Teledyne Line Code User Manual
Instruction Manual
Line Code and Symbol Decoders:
Manchester
NRZ
8b/10b
64b/66b
Line Code and Symbol Decoders Instruction Manual
© 2013 Teledyne LeCroy, Inc. All rights reserved.
Unauthorized duplication of Teledyne LeCroy documentation materials other than for internal sales and
distribution purposes is strictly prohibited. However, clients are encouraged to distribute and duplicate
Teledyne LeCroy documentation for their own internal educational purposes.
Teledyne LeCroy is a registered trademark of Teledyne LeCroy, Inc. Windows is a registered trademark
of Microsoft Corporation. Other product or brand names are trademarks or requested trademarks of
their respective holders. Information in this publication supersedes all earlier versions. Specifications are
subject to change without notice.
922663 Rev A
March 2013
Instruction Manual
922663 Rev A
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TABLE OF CONTENTS
Introduction ...................................................................................................... 2
About This Manual ............................................................................................... 2
Serial Decode ....................................................................................................... 2
General Approach ................................................................................................ 3
Setting Up the Decoder ...................................................................................... 4
Manchester and NRZ ........................................................................................... 4
8b/10b and 64b/66b ............................................................................................ 7
Verify Bit-Level Decode ...................................................................................... 10
Enable/Disable Decoder .................................................................................... 10
Working with the Decoded Waveform .............................................................. 11
Serial Decode Annotation .................................................................................. 11
Search Waveform .............................................................................................. 12
Working with the Results Table ........................................................................ 14
Customize Decode Result Table ......................................................................... 14
Export Decode Result Table ............................................................................... 15
Teledyne LeCroy Service Centers ...................................................................... 16
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Introduction
About This Manual
Teledyne LeCroy offers different toolsets for decoding and debugging serial data streams. These toolsets
may be purchased as optional software packages, or are provided standard with SDA and DDA model
oscilloscopes.
This Line Code and Symbol Decoders Instruction Manual explains how to use the following toolsets:
NRZ Configurable Decoder
Manchester Configurable Decoder
8b/10b Decoder
64b/66b Decoder
Assumptions
This manual is presented with the assumption that:
You have a basic understanding of the various serial data standard physical and protocol layer
specifications, and know how these standards are used in embedded controllers.
You have a basic understanding of how to use an oscilloscope, and specifically the Teledyne
LeCroy oscilloscope on which the serial trigger and decode option is installed. Only features
directly related to serial data decode are explained in this manual; please see the oscilloscope
online Help file, Operator's Manual, or Getting Started Manual for other instructions.
You have purchased and installed one of optional serial data decoders described in this manual.
Compatibility
Teledyne LeCroy is constantly expanding coverage of serial data standards and updating software. Some
capabilities covered in this documentation may only be available with the latest version of our firmware.
You can download the firmware update from teledynelecroy.com.
While some of the screen images in this manual may not exactly match what is seen on your
oscilloscope display—or show an example taken from your protocol—be assured that the functionality is
nearly identical, as much functionality is shared.
Serial Decode Technical Overview
The algorithms described here at a high level are used by all Teledyne LeCroy serial decoders sold for
oscilloscopes. They differ slightly for serial data signals that have a clock embedded in data or a clock
separate from data. See the Overview for each encoding scheme later in this manual for more specific
information.
The first software algorithm examines the embedded clock for each message based on a default (or user
specified) vertical level. Once the clock signal is extracted or known, the algorithm examines the
corresponding data signal at a predetermined vertical level to determine whether a data bit is high or
low. The default vertical level is usually set to 50% and is determined from a measurement of peak
amplitude of the signals acquired by the oscilloscope. It can also be set to an (absolute) voltage level, if
desired. The algorithm intelligently applies a hysteresis to the rising and falling edge of the serial data
signal to minimize the chance of perturbations or ringing on the edge affecting the data bit decoding.
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NOTE: Although the decoding algorithm is based on a clock extraction software algorithm using a
vertical level, the results returned are the same as those from a traditional protocol analyzer using
sampling point-based decode. In addition, the clock extraction technique allows partial decoding of
messages in the event of physical layer noise, in many cases, whereas a protocol analyzer usually
cannot. This is a significant advantage for the Teledyne LeCroy software algorithm.
After determining individual data bit values, another algorithm performs a decoding of the serial data
message after separation of the underlying data bits into logical groups (Header/ID, Data Length Codes,
Data, CRC, Start Bits, Stop Bits, etc.) specific to the protocol.
Finally, another algorithm applies a color overlay to the decoded trace with annotations to mark the
transitions in the signal and displays decoded message data in tabular form. Various compaction
schemes are utilized to show the data during a long acquisition (many hundreds or thousands of serial
data messages) or a short acquisition (one serial data message acquisition). In the case of the longest
acquisition, only the most important information is highlighted. In the case of the shortest acquisition,
all information is displayed (Header/ID, Data Length Codes, Data, CRC, Start Bits, Stop Bits, etc.) with
additional highlighting of the complete message frame.
General Approach
The order of your interaction with the decoder software in many ways mirrors the order of the
algorithms. You will:
Assign a protocol/encoding scheme, an input source, and a clock source (if necessary) to one of
the four decoder panels using the Serial Data and Decode Setup dialogs.
Complete the remaining dialogs required by your protocol/encoding scheme to decode
Transitions, Bits and Words.
Work with the decoded waveform and result table to analyze the decode.
While not required, we recommend the following general approach to decoding:
1. Set up the decoder.
2. Acquire a single burst of relevant data, then run the decoder.
NOTE: If the sampling rate (SR) is insufficient to resolve the signal adequately based on the bit rate
(BR) setup or clock frequency, the protocol decoding is turned OFF to protect you from incorrect
data. The minimum SR:BR ratio required is 4:1. It is suggested that you use a slightly higher SR:BR
ratio if possible, and use significantly higher SR:BR ratios if you want to also view perturbations or
other anomalies on your serial data analog signal.
3. Use the various analysis tools to verify that transitions are being correctly decoded. Tune the
decoder settings as needed.
4. Once you know you are correctly decoding transitions, continue making small acquisitions and
running the decoder for bits then words in turn, tuning the decoder as needed for each.
The decoder settings you verify on a few bursts will be reused when handling many packets.
5. Run the decoder on acquisitions of the desired length.
You can disable/enable the decoder as desired without having to repeat the set up and tuning
provided the basic signal characteristics do not change.
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Setting Up the Decoder
You can preset up-to-four, independent decoders using the same or different protocols and data
sources. These decoders can be enabled simultaneously or separately, and you can select for each what
data appears on the display.
1. Touch the Front Panel Serial Decode button (if available on your oscilloscope), or choose Analysis >
Serial Decode from the oscilloscope menu bar to access the Serial Decode dialogs.
2. On the same row as the Decoder #:
Select the desired Protocol to use. The selections will depend on the software options
installed on your instrument.
Select the Source (Data) to be decoded. This can be any signal input channel, memory, or
math function. Depending on your Protocol selection, you may be required to select more
than one source. The requisite number of fields will automatically appear.
3. Touch the Setup button to open the Decode Setup dialog. If you use this method rather than the
tab, the correct decoder will be selected by default.
TIP: You can quickly start setup for the other decoders by using the Decode # buttons at the left of
the Decode Setup dialog. You don't have to step back to the Serial Decode dialog to start the setup.
Controls with the same label on either dialog share the same function.
4. Go on to complete the settings required for the specific protocol.
Manchester and NRZ
Overview
The Manchester and NRZ Configurable Decoders developed by Teledyne LeCroy are tools aimed at
decoding serial data that is not supported by mainstream decoders. Its goal is to decode fairly simple
serial data not belonging to the historical protocols such as I2C, UART and SPI, or the dedicated
protocols such as CAN, LIN, MIL-1553, ARINC 429, MIPI, Ethernet, etc.
Because they are aimed at general encoding schemes, rather than specific protocols, configuring the
decoder to make it possible for the general algorithms to execute on a particular signal requires a little
more knowledge of serial data encoding logic than with previous decoders. Once the settings have been
determined for a given signal, they can be stored in internal panel files and recalled later, when analysis
on the same signal is required.
Although separate products, in its current form the configurable decoder operates the same for
Manchester or NRZ streams, and they will be treated as one in this manual.
There are some limitations to be observed:
The product will handle digitally encoded data on a single signal, with 2 levels (High and Low), a
constant Bitrate between 10 bit/sec to 10 Gb/sec at any voltage levels, and a timeout(or Inter
Frame Gap) allowing the stream to be decoded into separate bursts of data on the line.
The product will not handle multi-line signals, signals with more than 2 voltage levels, stuff bits
and/or complex synchronization pulses.
While flexible, the product is not suitable for complex protocol streams (e.g., i.e. CAN, MIL-STD-
1553, FlexRay, MIPI) or 2- or 3-signal transmissions (e.g., I2C or SPI). Dedicated decoders are
available for these protocols.
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