USB-IF Compliance Updates

Number of Updates: 2

Table of Contents
ID Updated Subject Reason Mandate Effective Date
11 April, 2014 Interoperability Gold-tree Update Candidate Gold-tree Definition Required March, 2011

69 March, 2010 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

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.

Gold-tree Device List

Item Class Description Example Product Qty
USB Host System   Multicore processor
Certified USB EHCI with integrated UHCI
Certified USB xHCI
DELL XPS8700 (example) 1
EHCI / OHCI   PCI Host Adapter using certified USB EHCI with integrated OHCI Adaptec, model AUA 4000 PCI adapter
1
xHCI (SuperSpeed host adapter).
Necessary only if not native to motherboard.
  PCI Host Adapter using certified USB xHCI USB-IF SuperSpeed PDK
1

HS Hub
(Self-powered)

Hub Hi-speed hub.  Minimum of 4 exposed downstream ports Belkin F5U233 6
FS Hub
(bus-powered)
Hub Full-speed hub.  Minumum of 2 exposed downstream ports
(Likely to be a compound device)
Targus Numeric Keypad with 2-port Hub, model PAUK10U 1
USB mouse HID Low-speed using interrupt transport Microsoft Basic Optical Mouse 1
HS Mass Storage MSC Hi-speed using bulk transport Memorex TravelDrive model 32509051
PC Camera UVC Hi-speed using isochronous transport Logitech QuickCam Ultra Vision P/N: 961471-0403 1
average current draw test jig    Fixture to measure current consumed from VBus http://www.usb.org/developers/adapters/ 1
one meter (or shorter) USB cables   any listed on USB-IF Cables and Connectors Integrators List  

1

4.5 meter USB cable with mini B-plug   any listed on USB-IF Cables and Connectors Integrators List  

1

2 meter USB cable with micro USB B-plug   any listed on USB-IF Cables and Connectors Integrators List  

1

five meter USB cables   any listed on USB-IF Cables and Connectors Integrators List  

8

Test Attachment Points

Attachment Notes:

  • All hi-speed hubs are self-powered
  • On Hub HS5, position the gold-tree devices and the DUT as shown.  In other words, attach the DUT between ports that are occupied on the hub.  The device is not allowed to interfere with adjacent ports.
  • Low-power devices are to be tested on the bus-powered Hub FS1
  • The hub identified as FS2 is a hi-speed, self-powered hub.  This hub will operate at full-speed because it is downstream of a full-speed hub.
  • The purpose of FS2 is to test the operation of high-powered devices on the full-speed branch (FS1 is bus-powered and unable to support high-powered devices).
  • High-power devices are to be tested on the bus-powered Hub FS1 (enumeration only) and the self-powered Hub FS2
  • Five meter cable assemblies must be used between hubs and between the hi-speed tree and the host
  • For peripherals that do not use a captive cable, a standard detachable USB cable assembly of maximum length that is appropriate for the peripheral must be used. For example, if the peripheral implements a micro B-receptacle, then a 2 meter standard A-plug to micro B-plug cable assembly must be used. SuperSpeed cable assemblies are not allowed in USB 2.0 compliance testing.
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.

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 USBCV chap 9 and 11 on the hub
   Run interoperability with gold device(s) attached.
Hubs with embedded devices (compound):
   Run USBCV on the hub and on each embedded device
   Concurrently run interoperability run on all embedded devices
Isochronous Devices:
   High-speed isochronous DUTs are simply added to the 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.

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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 http://compliance.usb.org/index.asp?UpdateFile=Battery 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.

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