October 10, 2000

1. October 10, 2000 1

2. October 10, 2000 2 USB 2.0 Test Modesand Their Application Jon LuekerIntel Corporation

3. October 10, 2000 3 Link Integrity Strategy Define necessary and sufficient set of specifications for cables, upstream-facingports, and downstream-facing ports Define reproducible tests which allow testingof each element in isolation Define required test modes which allow teststo be performed with standardized equipmentand techniques

4. October 10, 2000 4 Specifications for aHigh-Speed Transmitter Source impedance Clock frequency DC Levels into reference load Transmit eye pattern into reference load At pins of transceiver (guideline) At USB receptacle (if no captive cable) At end of cable (if cable is captive) Minimum allowable rise/fall time

5. October 10, 2000 5 Specifications for aHigh-Speed Receiver DC termination voltage and resistance Squelch threshold level Disconnect threshold level TDR (AC loading) limits Worst case eye patterns which mustbe recoverable At pins of transceiver (guideline) At USB receptacle (if no captive cable) At end of cable (if cable is captive)

6. October 10, 2000 6 Specifications forUSB Cable Maximum length and delay per meter(delay spec added in USB 1.1 ECN) Differential and common mode impedance (common mode spec added in ECN) Skew (tightened to 100 ps from 400 ps in ECN) Maximum allowable loss (added 200MHzand 400MHz points in ECN)

7. October 10, 2000 7 Test Modes High-speed capable devices/hubs must support test modes Test modes enable repeatable testing SetFeature(TEST_MODE) and SetPortFeature(PORT_TEST) requests provide standard means of entering mode Exit action is also standardized Upstream facing port – power cycle Downstream facing port – hub reset

8. October 10, 2000 8 Test Mode Test_SE0_NAK Port enters and remains in the high-speedidle state Regular actions, such as suspending,are inhibited Upstream-facing ports must respond to anyIN token packet with a NAK handshake(if CRC is correct)

9. October 10, 2000 9 Test Modes Test_Jand Test_K Port enters and remains in the high-speedJ or K state Regular actions, such as suspending,are inhibited

10. October 10, 2000 10 Test Mode Test_Packet Port repetitively transmits defined test packet Packet is designed to contain the full range of pattern frequencies and duty factors

11. October 10, 2000 11 Test Mode Test_Force_Enable Applies only to downstream–facing hub ports Required behaviors apply even if no deviceis attached Port must be enabled in high-speed mode Downstream packets must be repeated to the port

12. October 10, 2000 12 Example: Testing aSelf-Powered Device Testing Input Impedance and Termination Voltage Testing Output Levels Testing Transmit Waveforms Testing Receiver Sensitivity Testing Squelch Threshold

13. October 10, 2000 13 Example: Testing Input Impedance and Termination Voltage Attach DUT to USB 2.0 host controller Reset the device and then issue request to place device in Test_SE0_NAK mode Unplug cable from device and replace it with test cable/fixture Measure DC output voltage on each line Measure DC resistance on each line Perform differential TDR test on outputs

14. October 10, 2000 14 Example: TestingOutput Levels Attach DUT to USB 2.0 host controller Reset the device and then issue request to place device in Test_J mode Unplug cable from device and replace it with test cable/fixture Measure output voltages into 45 Ohm loadsto ground Repeat using Test_K

15. October 10, 2000 15 Eye Pattern Test Fixture

16. October 10, 2000 16 Three Transmitter Templates are Specified At the pins of the transmitter (Tightest specification, guideline only) At the connector nearest the transmitter (Only applies when there isn’t a captive cable) At the “far end” of a captive cable (Loosest specification, applies when there is a captive cable)

17. October 10, 2000 17 Example: TestingTransmit Waveforms Attach DUT to USB 2.0 host controller Reset the device and then issue request to place device in Test_Packet mode Unplug cable from device and replace it withhigh-frequency test cable/fixture Measure rise/fall time Capture single, complete occurrence of testpacket on a transient capture instrument Perform eye pattern analysis on waveform record

18. October 10, 2000 18 Example of a “Passing” Transmitter Waveform Note that higher level of overshoot is allowed in the unit interval following a transition

19. October 10, 2000 19 Narrow/Wide Symbols are Allowed as Long as They Conform to the Template

20. October 10, 2000 20 Failing Transmitter Waveform Waveform is required to transition monotonically through range defined by the minimumeye opening

21. October 10, 2000 21 Failing Transmitter Waveform Higher level of overshoot is only allowed in the unit interval following a transition

22. October 10, 2000 22 Three Receiver Templates are Specified At the pins of the receiver (Tightest specification, guideline only) At the connector nearest the receiver (Only applies when there isn’t a captive cable) At the “far end” of a captive cable (Loosest specification, applies when there is a captive cable) In compliance testing, worst case waveforms are generated with test equipment and applied through test fixture

23. October 10, 2000 23 Example: Testing Receiver Sensitivity and Squelch Threshold Attach DUT to USB 2.0 host controller Reset the device and then issue request to placedevice in Test_SE0_NAK mode Unplug cable from device and replace it with test cable/fixture Using data generator, apply IN token packet while varying amplitude, frequency, and injected jitter Using a differential high-impedance probe, monitor the cable to see under which conditions device responds with NAK handshake