在两个传输之间禁用STM32H7上的SPI外围设备?

我还在做两个nuclear STM32H743板之间的SPI实验。

我在全双工模式下配置了SPI,启用了CRC,SPI频率为25MHz(这样从机可以毫无问题地传输)。

DSIZE为8位,FIFO阈值为4。

在主机端,我发送4个字节,然后等待从服务器发送5个字节。我知道我可以使用半双工或单工模式,但我想了解全双工模式下的情况。

volatile unsigned long *CR1 = (unsigned long *)0x40013000;
volatile unsigned long *CR2 = (unsigned long *)0x40013004;
volatile unsigned long *TXDR = (unsigned long *)0x40013020;
volatile unsigned long *RXDR = (unsigned long *)0x40013030;
volatile unsigned long *SR = (unsigned long *)0x40013014;
volatile unsigned long *IFCR = (unsigned long *)0x40013018;
volatile unsigned long *TXCRC = (unsigned long *)0x40013044;
volatile unsigned long *RXCRC = (unsigned long *)0x40013048;
volatile unsigned long *CFG2 = (unsigned long *)0x4001300C;

unsigned long SPI_TransmitCommandFullDuplex(uint32_t Data)
{
    // size of transfer (TSIZE)
    *CR2 = 4;

    /* Enable SPI peripheral */
    *CR1 |= SPI_CR1_SPE;

    /* Master transfer start */
    *CR1 |= SPI_CR1_CSTART;

    *TXDR = Data;

    while ( ((*SR) & SPI_FLAG_EOT)  == 0 );

    // clear flags
    *IFCR = 0xFFFFFFFF;

    // disable SPI
    *CR1 &= ~SPI_CR1_SPE;

    return 0;
}

void SPI_ReceiveResponseFullDuplex(uint8_t *pData)
{
    unsigned long temp;

    // size of transfer (TSIZE)
    *CR2 = 5;

    /* Enable SPI peripheral */
    *CR1 |= SPI_CR1_SPE;

    /* Master transfer start */
    *CR1 |= SPI_CR1_CSTART;

    *TXDR = 0;
    *((volatile uint8_t *)TXDR) = 0;

    while ( ((*SR) & SPI_FLAG_EOT)  == 0 );

    *((uint32_t *)pData) = *RXDR;
    *((uint8_t *)(pData+4)) = *((volatile uint8_t *)RXDR);

    // clear flags
    *IFCR = 0xFFFFFFFF;

    // disable SPI
    *CR1 &= ~SPI_CR1_SPE;

    return temp;
}

这两个函数都是在 main

然后我试图移除两个步骤之间的SPI禁用(即,我不清除并再次设置位SPE),结果我陷入了函数中 SPI_ReceiveResponseFullDuplex 在 while .

SPE位的行为在参考手册中不是很清楚。例如,在半双工模式下,必须禁用SPI才能改变通信方向。但是在fuill双工模式下什么都没有(或者我错过了)。