一、串口实现printf

1.hal配置

2.重定向代码

/* USER CODE BEGIN Includes */
#include "stdio.h"
/* USER CODE END Includes */

int fputc(int ch, FILE *f)
{
   HAL_UART_Transmit(&huart1,(uint8_t*)&ch,1,5,0xffff);//20220113
	//串口重定向，执行任意长度字符发送到串口
//	HAL_UART_Transmit_IT(&huart1,(uint8_t*)&ch,1);
//	HAL_Delay(1);
	return 0;
}

int fgetc(FILE *f)
{
	uint8_t ch;
	//HAL_UART_Receive_IT(&huart1,(uint8_t*)&ch,1);//20220113
	HAL_UART_Receive(&huart1,(uint8_t*)&ch,1,5,0xffff);//20220113
	
	return ch;
}

二、串口2中断收发

配置同上

1.l轮循环方式发送

uint8_t uart3_txbuf[] = "UART3 Test\r\n";
 HAL_UART_Transmit(&huart3, uart3_txbuf,sizeof(uart3_txbuf),100);	

2.中断接收

初始化后先执行一次

HAL_UART_Receive_IT(&huart3, uart3_rxbuf, 1);

相关变量

#define  MAX_RECV_LENGTH  100  //定义接收缓冲区大小 

 uint8_t uart2_rxbuf[MAX_RECV_LENGTH];
 uint16_t uart2_cnt = 0;
 uint8_t uart3_rxbuf[MAX_RECV_LENGTH];
 uint16_t uart3_cnt = 0; 

添加回调函数

//接收到1字节数据，回调函数如下
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
  if(huart->Instance==USART2)
  {
	
	if(uart2_cnt<MAX_RECV_LENGTH){
        uart2_cnt++;   		
		HAL_UART_Receive_IT(&huart2,uart2_rxbuf+uart2_cnt,1);
		
	}
  } 
  else if(huart->Instance==USART3)
  {
	
   	if(uart3_cnt<MAX_RECV_LENGTH){ 
        uart3_cnt++;  		
		HAL_UART_Receive_IT(&huart3,uart3_rxbuf+uart3_cnt,1);
		
	}
  } 
// printf("resive data \r\n");
}

可通过超时判断一帧数据是否接收完成，完成后清空缓存 重启接
不能用HAL_UART_Receive_IT 重置 不生效遇到过坑。

		memset(uart3_rxbuf, 0, sizeof(uart3_rxbuf));
		uart3_cnt = 0;
		UART_Start_Receive_IT(&huart3,uart3_rxbuf+uart3_cnt,1); //不是HAL_UART_Receive_IT 

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原文链接：https://blog.csdn.net/qq_15174437/article/details/122746997