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Diffstat (limited to 'protocol/vusb/usbdrv/USB-ID-FAQ.txt')
| -rw-r--r-- | protocol/vusb/usbdrv/USB-ID-FAQ.txt | 149 |
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diff --git a/protocol/vusb/usbdrv/USB-ID-FAQ.txt b/protocol/vusb/usbdrv/USB-ID-FAQ.txt deleted file mode 100644 index d1de8fb618..0000000000 --- a/protocol/vusb/usbdrv/USB-ID-FAQ.txt +++ /dev/null @@ -1,149 +0,0 @@ -Version 2009-08-22 - -========================== -WHY DO WE NEED THESE IDs? -========================== - -USB is more than a low level protocol for data transport. It also defines a -common set of requests which must be understood by all devices. And as part -of these common requests, the specification defines data structures, the -USB Descriptors, which are used to describe the properties of the device. - -From the perspective of an operating system, it is therefore possible to find -out basic properties of a device (such as e.g. the manufacturer and the name -of the device) without a device-specific driver. This is essential because -the operating system can choose a driver to load based on this information -(Plug-And-Play). - -Among the most important properties in the Device Descriptor are the USB -Vendor- and Product-ID. Both are 16 bit integers. The most simple form of -driver matching is based on these IDs. The driver announces the Vendor- and -Product-IDs of the devices it can handle and the operating system loads the -appropriate driver when the device is connected. - -It is obvious that this technique only works if the pair Vendor- plus -Product-ID is unique: Only devices which require the same driver can have the -same pair of IDs. - - -===================================================== -HOW DOES THE USB STANDARD ENSURE THAT IDs ARE UNIQUE? -===================================================== - -Since it is so important that USB IDs are unique, the USB Implementers Forum, -Inc. (usb.org) needs a way to enforce this legally. It is not forbidden by -law to build a device and assign it any random numbers as IDs. Usb.org -therefore needs an agreement to regulate the use of USB IDs. The agreement -binds only parties who agreed to it, of course. Everybody else is free to use -any numbers for their IDs. - -So how can usb.org ensure that every manufacturer of USB devices enters into -an agreement with them? They do it via trademark licensing. Usb.org has -registered the trademark "USB", all associated logos and related terms. If -you want to put an USB logo on your product or claim that it is USB -compliant, you must license these trademarks from usb.org. And this is where -you enter into an agreement. See the "USB-IF Trademark License Agreement and -Usage Guidelines for the USB-IF Logo" at -http://www.usb.org/developers/logo_license/. - -Licensing the USB trademarks requires that you buy a USB Vendor-ID from -usb.org (one-time fee of ca. 2,000 USD), that you become a member of usb.org -(yearly fee of ca. 4,000 USD) and that you meet all the technical -specifications from the USB spec. - -This means that most hobbyists and small companies will never be able to -become USB compliant, just because membership is so expensive. And you can't -be compliant with a driver based on V-USB anyway, because the AVR's port pins -don't meet the electrical specifications for USB. So, in principle, all -hobbyists and small companies are free to choose any random numbers for their -IDs. They have nothing to lose... - -There is one exception worth noting, though: If you use a sub-component which -implements USB, the vendor of the sub-components may guarantee USB -compliance. This might apply to some or all of FTDI's solutions. - - -======================================================================= -WHY SHOULD YOU OBTAIN USB IDs EVEN IF YOU DON'T LICENSE USB TRADEMARKS? -======================================================================= - -You have learned in the previous section that you are free to choose any -numbers for your IDs anyway. So why not do exactly this? There is still the -technical issue. If you choose IDs which are already in use by somebody else, -operating systems will load the wrong drivers and your device won't work. -Even if you choose IDs which are not currently in use, they may be in use in -the next version of the operating system or even after an automatic update. - -So what you need is a pair of Vendor- and Product-IDs for which you have the -guarantee that no USB compliant product uses them. This implies that no -operating system will ever ship with drivers responsible for these IDs. - - -============================================== -HOW DOES OBJECTIVE DEVELOPMENT HANDLE USB IDs? -============================================== - -Objective Development gives away pairs of USB-IDs with their V-USB licenses. -In order to ensure that these IDs are unique, Objective Development has an -agreement with the company/person who has bought the USB Vendor-ID from -usb.org. This agreement ensures that a range of USB Product-IDs is reserved -for assignment by Objective Development and that the owner of the Vendor-ID -won't give it to anybody else. - -This means that you have to trust three parties to ensure uniqueness of -your IDs: - - - Objective Development, that they don't give the same PID to more than - one person. - - The owner of the Vendor-ID that they don't assign PIDs from the range - assigned to Objective Development to anybody else. - - Usb.org that they don't assign the same Vendor-ID a second time. - - -================================== -WHO IS THE OWNER OF THE VENDOR-ID? -================================== - -Objective Development has obtained ranges of USB Product-IDs under two -Vendor-IDs: Under Vendor-ID 5824 from Wouter van Ooijen (Van Ooijen -Technische Informatica, www.voti.nl) and under Vendor-ID 8352 from Jason -Kotzin (Clay Logic, www.claylogic.com). Both VID owners have received their -Vendor-ID directly from usb.org. - - -========================================================================= -CAN I USE USB-IDs FROM OBJECTIVE DEVELOPMENT WITH OTHER DRIVERS/HARDWARE? -========================================================================= - -The short answer is: Yes. All you get is a guarantee that the IDs are never -assigned to anybody else. What more do you need? - - -============================ -WHAT ABOUT SHARED ID PAIRS? -============================ - -Objective Development has reserved some PID/VID pairs for shared use. You -have no guarantee of uniqueness for them, except that no USB compliant device -uses them. In order to avoid technical problems, we must ensure that all -devices with the same pair of IDs use the same driver on kernel level. For -details, see the file USB-IDs-for-free.txt. - - -====================================================== -I HAVE HEARD THAT SUB-LICENSING OF USB-IDs IS ILLEGAL? -====================================================== - -A 16 bit integer number cannot be protected by copyright laws. It is not -sufficiently complex. And since none of the parties involved entered into the -USB-IF Trademark License Agreement, we are not bound by this agreement. So -there is no reason why it should be illegal to sub-license USB-IDs. - - -============================================= -WHO IS LIABLE IF THERE ARE INCOMPATIBILITIES? -============================================= - -Objective Development disclaims all liabilities which might arise from the -assignment of IDs. If you guarantee product features to your customers -without proper disclaimer, YOU are liable for that. |