question about the "OpenCom()"

首先，当用USB转串口线连接好STM32开发板和PC后，此时STM32是正常工作的，当打开我用CVI编写的串口测试软件后，我点击“搜索串口”控件（里面就只有一个OpenCom(5,"")函数），此时发现STM32开发板出现非正常状态，就像一直在复位一样。但是并没有复位，因为RESET引脚是高电平状态。

我怀疑，是不是OpenCom()函数背后究竟做了些什么？

i have a problem.

i connect a stm32 board via a usb-rs232 line to my pc.

then i open the rs232 terminal, when i click the "rs232 port search" control(in it is a simple function,Opencom(5,"")Image may be NSFW.
Clik here to view.,the stm32 board become a reset-like status. 

if i closed the rs232 terminal, then the stm32 board become normal.