stm32 串口收发任意长度数据

main.c

UART_HandleTypeDef huart1;
uint8_t USART1_RX_BUF[200];     //接收缓冲,最大USART_REC_LEN个字节.
uint16_t USART1_RX_STA = 0;     //接收状态标记
uint8_t USART1_Count = 0;

int main(void)
{
	  while (1)
	  {
			  if(USART1_RX_STA == 1)
			  {
				  HAL_UART_Transmit(&huart1, (uint8_t*)USART1_RX_BUF, USART1_Count, 1000);	//发送接收到的数据
		
				  while(__HAL_UART_GET_FLAG(&huart1, UART_FLAG_TC) != SET);		//等待发送结束
		
				  USART1_RX_STA = 0;
				  USART1_Count = 0;
				  memset(USART1_RX_BUF, 0, sizeof(USART1_RX_BUF));
			  }	
	  }
}

static void MX_USART1_UART_Init(void)
{
		  huart1.Instance = USART1;
		  huart1.Init.BaudRate = 115200;
		  huart1.Init.WordLength = UART_WORDLENGTH_8B;
		  huart1.Init.StopBits = UART_STOPBITS_1;
		  huart1.Init.Parity = UART_PARITY_NONE;
		  huart1.Init.Mode = UART_MODE_TX_RX;
		  huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
		  huart1.Init.OverSampling = UART_OVERSAMPLING_16;
		  if (HAL_UART_Init(&huart1) != HAL_OK)
		  {
		    Error_Handler();
		  }
		
		  __HAL_UART_ENABLE_IT(&huart1, UART_IT_RXNE); //开启接收中断
		  HAL_NVIC_EnableIRQ(USART1_IRQn);					//使能USART1中断通道
		  HAL_NVIC_SetPriority(USART1_IRQn, 3, 3);				//抢占优先级3，子优先级3
		
		  __HAL_UART_ENABLE_IT(&huart1, UART_IT_IDLE);
}

stm32f1xx_it.c

extern uint8_t USART5_RX_BUF[200]; 
extern uint16_t USART5_RX_STA; 
extern uint8_t USART5_Count;

void USART1_IRQHandler(void)
{
  /* USER CODE BEGIN USART1_IRQn 0 */
	uint8_t clear = 0, Res;


	 if((__HAL_UART_GET_FLAG(&huart1, UART_FLAG_RXNE) != RESET))
	 {
		 HAL_GPIO_WritePin(GPIOA, GPIO_PIN_1, GPIO_PIN_RESET);

		 HAL_UART_Receive(&huart1, &Res, 1, 1000);
		 USART1_RX_BUF[USART1_Count++] = Res;
	 }
	 else if((__HAL_UART_GET_FLAG(&huart1, UART_FLAG_IDLE) != RESET))
	 {
		 HAL_GPIO_WritePin(GPIOA, GPIO_PIN_2, GPIO_PIN_RESET);
		 clear = huart1.Instance->SR;
		 clear = huart1.Instance->DR;
		 USART1_RX_STA = 1;
	 }

  /* USER CODE END USART1_IRQn 0 */
  HAL_UART_IRQHandler(&huart1);
  /* USER CODE BEGIN USART1_IRQn 1 */

  /* USER CODE END USART1_IRQn 1 */
}

注意！！！
stm32f103串口4收发数据要改变DIR引脚电平：高电平打开发送TX，低电平打开接收RX

若需要将printf()函数转向串口输出，可在main.c文件添加如下代码

#ifdef __GNUC__
/* With GCC, small printf (option LD Linker->Libraries->Small printf
   set to 'Yes') calls __io_putchar() */
#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
#else
#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
#endif /* __GNUC__ */


PUTCHAR_PROTOTYPE
{
    HAL_UART_Transmit(&huart1 , (uint8_t *)&ch, 1, 0xFFFF);
    return ch;
}

若要计算输出浮点型，则在project properties > C/C++ Build > Settings > Tool Settings (TAB) > MCU GCC Linker > Miscellaneous > other flag中添加 -u_printf_float