; // Asynch input GPIO18 (***)
//    GpioCtrlRegs.GPAQSEL2.bit.GPIO19 = 3; // Asynch input GPIO19 (SPISTEA)

    //
    //Configure SPI-A pins using GPIO regs
    //
    // This specifies which of the possible GPIO pins will be SPI functional
    // pins.
    // Comment out other unwanted lines.
    //
    GpioCtrlRegs.GPAMUX2.bit.GPIO16 = 1; // Configure GPIO16 as SPISIMOA
//  GpioCtrlRegs.GPAMUX1.bit.GPIO5 = 2;  // Configure GPIO5 as SPISIMOA
    GpioCtrlRegs.GPAMUX2.bit.GPIO17 = 1; // Configure GPIO17 as SPISOMIA
//  GpioCtrlRegs.GPAMUX1.bit.GPIO3 = 2;  // Configure GPIO3 as SPISOMIA
    GpioCtrlRegs.GPAMUX2.bit.GPIO18 = 1; // Configure GPIO18 as ***
//    GpioCtrlRegs.GPAMUX2.bit.GPIO19 = 1; // Configure GPIO19 as SPISTEA

    EDIS;
}

void InitSpia(void)
{
    // Initialize SPI-A

    // Set reset low before configuration changes
    // Clock polarity (0 == rising, 1 == falling)
    // 16-bit character
    // Enable loop-back
    SpiaRegs.***.bit.SPISWRESET = 0;
    SpiaRegs.***.bit.CLKPOLARITY = 0;
    SpiaRegs.***.bit.*** = (8-1);//(16-1)
    SpiaRegs.***.bit.SPILBK = 0;//1;loopback disable(0)

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

    // Set the baud rate
    SpiaRegs.SPIBRR.bit.SPI_BIT_RATE = SPI1_BRR;

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

    SpiaRegs.SPIPRI.bit.TRIWIRE = 0;
    SpiaRegs.SPIFFTX.bit.SPIFFENA = 0;//disable FIFO

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

希望大家能帮帮我，每个问题可能都很琐碎，错误也可能很基础，谢谢大家的不吝赐教！