Keysight N5990A-301 PCI
Express Link Training Suite
ser Guide
U
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WARNING
© Keysight Technologies 2017
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Manual Part Number
N5990-91101
Manual Edition
Edition 3.0, July 2017
Keysight Technologies Deutschland GmbH
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2 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Contents
1 Introduction
2 Software Installation and Update
3 Starting and Registering the Software
Overview of this guide 8
Document History 9
PCIe Link Training Suite - Overview 10
Software Update 12
Software Installation 13
Starting Registered Software 18
Software Registration 19
4 Test Instrument Setup
N4903B J-BERT Setup 22
Setup with De-Emphasis Box 23
Setup with CM Interference AWG 24
Setup with Power Switch 25
M8020A J-BERT Setup 26
Basic setup 27
Setup with Power Switch 28
Keysight N5990A-301 PCI Express Link Training Suite User Guide 3
Contents
5 Using the Software
Connecting to the Instruments 30
Instrument Connection for J-BERT N4903B 31
Instrument Connection for J-BERT M8020A 32
Main User Interface 35
Basics 37
Demo Mode 37
Applying 38
PCIe Physical Parameters 38
Link Training Pattern 39
Edit Training Parameters in Fixed Mode 40
Edit Training Parameters in Interactive Mode 41
Loop-back Pattern 45
Clock Tolerance Compensation 46
Error Detector 46
Link Training Results 47
Power Switch 49
Timing 50
Jitter/SSC 52
Interferences 53
Voltage Levels 54
De-Emphasis 55
Bit Error Rate Measurement 56
Sequencer 57
BERT Control 57
Saving and Loading Settings 58
Expert Mode 58
Exporting The Script 58
6 Troubleshooting
4 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Script Editing 59
Limitations 61
Startup Fails 64
Slow Response 65
Link Training Fails 66
Contents
Keysight N5990A-301 PCI Express Link Training Suite User Guide 5
Keysight N5990A-301 PCI Express Link Training Suite
User Guide
1 Introduction
Overview of this guide / 8
Document History / 9
PCIe Link Training Suite - Overview / 10
1 Introduction
Overview of this guide
This guide provides a detailed description of the N5990A PCIe Link
Training Suite.
8 Keysight N5990A - 301 PCI Express Link Training Suite User Guide
Document History
Introduction1
First Edition (May, 2015)The first edition of this guide describes the
functionality of the software version 1.0
Second Edition (Feb
ruary, 2017): The second edition of this guide
describes the functionality of the software version 1.40
Second Edition (July, 2017)The second edition of this guide describes the
functionality of the software version 2.0
Keysight N5990A - 301 PCI Express Link Training Suite User Guide 9
1 Introduction
PCIe Link Training Suite - Overview
The Keysight PCIe Link Training Suite (N5990A-301) is a flexible tool for
trouble- shooting and debugging. It controls the pattern sequencer of a
Keysight J-BERT (N4903B or M8020A), to bring the device under test into
the loop-back mode. Enabling the loop-back mode is usually a
prerequisite for receiver compliance testing.
The PCIe LTS complements the full Test Automation Software (Keysight
N5990A opt. 101 or 201, according to the configuration), which provides
automated physical layer compliance tests and device characterization.
The software runs on a standard Windows XP or Windows 7 PC and
controls the hardware test resources through appropriate interfaces such
as a LAN (Local Area Network).
10 Keysight N5990A - 301 PCI Express Link Training Suite User Guide
Keysight N5990A-301 PCI Express Link Training Suite
User Guide
2 Software Installation
and Update
Software Update / 12
Software Installation / 13
The PCIe Link Training Suite N5990A-301 runs on the PC that controls the
J-BERT. If N5990A-301 is already installed on the PC and is not to be
updated, proceed to the next chapter.
2 Software Installation and Update
Software Update
If you want to upgrade a previous version of the PCIe Link Training Suite,
uninstall it first from the PC and then continue with the software
installation.
12 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Software Installation
Software Installation and Update 2
Prior to installing N5990A-301, if not yet installed, the following software
has to be installed, items 1 through 3, in the order given below:
1. Microsoft Windows XP SP3 or higher.
2. Keysight VISA IO Library 16.3 or higher.
3. Microsoft.NET Framework redistributable 2.0.
If using an N4903B J-BERT, make sure it has firmware version 7.40 or
higher, installed. Then, perform the following steps:
• Execute the installer file “PCIeLinkTrainingSuiteInstaller” (see Figure 1).
• The second and third page of the installer wizard will show the software
license agreement (see Figure and Figure 3).
• Read it carefully and select the “I accept the terms of the License
Agreement” option.
• The install location window is displayed as shown in Figure 4.
•Click Browse to select the destination folder, in which the software will
be installed.
•Click Install.
Keysight N5990A-301 PCI Express Link Training Suite User Guide 13
Figure 1 Installer Wizard
2 Software Installation and Update
Figure 2 Installer License Agreement Window
Figure 3 Installer Additional License Agreement Window
14 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Software Installation and Update 2
Figure 4 Installer Location Window
Keysight N5990A-301 PCI Express Link Training Suite User Guide 15
Figure 5 Installation Complete Window
2 Software Installation and Update
Figure 6 Completing Setup Window
After installation, the PCIe Link Training Suite icon will be available on your
desktop (see Figure 7).
Figure 7 PCIe Link Training Suite Icon
16 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Keysight N5990A-301 PCI Express Link Training Suite
User Guide
3 Starting and
Registering the
Software
Starting Registered Software / 18
Software Registration / 19
3 Starting and Registering the Software
Starting Registered Software
Double click the PCIe Link Training Suite icon on your desktop or start the
software from the Start >Programs > BitifEye menu.
If you have already registered the software, it will start automatically. You
can then proceed to
Chapter 4, “Test Instrument Setup”.
18 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Software Registration
Starting and Registering the Software 3
If you start the software without a valid registration key, a window as
shown in Figure 8 will open.
To get a valid registration key, send an e-mail to licensing@bitifeye.com
with the following information:
• Customer name (such as company and department or university and
institute).
• 16-digit certificate number (XXXX-XXXX-XXXX-XXXX), supplied with
your license certificate.
• Site Code and MID from the startup license dialog.
The activation code will be provided within three working days of the mail
being received at the address indicated above.
Figure 8 Licensing Window
Keysight N5990A-301 PCI Express Link Training Suite User Guide 19
Keysight 5990A-301 PCI Express Link Training Suite
User Guide
4 Test Instrument Setup
N4903B J-BERT Setup / 22
M8020A J-BERT Setup / 26
Prior to using the PCIe Link Training Suite software for connecting
instruments, it is recommended that you set up the test instruments and
establish the required connections.
• Connect the instruments to the controller PC by LAN.
• Establish all required cable connections between the instruments and
the DUT (device under test).
• Switch on the PC and instruments.
• Start Keysight “IO (Input Output) VISA (Virtual Instrument Software
Architecture) Connection Expert” and check the connections for the
instruments.
• Set the correct IP addresses of the instruments.
There are two possible configurations:
4 Test Instrument Setup
N4903B J-BERT Setup
• An N4903B J-BERT is required
• If a J20 module is installed, it can be used to generate sinusoidal
interferences.
• If jitter and/or SSC is available, these parameters can be controlled.
• An N4916B de-emphasis signal converter can be used to generate deemphasized signals. The N4916B must be connected to the J-BERT via
USB.
• An N4880A reference clock multiplier can be used to multiply a
reference clock from a DUT, in order to use the DUT's clock for pattern
generation. The N4880A must be connected to the J-BERT via USB.
• An 81150A arbitrary waveform generator (AWG) can be used to
generate common-mode sinusoidal interference. If no AWG is
connected, interference is generated using the J-BERT’s J20 module, if
available.
• A NetIo230B Power Switch can be used to power cycle the DUT
automatically.
The following sections show connection diagrams for different DUT types
and data rate.
22 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Setup with De-Emphasis Box
Test Instrument Setup 4
Figure 9 Setup with De-Emphasis Box
• Connect two N9398C blocking capacitors to RF+DC and RF+DC of
Pick-Up Tees.
• Connect DATA OUT to DE-EMPHASIS DATA IN.
• Connect AUX CLK OUT to DE-EMPHASIS CLK IN using N4916-61620
matched cable pair.
• Connect P2 and P2 BAR of N4903B to Interference Input of Pick-Up
Tees.
• Connect DATA OUT and DATA OUT BAR of N4916B De-Emphasis Signal
Converter to RF and RF of Pick-Up Tees.
• Connect CLK OUT to ERROR DETECTOR CLK IN.
• Connect the N4903B Data Outputs to Rx+ and Rx- of test fixture.
• Connect Tx+ and Tx- of test fixture to N4903B Data Inputs.
• Connect the N4903B TRIG OUT and TRIG OUT BAR to the test fixture
reference clock input pins.
Keysight N5990A-301 PCI Express Link Training Suite User Guide 23
4 Test Instrument Setup
Setup with CM Interference AWG
Figure 10 Setup with CM Interference AWG
• Connect two N9398C blocking capacitors to RF+DC and RF+DC of
Pick-Up Tees.
• Connect DATA OUT to DE-EMPHASIS DATA IN.
• Connect AUX CLK OUT to DE-EMPHASIS CLK IN using N4916-61620
matched cable pair.
• Connect P2 and P2 BAR of N4903B to Interference Input of Pick-Up
Tees.
• Connect DATA OUT and DATA OUT BAR of N4916B De-Emphasis Signal
Converter to RF and RF of Pick-Up Tees.
• Connect DATA OUT and DATA OUT BAR of N4880A Pulse Function
Arbitrary Generator to P1 and P1 BAR of N4903B.
• Connect CLK OUT to ERROR DETECTOR CLK IN.
• Connect the N4903B Data Outputs to Rx+ and Rx- of test fixture.
• Connect Tx+ and Tx- of test fixture to N4903B Data Inputs.
• Connect the N4903B TRIG OUT and TRIG OUT BAR to the test fixture
reference clock input pins.
24 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Setup with Power Switch
Test Instrument Setup 4
Figure 11 Setup with Power Switch
• Connect two N9398C blocking capacitors to RF+DC and RF+DC of
Pick-Up Tees.
• Connect DATA OUT to DE-EMPHASIS DATA IN.
• Connect AUX CLK OUT to DE-EMPHASIS CLK IN using N4916-61620
matched cable pair.
• Connect P2 and P2 BAR of N4903B to Interference Input of Pick-Up
Tees.
• Connect DATA OUT and DATA OUT BAR of N4916B De-Emphasis Signal
Converter to RF and RF of Pick-Up Tees.
• Connect CLK OUT to ERROR DETECTOR CLK IN,
• Connect the N4903B Data Outputs to Rx+ and Rx- of test fixture.
• Connect Tx+ and Tx- of test fixture to N4903B Data Inputs.
• Connect the N4903B TRIG OUT and TRIG OUT BAR to the test fixture
reference clock input pins.
• Connect Channel IN1 of the Power Switch to the Power Supply.
Keysight N5990A-301 PCI Express Link Training Suite User Guide 25
4 Test Instrument Setup
M8020A J-BERT Setup
• An M8020A J-BERT is required. It internally generates de-emphasis
and all necessary distortions (interference) without any further
instruments.
• If an M8020A S02 option is installed, the Interactive Training
Method is available.
• A NetIo230B Power Switch can be used to power- cycle the DUT
automatically.
The following sections show the connection diagrams for different DUT
types and data rate.
26 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Basic setup
Test Instrument Setup 4
Figure 12 Basic Setup
• Mount the N9398C blocking capacitors to DATA OUT and DATA OUT
BAR of M8020A.
• Connect the N9398C blocking capacitors to Rx+ and Rx- of the test
fixture.
• Connect Tx+ and Tx- of the test fixture to M8020A Data Inputs.
• Connect the M8020A TRIG OUT and TRIG OUT BAR to the test fixture
reference clock input pins.
Keysight N5990A-301 PCI Express Link Training Suite User Guide 27
4 Test Instrument Setup
Setup with Power Switch
Figure 13 Setup with Power Switch
• Mount the N9398C blocking capacitors to DATA OUT and DATA OUT
BAR of M8020A.
• Connect the N9398C blocking capacitors to Rx+ and Rx- of the test
fixture.
• Connect Tx+ and Tx- of the test fixture to M8020A Data Inputs.
• Connect the M8020A TRIG OUT and TRIG OUT BAR to the test fixture
reference clock input pins.
• Connect Channel IN1 of the Power Switch to the Power Supply.
28 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Keysight N5990A-301 PCI Express Link Training Suite
User Guide
5 Using the Software
Connecting to the Instruments / 30
Main User Interface / 35
Script Editing / 59
5 Using the Software
Connecting to the Instruments
After the PCIe Link Training Suite has started, the software is in
“offline” mode. This means that the user input has no effect until
the software is connected to the instruments. Click
Figure 14) to open the Connection dialog. In the Connection dialog,
Connect (see
enter all parameters that are necessary to establish connections to
the Signal Generator and complementary instruments.
Figure 14 Main window (Instruments disconnected)
In the “Instrument Connection Dialog” window, select the BERT
configuration as either:
• J-BERT N4903B (see Figure 15).
• J-BERT M8020A (see Figure 16).
Thus, depending on the selection, there are two possible
instrument connections:
30 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Instrument Connection for J-BERT N4903B
• BERT
• Select J-BERT N4903B.
• Channels: The available channel is “1 Channel (Data only)”.
• Enter the J-BERT address of the N4903B.
• J-BERT Configuration
• If you have an 81150A AWG to generate common-mode.
interference, check the “CM Interference AWG” check-box and enter
its VISA address in the corresponding text-box.
• Select whether you want to use an N4916B de-emphasis signal
converter to generate the de-emphasis signal.
• Select whether you want to use an N4880A reference clock
multiplier or not.
• If you have a remote-controlled power switch, select Power Switch
and enter its address. The default address format is
“IP;Username;Password”. You must also select a channel number.
Using the Software 5
Figure 15 Instrument Connection Dialog for N4903B
Keysight N5990A-301 PCI Express Link Training Suite User Guide 31
5 Using the Software
Instrument Connection for J-BERT M8020A
• BERT
• Select J-BERT M8020A.
• Channels:. The available channel is “1 Channel”.
• Enter the J-BERT address of the M8020A J-BERT Configuration.
• M8020A Configuration
• If you have a remote-controlled power switch, select the “Power
Switch” check-box and enter its address. The default address format
is “IP;Username;Password”. You must also select a channel number.
Figure 16 Instrument Connection Dialog for M8020A
If you want to use calibration data from the Keysight N5990A
automated test solution, select the calibration data folder in the
“Calibration Files Directory” box.
32 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Using the Software 5
Once configuration settings are done, click Connect. If the
connections are successful, the “Initialize Instruments” button is
enabled (see
Figure 17). Click Initialize Instruments to reset and
initialize the instruments.
If you don't want to reset the instruments, click
Close. However,
clicking “Initialize Instruments” is recommended in order to set the
instruments to a well-known state.
Keysight N5990A-301 PCI Express Link Training Suite User Guide 33
Figure 17 Instruments Connection Window (Instruments Connected)
Note:
You can use instruments (N4903B, 81150A) connected via
Ethernet, USB, or GPIB. The instruments must already be
configured in the Keysight IO Expert so that they can be remotely
controlled using the PCI Express Link Training Suite. Refer to the
Keysight IO Libraries Suite Quick Start Guide for instructions on
connecting the instruments to your PC for the first time. As soon as
5 Using the Software
this is done, you can find out the VISA address of an instrument by
selecting it in the Instruments list in the Keysight IO Expert. Note
that socket connections are not supported.
In order to use an N4916B de-emphasis signal converter, it must
be connected to the rear USB port of the N4903B J-BERT. Refer to
the N4916B Getting Started Guide when connecting an N4916B
the first time. Apply the same procedure for connecting the
N4880A reference clock multiplier.
34 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Main User Interface
Using the Software 5
After successful connection to the instruments, the main window is
displayed as shown in
Figure 18. This window is split into two major
parts:
The left part of the window displays PCIe specific parameters:
• PCIe spec version and DUT type
• The training sequence and loop-back pattern.
• PCIe specific presets.
• The right part of the window displays common J-BERT parameters:
• Data rate and clock generation.
• Voltage levels.
• De-emphasis.
• Jitter injection and interferences.
• Bit error rate measurement.
• BERT control.
Keysight N5990A-301 PCI Express Link Training Suite User Guide 35
5 Using the Software
Figure 18 PCIe Link Training Suite Main Window
36 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Basics
Using the Software 5
The basic operation of the PCIe Link Training Suite would be as
follows:
• Select a PCIe revision.
• Select a loop-back pattern.
• Apply settings to instruments and train the DUT into loop-back.
Now, you can adjust the instrument settings to debug the DUT, for
example, reduce the differential amplitude until bit errors are
observed or deviate the data rate to test the DUT's margins.
One of the main features of the PCIe Link Training Suite is to
modify the training sequence and the loop-back pattern. You can
let the PCIe Link Training Suite generate the sequences and
patterns automatically, or you can fine-tune the sequence and
patterns using a simple macro language.
Two terms repeated quite often are “sequence” and “pattern”. A
pattern is a stream of bits that is sent out by the BERT. In order to
be more flexible, the entire bit stream is divided into multiple
patterns, which are then processed by a sequencer. The sequencer
can loop patterns and step from one pattern to another. In this
way, it is possible to generate very long data streams with only
short patterns, which fit perfectly into the instrument's limited
memory.
Caution
Since the PCIe Link Training Suite is mainly intended for debugging
and troubleshooting, the parameters are not constrained to the
compliance values. Therefore, you must take care not to increase
critical parameters beyond the ratings of the DUT. Also, note that
the parameters you apply must be calibrated with the
corresponding instrument; Typically, they are not calibrated
according to your specific setup.
Demo Mode
When you close the connection dialog without connecting to
instruments, you enter the
Keysight N5990A-301 PCI Express Link Training Suite User Guide 37
Demo Mode.
5 Using the Software
Applying
The Demo Mode is intended for demonstration purposes, where no
actual hardware is available. Most functions will be available, but
no instrument will be affected.
When changing any parameter in the user interface, click Apply in
the bottom left corner of the main window for the changes to take
effect on the instruments.This applies all parameters at once.
Pressing
menu command
F6 on your keyboard has the same effect, as using the
Apply under the “Instruments” menu.
Each group box and window has a dedicated “Apply” button, which
only applies the parameters contained in that group or window.
There is also the menu command
“Apply Pattern Only” to apply just
the pattern while all other parameters remain unchanged. You can
find this command under the “Instruments” menu. Alternatively,
you can also press
“Apply” button while holding the
Shift+F6 on your keyboard, or click the main
Shift-key.
Track bars (or sliders) are a special case. For example, there is a
track bar in the “Voltage Levels” group box. When you move a
track bar, the affected parameter is immediately applied to the
hardware.
PCIe Physical Parameters
The corresponding controls are shown in Figure 19.
To test a PCIe DUT, you must define the PCIe specification revision and a
DUT type. These parameters affect the available settings and the way
calibration data is handled. For PCIe ASIC tests, you will also have to
select the calibration channel.
38 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Figure 19 PCIe Physical Parameter Settings
Link Training Pattern
Using the Software 5
When you change one of these settings, your instruments will
automatically be re-configured.
When the de-emphasis signal converter is connected, or when the
PCIe specification 3.0 or 4.0 is used, the current preset is also
shown. The
Preset button allows a preset to be selected from a list.
The selected preset is applied to the de-emphasis parameters on
the right side of the main window, and to the encoded preset hint
in the “Loop-back Pattern” box. When the de-emphasis levels on
the right side of the main window are changed, the corresponding
preset is shown in the
PCIe Physical Parameters panel.
The link training sequence is supposed to train the DUT into
loop-back. By default, it is generated automatically. However, you
have the option to parametrize the sequence to adjust it to the
DUT's needs.
Figure 20 Link Training Pattern Settings
There are two training modes: Fixed and Interactive.
In Fixed mode, the training pattern is defined by several blocks, following
the standard sequence described in the CTS.
Keysight N5990A-301 PCI Express Link Training Suite User Guide 39
5 Using the Software
The Interactive Mode is a feature available only for M8020A J-BERT. The
training sequence consists of three blocks -“Link Down”, a “Wait” block,
and “Link Up”. The loop-back training is managed by the M8020A J-BERT
internally. It can run the link equalization phase to optimize the
performance of communication.
Edit Training Parameters in Fixed Mode
If you click “Edit Training Parameters” (Figure 20) and Fixed Mode is
selected by default, you can adjust the number of packets
transmitted for every stage of the link training (
The “Initial delay” is a sequence of zeros transmitted before the link
training. By default, you must start the link training by exiting this
block via the “Manual Trigger” button (on the main window).
However, you can specify a time span instead.
The
Add EIEOS check-box allows some EIEOS (Exit From Electrical
Idle Ordered Sets), to be inserted before the loop-back pattern
starts. This is not required by the CTS, but might be helpful for
some DUTs. Every 32nd TS1 ordered set will be replaced by an
EIEOS. This number is fixed in order to match the J-BERT's pattern
granularity.
Figure 21).
40 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Using the Software 5
Figure 21 Sequence to Loop-back Mode
All other parameters reflect the standard sequence described in
the CTS. Note that “Min. initial TS1 count” and “Min. TS1 count
before Loop-back” are only arbitrary numbers. The actual number
of transmitted ordered sets might be slightly different so that they
match the J-BERT pattern granularity.
There are two presets, which can be selected using the “Preset”
button. Trying both preset options can be helpful for debugging.
“Optimized Parameters” is used as default, since it works with most
DUTs. “CTS Parameters” represents the link training procedure
recommended by CTS. However, this link training procedure might
not work with every DUT.
Edit Training Parameters in Interactive Mode
In interactive mode, click Edit Training Parameters (Figure 20) to adjust
some link training parameters (Figure 22).
Keysight N5990A-301 PCI Express Link Training Suite User Guide 41
5 Using the Software
Select DUT Type in PCIe Physical Parameters and Lane Number in
Encoding Lane Number on the main window.
The “Link Number” is the number of the link encoded in the
TS1/TS2 Training Ordered Sets.
For “Link EQ”, there are three options:
Bypass: No equalization training is done and the equalization
preset selected from “PCIe Physical Parameters” is used for the
whole link training and later in loop-back mode.
Preset Only: Only presets P0 to P9 can be requested from the DUT
during equalization training.
Full: Any combination of pre-shoot and de-emphasis can be
requested by the DUT during equalization training,
The Speed Change Control specifies whether the speed change to
Gen3 (that is, 8 Gbps), or Gen4 (that is, 16 Gbps), will be initiated
by the DUT or by the BERT during link training. It is only used when
the BERT operates as a downstream device. If not specified, DUT
will initiate the speed change and will also request the BERT for the
same. This option is only used when the DUT type is System Board
The “Generator Start Preset” is the start preset for the link training
in the M8020A output. On the main window, select
Preset
in PCIe Physical Parameters.
Equalization
42 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Using the Software 5
Figure 22 Interactive Link Training Parameters
The “DUT Rx Preset” Hint is the preset value that the M8020A sends to the
DUT as a hint for the Rx Equalization value.
The “DUT Tx Initial Preset” is the preset that the DUT must use at the start
of equalization training.
The “DUT Target Preset” is the preset that the DUT must use to send out
data after Link Training. If the Use cursors option is unchecked, you must
select the target preset in Encoded DUT Preset Request on the main
window. If the Use cursors option is checked, you can define the target
preset with the options Pre-Cursor, Main Cursor and Post-Cursor, as
shown in Figure 23.
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5 Using the Software
Figure 23 DUT Tx Target Preset with cursors
The option “Encoded Lane Number“ (on the main window), lets you
define the lane number that is encoded in the Training Pattern. The
default value is “Lane 0". To run link training on another physical
port of the DUT, connect that port to the J-BERT, while retaining
that lane number as
Lane 0. However, some DUTs require that the
lane number must be set to the corresponding physical port
number.
The option
Encoded DUT Preset Request lets you define the
equalization preset that is requested for the DUT.
The option “Use Gen3 EIEOS” is available for Gen4. When a Gen4
DUT is implemented against PCIe4 spec revision 0.5, it needs Gen3
EIEOS for 16GT/s and you must select this option. If it is
implemented against PCIe4 spec revision 0.7 or higher, it needs
Gen4 EIEOS for 16GT/s.
44 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Loop-back Pattern
Using the Software 5
The pattern that is continuously transmitted in Loop-back Mode can
be defined in the
Loop-back Pattern box, as shown in Figure 24. You
can select either PCIe Compliance Pattern, PCIeModified
Compliance Pattern, or a custom pattern file.
Figure 24 Loop-back Pattern Settings
In the simplest case, a custom pattern file can be a text-file containing
only hexadecimal data.
Note
The binary data represented by the custom pattern file must have a 512bit granularity for N4903B and 80-bit granularity for M8020A, otherwise
the pattern cannot be loaded into the generator's pattern memory. The
syntax of the selected file is automatically verified before the file can be
used. For details about the syntax and custom pattern files that can be
used, refer to the PCI Express Link TrainingSuite Language Guide.
When the Compliance Pattern is used in PCIeGen3 or Gen4, the
generator's equalization preset hint is also encoded in the pattern.You can
manually change the encoded value.
Keysight N5990A-301 PCI Express Link Training Suite User Guide 45
5 Using the Software
Clock Tolerance Compensation
In this group box, you can select how SKP ordered sets are inserted
into the training and loop-back patterns. By default, no extra SKP
ordered sets are generated (except at points where the PCI Express
specification explicitly requires them, for example, in the Gen3
modified compliance pattern).
Figure 25 Clock Tolerance Compensation Setting
When the DUT has its own reference clock, and no SSC is used
(SRNS - Separate Reference Clocks with No SSC), SKP ordered
sets must be inserted at an interval defined in the PCI Express
specification. When the DUT has its own reference clock, and SSC
is used on both the generator and the DUT side (SRIS - Separate
Reference Clocks with Independent SSC), SKP ordered sets must
be inserted at even shorter intervals.
Changing the “SKP Ordered Set Insertion” option (
Figure 25) defines
how often SKP ordered sets are inserted. Note that the gap
between two SKP ordered sets might be shorter than that required
by the specification, in order to fit the pattern into the J-BERT's
pattern memory.
Note that when a custom loop-back pattern is used, there are no
SKP ordered sets inserted into the custom pattern.
Error Detector
By default, the J-BERT error detector compares all bits from the
DUT with the loop-back pattern. With the option, ”Filter SKP OS”
(which is Unchecked by default) selected, SKP ordered sets can be
excluded from bit comparison.
46 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Using the Software 5
Figure 26 Error Detector Settings
This option (Figure 26) is usually required when the DUT uses its own
reference clock.
Link Training Results
This section contains the result of the Interactive Training Mode
(
Figure 27).
Figure 27 Link Training Results
If you click “Final Preset”, the Final Preset dialog appears (Figure 28),
which displays the final Preshoot, De-Emphasis and Preset after training.
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5 Using the Software
Figure 28 Final Preset Dialog
Clicking “Training Log” opens the Interactive Link Training Log
window that presents a detailed log of the whole training process
(
Figure 29).
48 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Using the Software 5
Power Switch
Figure 29 Final Preset Dialog
If you select Power Switch in the Instrument Connection dialog, the
Power Switch section is displayed on the main window (Figure 30).
Use this feature for the DUT’s power cycle, that is, to switch the
power Off or On.
Figure 30 Power Switch
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5 Using the Software
Timing
Click “TIming Setup” (see Figure 31), to open the Timing Setup window, as
shown in
Figure 31 Timing Section
Figure 32.
Here, you can define the Data Rate and add some Deviation to it. The
Reference Clock can also be modified, but note that the valid range
and granularity is restricted by the J-BERT hardware.
By default, the generator uses an internal clock source, or an
External Clock Multiplier (N4880A) for system board tests. Note that
the N4880A must be connected to the J-BERT and configured in
order to be used.
You can configure the analyzer’s clock to External Clock or Internal CDR.
If Internal CDR is selected, parameters such as Loop Bandwid th, Peaking,
and Expected Transition Density can be modified.
50 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Using the Software 5
Figure 32 Timing Setup Dialog
Keysight N5990A-301 PCI Express Link Training Suite User Guide 51
5 Using the Software
Jitter/SSC
Figure 33 Signal Impairments section
Click Jitter/SSC (see Figure 33) to access the Jitter Setup window
(
Figure 34). This window allows different types of jitter to be defined
when the hardware jitter sources are available:
•Spread Spectrum Clocking
• Sinusoidal Clock Jitter
• Periodic Jitter
• Compliance Spectral RJ
Note that the composition of available jitter sources is different for
every spec version and DUT type (which is selected in the
Physical Parameters
dialog) on the main window.
PCIe
Note that when any slider is moved, the corresponding parameter
will be written to the hardware immediately.
Otherwise click
Apply. When you change any parameter, for
example, you enter a new value into a text- box; the corresponding
Apply button is highlighted. This means that you have to click Apply
in order to activate your changes.
If you use calibration data, the compliance jitter values will use
calibrated levels. However, jitter parameters that are not covered
by the specification will not be calibrated.
Note that some jitter/SSC parameters will reset the sequencer
when modified. With default settings, this means you must click
the
Manual Trigger button again to start link training. The PCIe Link
Training Suite tries to minimize the sequencer resets as much as
possible, but it is recommended that you frequently observe (or
watch) the sequencer state while changing the jitter or SSC
parameters.
52 Keysight N5990A-301 PCI Express Link Training Suite User Guide
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Interferences
Figure 34 Jitter Setup Dialog
Click Interferences (Figure 33) to access the Sinusoidal Interferences
Setup
(Figure 35). You can modify the Common Mode and Differential
Mode
sinusoidal interferences.
If you use the N4903B as a pattern generator, and if it is connected
to an 81150A AWG, common-mode interference is generated
using this AWG. If no AWG is connected, common-mode
interference is generated with the J-BERT J20 module. The J20
module is less accurate and cannot be combined with
Keysight N5990A-301 PCI Express Link Training Suite User Guide 53
5 Using the Software
differential-mode interference. In any case, ensure that either the
AWG or the J20 module is properly connected to the pattern
generator.
If you use calibration data, the compliance interference values will
use calibrated levels.
Voltage Levels
Figure 35 Sinusoidal Interference Setup Window
You can set the voltage levels for every output independently. Note
that when any slider is moved, the corresponding parameter will be
written to the hardware immediately.
Otherwise, click
Apply Levels (Figure 36). Note that the “Apply Levels”
button also applies the de-emphasis levels (if available).
You can also use the “Apply” button in the lower left corner of the
window to apply all parameters at once. Alternatively, you can click
the “Apply” command under the “Instruments” menu, or press
F6
on your keyboard.
54 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Figure 36 Voltage section
Using the Software 5
De-Emphasis
The “Outputs” button is only available for the M8020A generator.
Clicking
Outputs will enable or disable the M8020A outputs. If the
button is green, it means that the outputs of the M8020A are
switched ON and if red, implies that the outputs are switched OFF.
If an N4916B is connected to the J-BERT, you can control the
de-emphasis and pre-shoot levels as shown in
Figure 37 De-Emphasis Section
Figure 37.
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5 Using the Software
Bit Error Rate Measurement
The three control tabs are:
Equal - Sets the de-emphasis and pre-shoot in dB
Tap - Sets the FIR tap coefficients
Ampl - Sets the emphasized and de-emphasized voltage levels
Note that when any slider is moved, the corresponding parameter
will be written to the hardware immediately. Click the “
“Apply Levels” button.
Apply” or
Click Start BER Measurement (Figure 38), to automatically poll the
J-BERT's bit and error counters. By default, the displayed BER (Bit
Error Rate) is calculated from the total number of bits and total
number of errors. Click the
Accum button to the left side of the BER
display to toggle to the current BER, which is the calculated BER of
the last error counter reading. Note that these values may not
necessarily be always equal to the BER displayed in the J-BERT,
since the measurement intervals might be different.
Figure 38 Bit Error Rate Measurements
Click Reset BER Measurement to reset the bit and error counters.
The BER can be used to determine whether link training was
successful or not. A very high value of BER and increasing error
count could indicate that link training was not performed, because
the error counter is always programmed to only compare the
loop-back pattern.
56 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Sequencer
Using the Software 5
The group box in Figure 39 shows the Sequencer control.
Figure 39 Sequencer Control
The current state of the Sequencer is shown in Figure 39 when you
enable the “Poll Sequence State” option in the “Options” menu.
When the sequence contains a loop with a manual break condition,
click
Manual Trigger to end the loop.
BERT Control
Figure 40
shows the BERT control where you can control the
sequencer, the pattern generator, and the analyzer.
Figure 40 BERT control
Clicking “Insert Bit Error” causes the J-BERT to insert a single bit
error into the data stream. This can be useful to verify that the DUT
is in loop-back. When the DUT is not in loop-back, inserting bit
errors does not affect the bit error and BER counters.
Click
Analyzer Auto Align to force the analyzer to automatically align
with the incoming data. This is usually necessary after the pattern
generator is restarted, for example, when a new pattern has been
downloaded.
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5 Using the Software
Saving and Loading Settings
Expert Mode
Exporting The Script
Click Apply and Save in the main menu or on the main window to
store the current settings. Note that before the settings are saved,
they are applied to the hardware. The settings are saved only when
they are successfully applied to the hardware, which guarantees
that only such settings that are consistent are saved.
Click
Load and Apply to restore the settings at any time. The
restored settings are then immediately applied to the hardware.
In the “Options” menu, you can enable “Expert Mode”. This mode is
recommended for advanced users and offers some more parameters to
modify. The main advantage of the Expert Mode is the possibility of editing the
link training sequence and pattern using a special script.
Once you have found a link training sequence suitable for the DUT, you may
want to export that sequence, either to use it later or to the automated test
solution software.
To export the script that is currently being used for the training sequence,
click
File > Export Script. This saves the script to a file, regardless of whether
you defined it via parameters or by editing the PCIe generic script. The next
section provides details about the scripts.
58 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Script Editing
Using the Software 5
The main advantage of the Expert Mode is the ability to edit the
link training sequence and pattern using a script. This allows you to
define virtually any kind of pattern, whereas the methods
mentioned earlier in this document only allow those patterns to be
generated that are in sync with the PCIe link training methodology.
To edit the script, you must enable
Expert Mode and define the
script as the source of the pattern. By default, the pattern that is
downloaded to the J-BERT is defined via parameters, such as the
ones contained in the “Link Training Pattern” box. However, in
Expert Mode, the group box Pattern/Sequence Script is
automatically available (see
Figure 41)
Keysight N5990A-301 PCI Express Link Training Suite User Guide 59
Figure 41 Expert Mode
5 Using the Software
When you select “Generate From Parameters”, the pattern will be
automatically generated, that is, in the same way as in non-Expert
Mode. When you select “Use Custom Script” (see
Figure 42), a
custom script is used. The parameters for the automatically
generated script are disabled, and have no influence.
Figure 42 Expert Mode with Custom Script
Click Edit Script to begin editing the script (Figure 42). The script
editor, as shown in
can edit the sequence and pattern, with a unified syntax. It allows
you to define the data using terms common to PCIe. For example,
to generate a TS1 ordered set with the loop-back flag set, you can
use the macro “TS1(loop-back)”. You can also use the menu to
convert pattern data between different representations (binary,
hexadecimal, 8b/10b).
Clicking
Process PCIe Macros starts a script translation, where all
PCIe specific macros and symbol names are converted into their
binary, 8b/10b, or 128b/130b representation.
When the auto-generated script is used, the “Edit Script” button
changes to “View Script”. In that case, the script can only be
changed by modifying the parameters in the main window.
Figure 43, is displayed. In the script editor, you
60 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Using the Software 5
Limitations
Figure 43 PCIe Script Editor
When editing the script, the resulting pattern must meet the
J-BERT''s granularity requirements (512-bits for N4903B J-BERT
and 80-bits for M8020A J-BERT).
If the pattern you want to define does not fit this granularity, you may repeat
the pattern until the granularity requirement is met (using the {} operator), or
place a Pad0() macro somewhere to fill the pattern with zeros.
For more details, refer to the PCI Express Link Training Suite Language Guide.
Keysight N5990A-301 PCI Express Link Training Suite User Guide 61
Keysight N5990A-301 PCI Express Link Training Suite
User Guide
6 Troubleshooting
Startup Fails / 64
Slow Response / 65
Link Training Fails / 66
6 Troubleshooting
Startup Fails
The anti-virus software Sophos Endpoint Security is known to classify the
PCIe Link Training Suite as a virus and prevent it from executing. Starting
the Link Training Suite then leads to an error message which is “Windows
cannot access the specified device, path, or file”. In this case, please check
whether the anti-virus software has blocked the executable file of the PCIe
Link Training Suite and add it to the exceptions, if necessary. Note that you
will probably have to repeat this procedure for some of the DLLs.
For Example: PcIeFrameGenerator.dll
64 Keysight N5990A-301 PCI Express Link Training Suite User Guide
Slow Response
Troubleshooting 6
If there is a slow response from the PCIe Link Training Suite user interface,
this might be a result of a poor remote connection. Probably, the delay
over Ethernet is too high.
In most cases, disabling the BER polling and the sequencer status polling
is helpful.To disable the BER polling, click Stop in the Bit Error Rate
Measurement group.To disable the sequencer state polling, uncheck Poll
Sequence Status in the Options menu.
Keysight N5990A-301 PCI Express Link Training Suite User Guide 65
6 Troubleshooting
Link Training Fails
If link training fails, you might want to check the following points:
• Did you click “Apply” after connecting and adjusting all your
parameters? Note that simply connecting the instruments doesn’t
automatically download the pattern and settings.
• Is the injected jitter too high? Try reducing or disabling the injected
jitter in the “Jitter/SSC” dialog.
• Are the timing and voltage levels, and the de-emphasis correct.
• Is the selected link training sequence suitable for your DUT? Probably
using a tweaked sequence will help your DUT to get into Loop-back.
Try the “Preset...” button in the “Sequence to Loop-back Mode” dialog.
This dialog opens when you click “Edit Parameters” in the “PCIe
Training Parameters” group of the main window.
66 Keysight N5990A-301 PCI Express Link Training Suite User Guide
This information is subject to
change without notice.
© Keysight Technologies 2017
Edition 3.0, July 2017
www.keysight.com
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