TMS320F28027: 程序中使用串口打印数据到串口助手，故不不可避免使用到printf函数，问题如下：

//-------------------------------以下都为 标准 printf函数连接--------------------------------------------------------------
//#################################################
//-----------------------------------------------
//Printf 函数连接
//-----------------------------------------------
void open_uart_debug (void)
{
	int status=0;
	status = add_device("uart", _MSA, my_open, my_close, my_read, my_write, my_lseek, my_unlink, my_rename);
	if (status == 0) {
		freopen("uart:", "w", stdout);		// open uart and redirect stdout to UART
		setvbuf(stdout, NULL, _IONBF, 0); 	// disable buffering for stdout
	}
}

int my_open(const char *path, unsigned flags, int fno)
{
	//scia_fifo_init();
	//scia_echoback_init();
	path = path;
	flags = flags;
	fno = fno;
	return 0;
}

int my_close(int fno)
{
	fno =fno;
	return 0;
}

int my_read(int fno, char *buffer, unsigned count)
{
	fno = fno;
	buffer = buffer;
	count = count;
	return 0;
}

int my_write(int fno, const char *buffer, unsigned count)
{
	int i=0;
	fno = fno;

	while(count-- > 0) {
		scia_xmit(buffer[i++]);
	}
	return count;
}

off_t my_lseek(int fno, off_t offset, int origin)
{
	fno = fno; offset = offset; origin = origin;
	return 0;
}

int my_unlink(const char *path)
{
	path = path;
	return 0;
}

int my_rename(const char *old_name, const char *new_name)
{
	old_name = old_name;
	new_name = new_name;
	return 0;
}