STM32USART串口调节与printf重定义

首先，printf重定义后可以直接使用printf函数从串口发送数据

在usart.c中添加代码：

#ifdef __GNUC__


  /* With GCC/RAISONANCE, 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__ */


/**


  * @brief  Retargets the C library printf function to the USART.


  * @param  None


  * @retval None


  */


PUTCHAR_PROTOTYPE


{


  /* Place your implementation of fputc here */


  /* e.g. write a character to the EVAL_COM1 and Loop until the end of transmission */


  HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1, 0xFFFF);


  return ch;

}

便可以在main中直接使用printf函数了

int main(void)
{
  HAL_Init();
  MX_GPIO_Init();
  MX_USART1_UART_Init();
  while (1)
  {

printf("\n\r 我是杨海鑫\n\r");
HAL_Delay(1000);
  }

}