USB-IF Compliance Updates

Number of Updates: 5

Table of Contents
ID Updated Subject Reason Mandate Effective Date
150 March, 2022 USB Products Capable of Wireless Charging Must Demonstrate Capability Clarification of requirements surrounding wireless charging Required April, 2022

127 August, 2019 Discontinuing Backwards Compatibility Tree Backwards Compatibility Tree does not provide additional test coverage Required April, 2019

69 October, 2016 Suspend Current to be Measured on All USB Peripherals in the Powered state Measures the peripepheral's ability to drop to suspend current levels prior to reset. Required February, 2010

11 November, 2015 Interoperability Gold-tree Update Candidate Gold-tree Definition Required March, 2011

99 October, 2014 Demonstrated Interoperability on UHCI and OHCI Deprecated Conducting interoperability on UHCI and OHCI host controllers is no longer mandatory. Optional September, 2014

Interoperability Gold-tree Update
Mandate: Required
Effective Date: March, 2011

The USB-IF uses a tree of known, good, USB devices to verify interoperability and functionality of a USB device. This tree is referred to as the Gold-tree.

The gold-tree is supposed to consist of USB-IF certified consumer devices that are widely available in the market. Unfortunately, the shelf-life of consumer products is limited and some items become difficult to find as time goes by.   As a result, the USB-IF will no longer identify specific makes and models of products for the gold-tree.  The shelf life and availability of consumer products is just too short and is difficult to maintain.  Because there is nothing special about the peripherals and hubs, except being USB Certified, product classes and types are specified.

Test Procedures

The test procedures for using the candidate gold-tree may be used.  Please download the GoldSuite Test Procedure.

Devices that are both self-powered and bus-powered must be tested using bus-power.

Self-powered devices must be checked for bus powered operation.  Self-powered devices that enumerate on bus power must be tested as bus-powered.

All USB peripherals and hubs are required to enumerate on a SuperSpeed host controller and pass all applicable tests within USB30CV.

All USB peripherals, hubs, and hosts are required to enumerate on a SuperSpeed host controller and pass all applicable tests using the USB 3.1 interoperability test procedures.

Hubs and compound devices:

When testing hubs or compound devices, attach them to the highest operational tier level. Typically, that will be tier level 4. If the compound device contains another embedded hub, then attach to tier level 3.  Move gold tree devices on the branch to the exposed downstream ports on the hub or compound device.  If the hub under test is bus-powered, only low-powered peripherals, such as the mouse, should be attached to the bus-powered hub.
Hubs with no embedded devices:
   Run USB20CV chap 9 and 11 on the hub
   Run interoperability on the EHCI with 3.1 gold device(s) attached
Hubs with embedded devices (compound):
   Run USB20CV on the hub and on each embedded device
   Concurrently run interoperability on the EHCI on all embedded devices
Isochronous Devices:
   High-speed isochronous DUTs are simply added to the USB 3.1 tree and must operate concurrently with the hi-speed camera.

Vendors are encouraged to test their devices against a variety of hosts and peripherals and not to rely solely on the USB-IF Gold-tree for validation.

Please see the USB 2.0 Compliance Test Program for the tests that are required for USB 2.0 Certification.

Discontinuing Backwards Compatibility Tree
Mandate: Required
Effective Date: April, 2019

Effective immediately testing against the backwards compatibility interoperability tree is no longer required for compliance. The standard interoperability tree catches all failures found on the backwards compatibility tree.

USB Products Capable of Wireless Charging Must Demonstrate Capability
Mandate: Required
Effective Date: April, 2022

Much like how a monitor with a built in USB hub must demonstrate the ability to simultaneously operate the USB hub and display video, so must a USB Type-C device capable of wireless charging demonstrate wireless charging capability while interoperating in various states .This compliance update clarifies that USB developers, seeking certification of their wireless charging capable USB products, are required to provide devices that demonstrate the wireless charging capabilities of their product.

Suspend Current to be Measured on All USB Peripherals in the Powered state
Mandate: Required
Effective Date: February, 2010

Figure 9-1 in Section 9.1.1 of the USB 2.0 Specification identifies device states where suspend must be supported.  Peripherals are required to support the suspend state whenever VBus is powered, even if bus reset has not occurred.  The "Dead Battery" supend current test measures current consumed while the peripheral is in the "powered" state. 

The "Dead Battery" suspend current test procedure is a required compliance test for all upstream USB ports.  This procedure measures the ability of the peripheral to drop from unconfigured current to suspend current prior to bus reset.  The test procedure is identified at Charging#1.

It is common for a downstream port to provide power while suspended.  A powered suspend state is necessary for remote wakeup to function.  Also, a powered suspend state is becoming increasingly popular on PCs and hubs to enable USB battery charging, even if the PC is not operating.  Power is a limited resource and peripherals that do not have batteries (or have batteries but do not use USB to charge their batteries) must limit power consumption to suspend current levels.  Limiting current consumed to suspend levels allows any extra power to be diverted to adjacent downstream ports to be used for battery charging.  An exception is made for products with dead or weak batteries. Products with dead or weak batteries are allowed to draw up to 5 unit loads during the powered state suspend test. Refer to the connect timing ECN for more details on this exception.


Demonstrated Interoperability on UHCI and OHCI Deprecated
Mandate: Optional
Effective Date: September, 2014
Demonstration of interoperability on OHCI and UHCI is informational only and not required for the purposes of certification.

Device Framework tests using USB20CV and average current measurements are still mandatory compliance tests.

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