stm32添加串口调试

#if 1
#pragma import(__use_no_semihosting)
//标准库需要的支持函数
struct __FILE
{
	int handle;
};
typedef struct __FILE FILE;
FILE __stdout;
//定义_sys_exit()以避免使用半主机模式
void _sys_exit(int x)
{
	x = x;
}
//重定义fputc函数
int fputc(int ch, FILE *f)
{
	while ((USART3->SR & USART_FLAG_TC) == 0); //循环发送,直到发送完毕: USART_FLAG_TC=0x40
	USART3->DR = (u8) ch;
	return ch;
}
#endif

void Init_USART3(void)
{
	u32 baud = USART_BAUDRATE;
	USART_InitTypeDef USART_InitStructure;
	GPIO_InitTypeDef GPIO_InitStructure;
		
	RCC_APB1PeriphClockCmd(RCC_APB1ENR_USART3EN | RCC_APB1Periph_USART3, ENABLE);
	GPIO_PinRemapConfig(GPIO_PartialRemap_USART3, ENABLE);   

	GPIO_InitStructure.GPIO_Pin 		= GPIO_Pin_11;
	GPIO_InitStructure.GPIO_Speed 	= GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode 		= GPIO_Mode_IN_FLOATING;    //输入脚
	GPIO_Init(GPIOC, &GPIO_InitStructure);

	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
	GPIO_Init(GPIOC, &GPIO_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(USART3, &USART_InitStructure);

	USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);
	USART_Cmd(USART3, ENABLE);	
}

#define DEBUG_OUT	//开启串口调试

#ifdef DEBUG_OUT
#define _MSG_DBG(...)	printf(__VA_ARGS__)
#else
#define _MSG_DBG(...)
#endif

int main(void)
{
  Init_USART3();
  _MSG_DBG("init ok \r\n");

  while(1) {}
}

///重定向c库函数printf到串口，重定向后可使用printf函数
int fputc(int ch, FILE *f)
{
	/* 发送一个字节数据到串口 */
	USART_SendData(DEBUG_USARTx, (uint8_t) ch);
	
	/* 等待发送完毕 */
	while (USART_GetFlagStatus(DEBUG_USARTx, USART_FLAG_TXE) == RESET);		

	return (ch);
}

///重定向c库函数scanf到串口，重写向后可使用scanf、getchar等函数
int fgetc(FILE *f)
{
	/* 等待串口输入数据 */
	while (USART_GetFlagStatus(DEBUG_USARTx, USART_FLAG_RXNE) == RESET);

	return (int)USART_ReceiveData(DEBUG_USARTx);
}

void USART3_PutChar(char ch)
{
	while ((USART3->SR & USART_FLAG_TC) == 0); //循环发送,直到发送完毕
	USART3->DR = (u8) ch;
}

#if defined(DEBUG_ENABLE)

#if DEBUG_OUTPUT==DEBUG_UART1
	void USART1_PutChar(char ch);
	#define PUT_CHART(c) USART1_PutChar(c)
#elif DEBUG_OUTPUT==DEBUG_UART2
	void USART2_PutChar(char ch);
	#define PUT_CHART(c) USART2_PutChar(c)
#elif DEBUG_OUTPUT==DEBUG_UART3
	void USART3_PutChar(char ch);
	#define PUT_CHART(c) USART3_PutChar(c)
#endif

static inline void BoardOutChar(char ch)
{
	PUT_CHART(ch);
}

int fputc(int c, FILE *f)
{
#if defined(DEBUG_ENABLE)
	BoardOutChar((char) c);
#endif
	return 0;
}

#define NO_DEBUG    0
#define DEBUG_UART1 1
#define DEBUG_UART2 2
#define DEBUG_UART3 3

#define DEBUG_ENABLE

#define DEBUG_OUTPUT DEBUG_UART3

#if DEBUG_OUTPUT!=NO_DEBUG && DEBUG_ENABLE 
#define _MSG_DBG(...)	printf(__VA_ARGS__)
#else
#define _MSG_DBG(...)
#endif