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STM32F205 and USB virtual com port problem

Question asked by donev.georgi on Aug 13, 2013
Latest reply on Aug 20, 2013 by donev.georgi

 Hi all,
 I'm using STM32F205VGT,STM32_USB-Host-Device_Lib_V2.1.0 and virtual com port driver "VCP_V1.3.1_Setup_x64.exe". The PC works with Windows 7/64bits. When I start USB device the initialization of USB starts correct and everything works OK. I can see this in debug terminal:  

1)
  USB Init...
 USB OTG FS VCP Device
 USB device library started.
  USB Device [FS] Reset....
  USB Device [FS] Reset....
  VCP Interface configured

 Then I unplug USB cable and this message appears:

  USB Device in Suspend Mode.
 
  And USB enter in Suspend Mode. After that I plug USB cable again:

  USB Device in Suspend Mode.
  USB Device [FS] Reset....
  USB Device [FS] Reset....
  VCP Interface configured

 And everything works fine. But when I try to connect USB of another computer this strange situation appears:

2)
  USB Device in Suspend Mode.
  USB Device in Suspend Mode.
  USB Device in Suspend Mode.
  USB Device in Suspend Mode.
  USB Device in Suspend Mode.
  USB Device in Suspend Mode.
  USB Device [FS] Reset....
  USB Device in Suspend Mode.
  USB Device [FS] Reset....
  USB Device in Suspend Mode.
  USB Device [FS] Reset....
  USB Device in Suspend Mode.
  USB Device [FS] Reset....
  USB Device in Suspend Mode.
  USB Device [FS] Reset....
  USB Device in Suspend Mode.
  USB Device [FS] Reset....
  USB Device in Suspend Mode.
  USB Device [FS] Reset....
  USB Device in Suspend Mode.
  USB Device [FS] Reset....
  USB Device in Suspend Mode.

  And PC cannot find the usb device. I tried to connect USB device to different computers and in some cases USB work fine but sometimes it doesn't work and  situation 2 appears. I examined the USB code and noticed that in situattion 2 the program doesn't enter in function DCD_HandleSof_ISR(); so I suppose that because the function  is not called therefore USB device enters in Suspend mode again. But I cannot find out why it happens,in some cases SOF appers but in sometimes it doesn't.
Has anybody got any idea? Thanks!

 

 

 

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