想在一个程序里用多个串口的printf，为什么不可以

只看该作者 · 2013-11-18 17:12

1.STM32F103库函数里面，想用printf 而不是USARTSendData，这样好吗？
2.我在网上搜了这么一段程序，确实可以，但是不知道为什么，USART2的printf打印了12次后就再也不出数字了，串口1可以？为什么啊？？

#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__ */

#define CMD_BUFFER_LEN 511

//u8  rev_stop = 0;    //接收停止标志
//u8  gps_flag = 0; //GPS处理标志
u8 gpgga_flag = 0;
u8 gprmc_flag = 0;
u8 gpgsv_flag = 0;
GPS_INFO GPS;

void USART2_printf (char *fmt, ...)
{
char buffer[CMD_BUFFER_LEN+1];  // CMD_BUFFER_LEN长度自己定义吧
u8 i = 0;

va_list arg_ptr;
va_start(arg_ptr, fmt);
vsnprintf(buffer, CMD_BUFFER_LEN+1, fmt, arg_ptr);
while ((i < CMD_BUFFER_LEN) && buffer)
{
      USART_ClearFlag(USART2,USART_FLAG_TC);
USART_SendData(USART2, (u8) buffer[i++]);
while (USART_GetFlagStatus(USART2, USART_FLAG_TC) == RESET);
}
va_end(arg_ptr);
}

int main()
{
char a ='c';int b = 0;
NVIC_Configuration();
USART1_Configuration();
USART2_Configuration();
USART3_Configuration();
UART4_Configuration();

printf("configure finshed\r\n");
USART2_printf("%c,%d\r\n",a,b );  //12次后不出现了为什么？

while(1)
{
if((gpgga_flag == 1) || (gprmc_flag == 1) || (gpgsv_flag == 1))
{

printf("latitude:%d.%d.%d_%c\r\n",GPS.latitude_Degree,GPS.latitude_Cent,GPS.latitude_Second,GPS.NS);
         printf("longitude:%d.%d.%d_%c\r\n",GPS.longitude_Degree,GPS.longitude_Cent,GPS.longitude_Second,GPS.EW);
      printf("speed:%f\r\n",GPS.speed);
      printf("direction:%f\r\n",GPS.direction);
printf("satellite_num:%d\r\n",GPS.satellite);
      printf("height_ground:%f\r\n",GPS.height_ground);
           printf("height_sea:%f\r\n",GPS.height_sea);
printf("Time :%d%d%d-%d%d%d\r\n",GPS.D.year,GPS.D.month,GPS.D.day,GPS.D.hour,GPS.D.minute,GPS.D.second);
gpgga_flag = 0;
gprmc_flag = 0;
gpgsv_flag = 0;
         USART_ITConfig(UART4,USART_IT_RXNE,ENABLE);  //开启USART2 接收中断

}
}
}
#if 1
#pragma import(__use_no_semihosting)
struct __FILE
{
int handle;
};
FILE __stdout;

_sys_exit(int x)
{
x = x;
}
#endif

/**
  * @brief  Retargets the C library printf function to the USART1.
  * @param  None
  * @retval None
  */
PUTCHAR_PROTOTYPE
{
  /* Place your implementation of fputc here */
  /* e.g. write a character to the USART */
  USART_ClearFlag(USART1,USART_FLAG_TC);
  USART_SendData(USART1, (uint8_t) ch);

  /* Loop until the end of transmission */
  while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET)
  {}

  return ch;
}