STM32 printf問題

STM32 printf問題
怎么老是出現idenfier "FILE is Undefined",問題出在哪啊？望指教，謝謝！
我程序代碼配置如下：
#include "stm32f10x.h"
#include "stm32_eval.h"
#include

#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(void)
{
SystemInit();
/* Enable GPIOA and USART1 clocks */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_USART1, ENABLE);

USART1_GPIO_Configuration();
USART1_Configuration();

printf("The is a example!" );

}


/*********************************配置USART1的GPIO口*************************************/
void USART1_GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
// Configure USART1_Tx as alternate function push-pull
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure);

// Configure USART1_Rx as input floating
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
/************************************配置串口1參數***********************************/

void USART1_Configuration(void)
{

USART_InitTypeDef USART_InitStructure;

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_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

USART_Init(USART1, &USART_InitStructure);

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);

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

return ch;
}
========================================

因printf()之類的函數，使用了半主機模式。使用標準庫會導致程序無法運行,以下是解決方法:

方法1.使用微庫,因為使用微庫的話,不會使用半主機模式.

方法2.仍然使用標準庫,在主程序添加下面代碼:

#pragma import(__use_no_semihosting)
_sys_exit(int x)
{
x = x;
}
struct __FILE
{
int handle;
/* Whatever you require here. If the only file you are using is */
/* standard output using printf() for debugging, no file handling */
/* is required. */
};
/* FILE is typedef’ d in stdio.h. */
FILE __stdout;

這個方法確實解決問題。

首先要加上這句：#include
然后加入以下代碼：
///////使用標準printf的串口字節發送重定義///////////
//第一步：
#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__ */
//第二步：
#pragma import(__use_no_semihosting)
_sys_exit(int x)
{
x = x;
}
struct __FILE
{
int handle;
/* Whatever you require here. If the only file you are using is */
/* standard output using printf() for debugging, no file handling */
/* is required. */
};
/* FILE is typedef’ d in stdio.h. */
FILE __stdout;
//第三步：
//默認使用COM1
/**
* @briefRetargets the C library printf function to the USART.
* @paramNone
* @retval None
*/
PUTCHAR_PROTOTYPE
{
/* Place your implementation of fputc here */
/* e.g. write a character to the USART */

/* Loop until the end of transmission */
while (USART_GetFlagStatus(USART_COM1, USART_FLAG_TC) == RESET)
{}
USART_SendData(USART_COM1, (uint8_t) ch);
return ch;
}
////////////////////////////////////////////////////