求助大哥解决说stm32printf重定向问题

杜文迪 · 发表于 2020-4-2 12:34:35

做串口打印实验的时候，按以下步骤将printf()函数重定向为串口，可是发现串口调试助手这里什么也没有，非常郁闷，有大哥能帮我解答一下这是为什么吗？
1、添加printf的头文件 #include <stdio.h>

2、重写int fputc(int ch, FILE *f)函数

int fputc(int ch, FILE *f);
函数
int fputc(int ch, FILE *f)
{
USART_SendData(USART1, (uint8_t) ch);
while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET)；
return ch;
}
3、修改一下选中Use MicroLIB Target——Code Generation——选中Use MicroLIB

这下面是串口程序
#include <stdio.h>
#include "stm32f10x.h"
#include "usart.h"

#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__ */

void USART1_Init(u16 baud)
{

GPIO_InitTypeDef GPIO_InitStructure;
   USART_InitTypeDef USART_InitStructure;
   NVIC_InitTypeDef NVIC_InitStructure;

   RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA, ENABLE);
   USART_DeInit(USART1);
   //USART1_TX PA.9
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; //PA.9
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure); //3õê¼»ˉPA9

//USART1_RX    PA.10
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);

//Usart1 NVIC ÅäÖÃ
/*
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
   NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;
   NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
   NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStructure);

  USART_InitStructure.USART_BaudRate = baud;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

  USART_Init(USART1, &USART_InitStructure);
  USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
  USART_Cmd(USART1, ENABLE);
}

PUTCHAR_PROTOTYPE
{
/* Place your implementation of fputc here */
/* e.g. write a character to the USART */
  USART_SendData(USART1, (uint8_t) ch);

  /* Ñ-»·μè′yÖ±μ½·￠Ëí½áêø*/
  while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET)
  {}

  return ch;
}