Download USB 2.0 Compliance Testing Measurement Data

Agilent Technologies
N5416A
Automated USB 2.0 Pre-Compliance
Test Solution
Technical Presentation
Today’s Schedule
 USB 2.0 Overview
 USB 2.0 Compliance Testing
 Examples of Compliance Tests
 Demo of the Agilent Solution
 Q&A
USB 2.0 Overview
USB Integrators’ Forum
 Created by
Compaq, HewlettPackard, Intel,
Lucent, Microsoft,
NEC and Philips
 The USB-IF
(www.usb.org) governs
the specification and
use of USB, and resolves
any issues that arise
USB 2.0 Overview
Data Rates
 The USB-IF combined all USB 1.1 and 2.0 speed
buses into the USB 2.0 specification
 USB 2.0 consists of 3 modes-Low-speed (LS)
Full-speed (FS)
High-speed (HS)
Data Rates
1.5 Mb/s
12 Mb/s
480 Mb/s
Rise Times
75ns – 300ns
4ns – 20ns
500ps
USB 2.0 Overview
Physical Characteristics
 Cables can be up to 5m long; hubs up to 5
levels deep
 Downstream data flows from PC to peripherals
 Upstream data flows from peripherals to PC
USB Cable
+ Shield
VBUS
D+
DGround
USB 2.0 Overview
Signal Levels
Signal Level Transfer
Full/Low Speed
3.3V, 12/1.5Mbps
High Speed
400mV, 480Mbps
Required bandwidth
BW = 0.35/Tr= ~1 GHz
(Tr = ~400 ps)
USB 2.0 Overview
Path Impedances
Characteristic measurements during mechanical test
(High/Full speed cables）

Characteristic Impedance
Differential
90Ω± 15%
Common Mode 30Ω± 30%

Cable Attenuation
5.8dB @ 400MHz

Propagation Delay
26ns

D+/D- Propagation Skew 100ps
USB 2.0 Overview
Transmission Modes
Full Speed and Low
Speed modes are
determined by the
location of the Rpu
resistor (on D+ or D-).
The bus starts in full speed
mode using the Rpu resistor
After Chirp Handshake, if high
speed mode is available, the
Rpu resistor is disconnected
and bus changes to high
speed mode.
USB 2.0 Overview
Full Speed Packet Makeup
Packet 1
SYNC
PID(SOF)
Frame No. CRC EOP
Packet 2
SYNC
Packet 3
PID(IN) ADDR ENDP CRC EOP
frame
SYNC PID(NAK) EOP
USB 2.0 Overview
High Speed Packet Makeup
Signal Amplitude
400mV
SYNC:
32(Minimum 12) bit
Idle : SE0
EOP re-definition:
NRZ 01111111 w/o
bit stuffing
(SOF EOP is 40 bit)
SYNC
PID(IN) ADDR ENDP CRC
EOP
Today’s Schedule
 USB 2.0 Overview
 USB 2.0 Compliance Testing
 Examples of Compliance Tests
 Demo of the Agilent Solution
 Conclusion
 Q&A
USB 2.0 Compliance Testing
 Involves a set of test
procedures (available from
www.usb.org) performed in a
specific order
 The USB 2.0 HS test procedure
(v1.0) has been available
since December 2001
 The USB-IF performs the official
compliance testing
USB 2.0 Compliance Testing
Device Framework (Chapter 9) Tests
USB Check last used at Jan. 2002 workshop
and obsolete in March 2002
USB CV is the replacement
USB 2.0 Compliance Testing
Interoperability Test
USB 2.0 Compliance Testing
Electrical Tests
Full/Low speed signal quality
In-rush current
Droop/Drop
Backdrive voltage
High speed test
FS/LS
HS
USB 2.0 Compliance Testing
Required Test Software
USB CV
HS Electrical Test Tool
Electrical Test Bed Computer Environment:
Pentium ® III class or equivalent processor
128MB or more system memory
Motherboard with PCI Rev. 2.2 expansion slots
Network adapter or modem adapter for internet access
Intel D815EEA motherboard
Windows 2000 or XP (English version)
USB 2.0 Compliance Testing
Full/Low Speed Tests
Signal quality
In-rush current
Droop/Drop
Backdrive voltage
USB 2.0 Compliance Testing
Full/Low Speed Signal Quality
USB Test Process
1. Connect Probe to Test Fixture
2. Connect device to Test Fixture
3. Select Proper Test in N5416A Script
4. Run Test
USB 2.0 Compliance Testing
Upstream
Host / System
Up
stream
Hub
USB
System
(PC)
HUB
Oscilloscope
HUB
HUB
Adjacent
Device
HUB
Devices
 In FS tests, connect D+ of the
adjacent device to scope ch 3
 Connect D+ to ch 2
 Connect D- to ch 1
HUB
DUT
SQiDD
5m cable
USB 2.0 Compliance Testing
Full/Low Downstream Setup
USB 2.0 Compliance Testing
Upstream Trigger Setup
The logic trigger
occurs when the
EOP is reached
and the Adjacent
device is idle
(Trigger Setup is
done
automatically)
USB 2.0 Compliance Testing
Measurement Data
Measurement
Setup & Result
automatic
USB 2.0 Compliance Testing
Full Speed Test Results Example
Signal eye:
*** eye failure! (14 data points violate
eye) ***
*** waiver granted. ***
EOP width: 170.2029ns EOP width passes
Consecutive jitter range: -1703.52ps to
2268.87ps
RMS jitter 576.53ps
Paired KJ jitter range: -584.58ps to 0.00ps,
*** jitter failure ***
*** waiver granted ***
USB 2.0 Compliance Testing
Understanding Full Speed Test Results
Measurement Items:
D+
Dcommon
mode voltage
crossover location
eye diagram ref.
eye violation
green
blue
purple
yellow
diamond
yellow
circle
red dots
USB 2.0 Compliance Testing
Inrush Current Test
Types of Devices Tested
Bus powered devices
Self-powered devices
Vbus
attach
>120µf
GND
<10µf
USB 2.0 Compliance Testing
Inrush Current Test
 Bus or self-powered
USB devices
 Protects upstream
devices from damage
 50.0 µC limit
Required Tests
・Overall result: fail!
・Inrush at 5.000V: 503μC
*** inrush failure! *** (at 5.000V, maximum compliant
inrush is 50μC)
USB 2.0 Compliance Testing
Droop/Drop
The HUB/Host Test: When a
adjacent device is
connected, the VBUS droop
voltage must be within
330mV
USB 2.0 Compliance Testing
Backdrive Voltage
Voltage measured on D+, D-,
and VBUS upon power-up
After enumeration, USB plug
is disconnected and voltage
is measured on D+, D-, and
VBUS
Both measured with 15 k
resistor to ground
Voltages must not exceed 0.4 V under any of these conditions
USB 2.0 Compliance High Speed Testing
Required Test Equipment
Scope BW >=2GHz
USB 2.0 Compliance Testing
High Speed Test
High Speed Signal Quality
Time Domain Reflectometry( TDR )
Reciever Sensitivity and Squelch
J and K Voltage
CHIRP
Packet Parameters
Suspend/Resume
USB 2.0 Compliance Testing
HS Electrical Test Tools
The test mode can be any of the following:
Test J
Test K
Test _SE0_NAK
Test Packet
Test Force Enable
USB 2.0 Compliance Testing
HS Signal Integrity
Test packet output
by HS Electrical Test
Tool
The signal is isolated
from the host by the
HS Test Fixture
Waveform is
measured through a
90 ohm differential
termination
Differential Probe
HS
Relay
90
Device
USB 2.0 Compliance Testing
Measuring High Speed Signal Quality
Test packet output
USB 2.0 Compliance Testing
HS Signal Quality Test Results
Required Tests
Overall result: pass!
Signal eye:
eye passes
EOP width: 7.98 bits
EOP width passes
Receivers: reliable operation on
tier 6
receivers pass
Measured signaling rate:
480.0641MHz
signal rate passes
USB 2.0 Compliance Testing
Device HS Signal Quality
EL_2
Data rate specification (480 Mb/s±0.05%)
EL_4
TP3 eye pattern requirement
EL_5
TP2 eye pattern requirement
(device with captive cable)
EL_6
10-90% differential rise/fall times
(longer than 500ps)
EL_7
Monotonic data transitions for high speed
drivers in the eye pattern template
USB 2.0 Compliance Testing
HS Packet Parameters
The device is controlled by the
Electrical Test Tool on the PC
The reply packet from the device
is received and evaluated for:
 Sync
 EOP
 Spacing between packets
USB 2.0 Compliance Testing
HS Packet Parameters
Sync Field : 32 bit
EOP : 8 bit
USB 2.0 Compliance Testing
CHIRP, SUSPEND/RESUME/RESET Timing
USB Test Fixture
Probe
Probe
90
Device
USB 2.0 Compliance Testing
CHIRP Test
Reset duration
CHIRP K Duration
HS termination
assertion
Device’s Chip
Latency
(2.5us <-> 3ms)
Device turns on
HS termination
Chirp KJKJKJ
(500us以内)
CHIRP K
(1ms <-> 7ms)
USB 2.0 Compliance Testing
CHIRP Test
Device’s Chip
Latency
(2.5us <-> 3ms)
Enable High Speed
Termination After Chirp
KJKJKJ (within 500us)
USB 2.0 Compliance Testing
Suspend Timing
Suspend : 3.000ms <-> 3.125ms
D+ Voltage > 2.7V
USB 2.0 Compliance Testing
Resume Timing
Resume : < 2 bit time
USB 2.0 Compliance Testing
Reset Timing
Device
CHIRP K
Reset : 3.1ms <-> 6ms
USB 2.0 Compliance Testing
Reset Timing
Reset from Suspend : 2.5us <-> 3.000ms
USB 2.0 Compliance Testing
High Speed Receiver Sensitivity
Pulse Generator
SMA
Device
HS Relay
In SE0_NAK test mode, pulse generator outputs IN token;
device must not respond to tokens <100mV and must respond
to tokens >150mV
USB 2.0 Compliance Testing
High Speed Receiver Sensitivity
Data generator
Packet
Device response
Packet
USB 2.0 Compliance Testing
High Speed Receiver Sensitivity
Note: A waiver may
be granted if the
receiver does not
indicate squelch at
+/-50mV of 150mV
differential amplitude
USB 2.0 Compliance Testing
Time Domain Reflectometry
Confirm the signal
is less than 10mV
TDR
 Use TDR to
measure impedance
of connector, circuit
board, and active
termination
SMA
HS Relay
DEVICE
USB 2.0 Compliance Testing
TDR Test Results
70Ω ≦ ZHSTHRU ≦ 110Ω
80Ω ≦ ZHSTERM ≦ 100Ω
Differential impedance
USB Connector
Termination impedance
Thru
impedance
D- odd impedance
D+ odd impedance
Today’s Schedule
 USB 2.0 Overview
 USB 2.0 Compliance Testing
 Examples of Compliance Tests
 Demo of the Agilent Solution
 Conclusion
 Q&A
Examples of Compliance Tests
Test Example 1: Impedances
The effects of source and termination
impedances
A(w） H(w)
ZS
±
R1(w)
T(w)
Z0
H(w)
R2(w) ZL
Unregulated output impedance of
a driver could cause significant
overshoot or undershoot
Examples of Compliance Tests
Test Example 2: Full Speed
*** Overall result: fail! ***
Signal eye:
*** eye failure! *** (33 data points violate eye)
Examples of Compliance Tests
Test Example 2: A Detailed Look
Coupling between D+ and D-
Examples of Compliance Tests
Cautions with USB 2.0 Measurements
Hub quality can affect full/low speed upstream
measurements
For identical measurements to those in compliance
tests, use Intel’s CHUB
For high speed signal quality measurements, take
care in handling low level signals. Be careful of:
①Adjusting the offset and performing calibration
②Effects of fixturing impedance on signal quality
③The bandwidth of the probe
Today’s Schedule
 USB 2.0 Overview
 USB 2.0 Compliance Testing
 Examples of Compliance Tests
 Demo of the Agilent Solution
 Conclusion
 Q&A
Today’s Schedule
 USB 2.0 Overview
 USB 2.0 Compliance Testing
 Examples of Compliance Tests
 Demo of the Agilent Solution
 Conclusion
 Q&A
Conclusion
Summary
Compliance testing is a requirement
Compliance testing involves framework layer
evaluation and physical layer evaluation
In physical layer evaluation, signal quality is
influenced by components, circuit layout,
and driver circuitry
An easy-to-use oscilloscope is an important factor
in efficiently performing compliance testing
Conclusion
Reference Material
Universal Serial Bus Specification Rev 2.0 (USB-IF)
USB-IF Signal Integrity Test Description (USB-IF)
USB Design by Example
(John Hyde, John Wiley & Sons INC)
Universal Serial Bus System Architecture
(Don Anderson, MINDSHARE INC)
USB 2.0 High Speed Electrical Test Procedure v1.0
Today’s Schedule
 USB 2.0 Overview
 USB 2.0 Compliance Testing
 Examples of Compliance Tests
 Demo of the Agilent Solution
 Conclusion
 Q&A