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USB VCOM CDC support in VISTA

kelly2
Associate II
Posted on September 14, 2009 at 06:26

USB VCOM CDC support in VISTA

6 REPLIES 6
kelly2
Associate II
Posted on May 17, 2011 at 12:51

I have a problem getting my ST CDC drivers working in the vista world. I get enumeration on XP and every thing works ok. But I try to switch to Vista Home Premium (32-bit OS) and I get an error code 10 when I look at the device in the hardware device manager. So the port will not work. What can be done?

Kelly

16-32micros
Associate III
Posted on May 17, 2011 at 12:51

Hi,

Check this Link at Microsoft, Seems a known Issue with Vista Home:

http://forums.microsoft.com/msdn/ShowPost.aspx?PostID=1272951&SiteID=1

Cheers,

STOne-32.

trevor1
Associate II
Posted on May 17, 2011 at 12:51

Interesting link STOne-32.

Seems a fix may be possible by modifying the inf file. The CDC driver for STM32 gets installed by running ''VCPDriver_V1.1_Setup.exe'' which is downloaded from this site. The big question is what exactly is this exe doing? Is it just installing the inf file? If so can the inf file be made available separately so that we can edit it in order to try above mentioned fixes and also so that the id strings can be modified to suit out product names?

I have asked this question before without a response. Could someone at ST please comment on this?

Thanks

Trevor

kelly2
Associate II
Posted on May 17, 2011 at 12:52

From what I have observed, The executable provided by ST puts an INF file into the WINDOWS/INF (hidden on XP SP3) directory. But this INF doesn't do the job. I have edited it to match others of its kind that use usbser.sys as the root driver. The problem is that Vista's usbser.sys is not ENOUGH or not working with it. I have looked at the supposed Microchip working example. It also fails on Vista. So I am of the opinion that ST needs to revamp their Driver/USB VCOM example. Also, it appears that VISTA X64 will only take SIGNED kernal level drivers. (that was taken from the post from STOne-32) So if CDC is still going to be viable in 10 years, we are going to need more support.

trevor1
Associate II
Posted on May 17, 2011 at 12:52

I've just tried mine on Vista Home Premium (auto updates enabled) and it works. Up to now I've been using XP.

However, my customer's engineers report that it works very intermitantly (much less than 50% of the time) for them. They are using Windows XP. I cannot recreate this intermitnt behaviour which is very frustrating.

When it does not work for them a virtual com port is not created on Windows. Could it be something to do with how the driver was installed i.e. not cancelling the ''found new hardware'' wizard when prompted?

Anyone got any ideas?

Regards

Trevor

pcaha9
Associate
Posted on May 17, 2011 at 12:52

Is there an Update? I use Windows 7 (7100) and the Problem is the same as under Windows VISTA.

Philipp