STM32F103RCT6学习之三:串口

1.串口基础

 2.串口发送

1）基本配置

 注意：实现串口通信功能需在keil中设置打开Use Micro LIB，才能通过串口助手观察到串口信息

2)编辑代码

int main(void)
{/* USER CODE BEGIN 1 *//* 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 *//* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */uint8_t msg[]="Hello World!\n";while (1){/* USER CODE END WHILE */HAL_UART_Transmit(&huart1,msg,sizeof(msg),HAL_MAX_DELAY);/* USER CODE BEGIN 3 */}/* USER CODE END 3 */
}

3)分析 ---关于重定向

huart1是一个串口句柄，定义在usart.c中

如果重定向printf或sprintf,只需要重定义fputc和fgetc()

#include<stdio.h>
int fputc(int ch,FILE *f){HAL_UART_Transmit(&huart1,(uint8_t*)&ch,1,0xffff);return ch;
}
int fgetc(FILE  *f){uint8_t ch;HAL_UART_Receive(&huart1,(uint8_t*)&ch,1,0xffff);return ch;
}

那么主函数可以如下实现：：

int main(void)
{/* USER CODE BEGIN 1 *//* 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 *//* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){/* USER CODE END WHILE */printf("Hello World\t\n");HAL_Delay(500);/* USER CODE BEGIN 3 */}/* USER CODE END 3 */
}

**吐槽一下，显示“%”只能用下面的方法

printf("%%");
printf("%c",'%');

3.串口接收与发送

1)进行基本配置

除了上述配置外，加入中断

2)编辑代码

触发中断时系统会调用定义于stm32f1xx_it.c的void USART1_IRQHandler(void)

可以看到该中断服务函数又调用 HAL_UART_IRQHandler(&huart1),该函数定义于stm32f1xx_hal_uart.c中：

在传输模式下，该函数调用 UART_Receive_IT(huart);该函数同样定义于stm32f1xx_hal_uart.c中，该函数调用可重定义函数 HAL_UART_RxCpltCallback(huart);并重定向printf及sprintf

#include<stdio.h>
int fputc(int ch,FILE *f){HAL_UART_Transmit(&huart1,(uint8_t*)&ch,1,0xffff);return ch;
}
int fgetc(FILE  *f){uint8_t ch;HAL_UART_Receive(&huart1,(uint8_t*)&ch,1,0xffff);return ch;
}
#define RX_BUFFER_SIZE 50
uint8_t rxBuffer[RX_BUFFER_SIZE];//发送缓冲区
uint8_t rxData; //单字节接收数据
uint8_t txBuffer[RX_BUFFER_SIZE+10];//发送还出去
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{if (huart->Instance == USART1) // 检查是否为 USART1{static uint16_t rxIndex = 0;// 保存接收到的字节到缓冲区if (rxIndex < RX_BUFFER_SIZE - 1)  //确保不会写入超过缓冲区边界的位置{rxBuffer[rxIndex++] = rxData;// 如果接收到换行符（表示消息结束）if (rxData == '\n'){rxBuffer[rxIndex] = '\0'; // 添加字符串结束符// 拼接前缀并发送数据sprintf((char *)txBuffer, "STM32 Received: %s", rxBuffer);printf("%s", txBuffer);rxIndex = 0; // 重置接收缓冲区索引}}// 继续接收下一个字节HAL_UART_Receive_IT(&huart1, &rxData, 1);}
}

{/* USER CODE BEGIN 1 *//* 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 */HAL_UART_Receive_IT(&huart1, &rxData, 1);  //开启接收中断   参数为串口句柄、数据存储地址、接收字节数/* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE *///uint8_t msg[]="Hello World!\t\n";printf("Hello World!\t\n");while (1){/* USER CODE END WHILE *//* USER CODE BEGIN 3 */}/* USER CODE END 3 */
}

 

3)分析

 HAL_UART_Receive_IT()很有趣？！不要忘了加！两处！