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USB 2.0 Bus Analyzer
Introduction
The USB2SnooperTM is one more innovative product from NitAl, which helps USB developers to debug USB2.0 specifications based device under development. USB2SnooperTM is user friendly Bus Analyzer for real time capturing and analysis of USB traffic. USB2SnooperTM captures bus traffic non-intrusively & can be connected between any two USB nodes communicating with each other at HS to HS , HS/FS , FS/LS or LS speeds.
USB2SnooperTM captures packets on the USB interface & stores them in the PC memory. The product comprises of a PCI add-on card and a user-friendly Software application supporting Microsoft Windows 2000 and Windows XP operating Systems. Capture buffer can be optimally used with the help of real time triggering & pre filtering. Once data is captured the user can quickly pinpoint the data of interest with the use of post filtering & search functions.
This innovative solution to convert PC into powerful Bus analyzer provides advantages over stand alone Analyzers for quick real time capture & analysis. It also Analyzer supports upcoming USB-OTG protocol thus enabling user to help reduce time to market.
Feature Overview
Compatible to USB2.0 & USB1.1 specs
Supports HS, FS and LS speeds
Provides USB-ON-THE-GO ( OTG ) support
Non-intrusive snooping. Does not disturb device under test. Can be connected in any branch of USB Bus
Self powered. Does not consume power from USB cable
Provides Packet View, Transaction View, Control transfer view, Summary view, Raw bit view for effective packet analysis
Comes as a PCI add-on card for fast transfer to PC memory. Optimizes the usage of PC's available memory. Works faster !
External Trigger input & external trigger outputs are for enhanced capture & trigger Oscilloscopes to observe electrical condition on the Bus
Time stamping for each captured packet with 16.67ns resolution
Provides very high capture buffer depending on the PC memory. On Windows 2000 one can easily go up to 540MB of capture buffer depending on Memory support
Supports Microsoft Windows' 2000 & XP Operating Systems
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Triggering Options
USB2SnooperTM provides extensive triggering methods to help analyze the USB traffic & capture information to pin point specific problem area. In all USB2SnooperTM supporting 16 triggers, can be divided into 5 groups to build a powerful sequencing mechanism. Logical relationships can be defined within groups & user can define occurrence of trigger conditions from 1 to 256 in numbers. Triggers can be set on Bus states of USB traffic & even external trigger can form part of groups. Following are the various triggers provided,
Extensive triggers to capture the data intelligently
Ability to provide trigger on Transactions, Packets
Trigger occurrence count up to 256
Triggering on Data pattern to match the data pattern
Trigger on Device Request
Trigger on Bus states RESET, SUSPEND, RESUME
Trigger on Errors like PID, CRC (CRC5 & CRC16), PHY Errors
Ability to adjust trigger position in capture buffer
Logical relationships AND, OR, AND ANY, ANY NEXT
The following figure shows various combinations available for triggering.
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Pre-filtering is similar to triggering, in the sense that it is evaluated in real time during data capture, unlike post-filtering which is applied after data is captured. In pre-filtering, some data pattern or combination of data patterns can be set as the filter event. User can either accept / reject the packets or transactions meeting the condition. This feature enhances the capability of USB2SnooperTM to capture a large traffic of real interest. For Example SOF packet is generated on every Frame & Micro frame (for HS) that occupies a lot of space. This can be filtered out. NAK , NYET & PING are other packets in USB traffic, which can be filtered out without compromising any valuable data to optimize the capture buffer utilization. Gist of the pre-filtering features is as below,
- Pre-filtering
can be set on transactions.
- SOF
packets
- Transactions
like IN, OUT, SETUP, SSPLIT, CSPLIT, PING
- Transactions
to the specific address/endpoint
- Selection
between Acceptance or rejection of the transaction.
- Supports
3 filters, which are applied in real time on the same incoming USB packet.
- Ability
to filter out or IN specific Data pattern that can be user defined up to
4 bytes.
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Post filters are supported to help user wade out unwanted information from the capture buffer & locate traffic of the interest. Typically post filter helps in analyzing captured buffer for various conditions & snap shots of post filtered data can be stored on hard disk for future reference. Post filters are applicable at transaction level to keep the captured data meaningful as per USB protocol. Post filters can be applied to any PID, to specific end point, Bus states, etc.
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Display Options
The Display option to analyze the captured buffer forms the main function of USB2SnooperTM. It provides various views so the user can observe the data of interest as per the needs. Since it captures over millions of packets, a quick display of captured data is most important. USB2SnooperTM can display all the packets (over millions!) in few seconds after the capture is over. In order to perform detailed analysis, which involves computing, USB2SnooperTM provides various views, which work on chunk of data at a time. User can quickly move through entire capture buffer using this technique. Following is the summary of various display option supported in USB2Snooper TM.
- Packet
views Displays Bus states,
Packets and Data with timing information.
- Transaction
view Displays Transactions
level summary
- Control
Transfer View Displays Control transfer view to see how the devices are
configured.
- Summary
View Provides summary of
entire buffer. Such as no of Errors, Tokens etc.
- Raw
Bit View Displays packet on bit level in graphical format
- Extensive
display options to select packets or transactions of interest.
- Identification
of the Trigger packet
- Extensive
search capabilities for any particular packet.
- High
resolution time stamping.
- Automatic
detection and high lighting of error conditions.
- Textual
report generation, print and data export options.
Following Picture shows typical transaction view displayed by the USB2SnooperTM.
Raw Bit Packet View:
Transaction View: OTG SRP Decode
Transaction View: OTG HNP Decode
Transaction View: Trigger on Error Packet
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Operating Modes
The
USB2SnooperTM configurations are shown. The same are applicable to USB1.1
devices.
  Real time capture Mode
In this mode, USB2SnooperTM will perform real time capture of USB traffic
and dump it to the PC memory. During real time capture most of the software
features are not available. Real time capture can be exited in two ways
Off-line analysis Mode
In this mode, previously captured data is available for the analysis. User
can also alter the triggering, filtering and environmental settings in this
mode.
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