stm32 keil实现串口printf输出中文字符

添加如下代码，可以GNUC的方式实现

#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__ */

int main()

{

  while(1)

  {

  }

}

/**

  * @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 USART */

  USART_SendData(USART1, (uint8_t) ch);

  /* Loop until the end of transmission */

  while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET)

  {}

  return ch;

}

#ifdef  USE_FULL_ASSERT

/**

  * @brief  Reports the name of the source file and the source line number

  *         where the assert_param error has occurred.

  * @param  file: pointer to the source file name

  * @param  line: assert_param error line source number

  * @retval None

  */

void assert_failed(uint8_t* file, uint32_t line)

{ 

  /* User can add his own implementation to report the file name and line number,

     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  /* Infinite loop */

  while (1)

  {

  }

}

#endif