實驗3：UART通信

通信雙方幀格式一致胸梆，通信雙方的波特率一致

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板子通過uart和pc 通信匿沛， pc 發(fā)‘a'，led2 亮 榛鼎， pc 發(fā)‘b'逃呼，led2 滅

查看原理圖， 從P4 找

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用CH340將USB信號轉換為UART信號
同時也可以將UART信號轉換為USB信號

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USB_RXD與RXD鏈接

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PC過來的信號最終鏈接到了stm32 U1_USART1_RX,U1_USART1_TX

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STM32F051K8處理器通過pa9,pa10通信

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3.2 UART串口函數(shù)

 HAL_StatusTypeDef HAL_UART_Transmit (UART_HandleTypeDef * huart, uint8_t *
pData, uint16_t Size, uint32_t Timeout)
通過阻塞方式發(fā)送SIZE個字節(jié)者娱，發(fā)送的數(shù)據在pData里面抡笼，發(fā)送超時TimeOut


HAL_StatusTypeDef HAL_UART_Transmit_IT (UART_HandleTypeDef * huart, uint8_t *
pData, uint16_t Size)
通過huart,以中斷方式發(fā)送size個字節(jié)，發(fā)送的數(shù)據在pData里面

HAL_StatusTypeDef HAL_UART_Receive (UART_HandleTypeDef * huart, uint8_t * pData,
uint16_t Size, uint32_t Timeout)
通過阻塞的方式接收size個字節(jié)黄鳍；
HAL_StatusTypeDef HAL_UART_Receive_IT (UART_HandleTypeDef * huart, uint8_t *
pData, uint16_t Size)
通過huart,以中斷的方式接收size個字節(jié)推姻。接收的數(shù)據在*pData里面

3.3. 代碼實現(xiàn)

#include "stdio.h"
#include "string.h"
int main(void)
{
  /* USER CODE BEGIN 1 */
     unsigned char rebuf[10]={0};

  /* 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();
  /* USER CODE BEGIN 2 */
    printf("after initalize all ......\r\n");//
    printf("pi=%f\r\n",3.1415926);
  /* USER CODE END 2 */

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

    /* USER CODE BEGIN 3 */
        HAL_UART_Receive(&huart1,rebuf,3,0xffffffff);
        
       printf("rebuf = %s\r\n",rebuf);
        
        if(strncmp((char*)rebuf,"123",3)==0)
        {
         HAL_GPIO_WritePin(GPIOB,GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2, GPIO_PIN_RESET);
    }
        else if(strncmp((char*)rebuf,"abc",3)==0)
        {
    HAL_GPIO_WritePin(GPIOB,GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2, GPIO_PIN_SET);
    }