SPI_NSS的知识点解析，绝对实用

由手册可知：SPI_NSS片选引脚适用于从机是低电平片选的芯片。这样能选择硬件SPI片选，代码少两行使能和失能从机片选IO。

配置：



在main.c函数

/**
* @brief  The application entry point.
* @retval int
*/
int main(void)
{
        /* USER CODE BEGIN 1 */
        unsigned char ID[2] = {0};
        unsigned char cmd[4] = {READ_ID_CMD, 0x00, 0x00, 0x00};
        /* USER CODE END 1 */

        /* MCU Configuration--------------------------------------------------------*/

        /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
        HAL_Init();

        /* USER CODE BEGIN Init */

        /* USER CODE END Init */

        /* Configure the system clock */
        SystemClock_Config();

        /* USER CODE BEGIN SysInit */

        /* USER CODE END SysInit */

        /* Initialize all configured peripherals */
        MX_GPIO_Init();
        MX_USART1_UART_Init();
        MX_SPI5_Init();
        /* USER CODE BEGIN 2 */
        HAL_Delay(100);
        printf("sudarootrn");
        HAL_SPI_Transmit(&hspi5, cmd, 4, HAL_MAX_DELAY);
        HAL_SPI_Receive (&hspi5,  ID, 2, HAL_MAX_DELAY);
        printf("ID = 0x%02X%02Xrn", ID[0], ID[1]);
        /* USER CODE END 2 */

        /* Infinite loop */
        /* USER CODE BEGIN WHILE */
        while (1)
        {
                /* USER CODE END WHILE */

                /* USER CODE BEGIN 3 */
        }
        /* USER CODE END 3 */
}