串口数据printf打印不了哪里错了

老菜鸟

#include "usart.h"
#include "stdio.h"
 
#if 1
#pragma import(__use_no_semihosting)             
//??????????                 
struct __FILE 
{ 
int handle; 
}; 

FILE __stdout;       
//??_sys_exit()??????????    
_sys_exit(int x) 
{ 
x = x; 
} 
//???fputc?? 
int fputc(int ch, FILE *f)
{
while((USART1->SR&0X40)==0);//????,??????   
USART1->DR = (u8) ch;      
return ch;
}
#endif
 
void Usart_Config(void)
{

NVIC_InitTypeDef NVIC_InitStructure;
 
GPIO_InitTypeDef GPIO_InitStructrue;
USART_InitTypeDef USART_InitStructure;
 





RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);
GPIO_PinAFConfig(GPIOA,GPIO_Pin_9,GPIO_AF_USART1);
GPIO_PinAFConfig(GPIOA,GPIO_Pin_10,GPIO_AF_USART1);
GPIO_InitStructrue.GPIO_Pin  = GPIO_Pin_9|GPIO_Pin_10;
  GPIO_InitStructrue.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructrue.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructrue.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructrue.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOA,&GPIO_InitStructrue);
USART_InitStructure.USART_BaudRate = 115200;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No ;
  USART_InitStructure.USART_Mode =USART_Mode_Rx | USART_Mode_Tx;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None; 
USART_Init(USART1,&USART_InitStructure);
//USART_ITConfig(USART1,USART_IT_RXNE, ENABLE);
//USART_ITConfig(USART1,USART_IT_TC, ENABLE);
USART_Cmd(USART1,ENABLE);
USART_ClearFlag(USART1, USART_FLAG_TC);
 //USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
 
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);
 

}
 #ifndef USART_H
#define USART_H
#include "stm32f4xx_conf.h"
 void Usart_Config(void);
 

#endif

正点原子

可以参考下我们开发板的例子。