Re: [Libusb-devel] USB VID/PID for open source projects

[Xiaofan C. <xia...@gm...>]

On Fri, Mar 25, 2011 at 9:11 AM, Peter Stuge <pe...@st...> wrote:
>> > What do you mean by different design? I think as long as
>> > the end function is the same, the VID/PID combination
>> > can be the same even if different MCU/MPU is used.
>>
>> As long as there is a fixed way for a given VID/PID to discover
>> the board sub type.
>
> Yes different boards should be identifiable somehow, and I think
> vidpid has advantages over any other field, in or out of the device
> descriptor. vidpid is usually always visible for user in some way,
> while other fields may not be.

It may well partly due to the difficulty to get a valid PID that companies
are using the same PID for different product and then differentiate
the product using strings in the descriptor or other methods.

The other reason may be WHQL. One example is the Amontec Jtagkey.
http://www.amontec.com/download/amontec-jtagkey-driver-d2xx-20091124.zip
This driver works with all Amontec JTAGkey dongles (Amontec JTAGkey /
JTAGkey Tiny / JTAGkey-2 / JTAGkey-2P / JTAGkey-2 Tiny, etc).
This driver is signed and certified for Windows WHQL 32bits and 64bits.

They use the same PID (sub-license from FTDI) for the different product.
I think the main reason may well be WHQL -- they probably do not want
to submit again.

-- 
Xiaofan