USB Standard CDC Driver

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USB Standard CDC Driver

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danielg14
Contributor I

Hi everyone,

I have developed a simple USB virtual com port (CDC) for a K20 microcontroller. I am currently using my own inf driver file with my own PId/VId.

It works great and I am able to transmit and receive data with ease.

My question is, is there a Pid/Vid combination that will cause any computer to automatically recognize the device as a standard CDC device when it's first plugged in and thus install the appropriate device driver? (I don't want end users to have to manually acquire and install my driver file)

-Daniel

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mjbcswitzerland
Specialist V

Hi

If you use an interface association desriptor for CDC with the device class set for communication and control to values
0x02, 0x02, 0x00

Windows 10 will automaticall install usbser.sys (generic CDC on Windows) - See https://msdn.microsoft.com/en-gb/library/windows/hardware/dn707976%28v=vs.85%29.aspx

There are a few other tricks for Windows:

https://msdn.microsoft.com/en-us/library/windows/hardware/ff537430%28v=vs.85%29.aspx

https://msdn.microsoft.com/en-us/windows/hardware/gg463179.aspx

I know of no VID/PD combinations that are designed to control such things and generally you will need to have a valid VID for your company (or use a PID under Freescale's - which you can request through your sale's representative as log as your production is < 10k).

In some cases you can also instruct the user to chose a standard driver from a set that Windows keeps, but this is also messy since Windows will issue a warning that it can't confirm that it matches with the device and will recommend to not use it - but it works with RNDIS from experience (which is based on CDC) so you you may find one that does operate with some trial and error.

Most CDC users will supply their driver with the product or on their web site and get it signed (costs about $100 year I believe) so that there are no warnings that it coud be from an untrusted source.

Regards

Mark

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