LeCroy High Speed Serial Triggers User manual

Brand: LeCroy

Model: High Speed Serial Triggers

Type: User manual

High Speed

Serial Trigger & Decode

for Protocols:

8b/10b

64b/66b

NRZ 80-bit Pattern

High Speed Serial Triggers and Decoders Instruction Manual

This document does not contain export-controlled information.

Unauthorized duplication or resale of Teledyne LeCroy publications is strictly prohibited. Customers are permitted to

duplicate and distribute Teledyne LeCroy, Inc. documentation for internal educational purposes only.

Teledyne LeCroy is a trademark of Teledyne LeCroy, Inc., Inc. 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.

23 January 2024

high-speed-serial-triggers-im.pdf

Contents

Introduction 1

8b/10b Option 1

64b/66b Option 2

80B Symbol Options 2

Serial Trigger 3

Requirements 3

Restrictions 3

Serial Trigger Inputs 3

8b/10b Trigger Setup 4

64b/66b Trigger Setup 8

NRZ 80-bit Pattern Trigger Setup 12

Linking Trigger and Decoder 14

Using the Decoder with the Trigger 15

Saving Trigger Data 15

Serial Decode 16

Decoding Workflow 17

Serial Decode Dialog 17

Decoder Set Up 18

Setting Level and Hysteresis 22

Failure to Decode 23

Reading Waveform Annotations 24

Serial Decode Result Table 25

Searching Decoded Waveforms 31

Improving Decoder Performance 32

Appendix A: Automating the Decoder 33

Configuring the Decoder 33

Accessing the Result Table 33

Reading the Structure of the Result Table 33

Modifying the Result Table 35

Technical Support 36

High Speed Serial Triggers and Decoders Instruction Manual

About This Manual

This manual explains the basic procedures for using serial data trigger and decode software options for Teledyne

LeCroy oscilloscopes. It is assumed that you have a basic understanding of the serial data physical layer

specifications, and how to use the oscilloscope on which the option is installed. Only features specific to this product

are explained in this manual.

While some images may not exactly match what is on your oscilloscope display—or may show an example taken

from another standard—be assured that the functionality is identical. Product-specific exceptions will be noted in the

text.

Some capabilities described may only be available with the latest version of our MAUI®software. Updates are

available from the software download page at teledynelecroy.com under Oscilloscope Downloads > Firmware

Upgrades.

Introduction

8b/10b Option

Note: If you have installed other -DME or -TDME options, the dialogs for Measure/Graph and Eye Diagram

creation will appear when the decoder is open. They may or may not appear "grayed out." We do not

guarantee the correct operation of the functionality unless for this protocol.

Teledyne LeCroy offers an 8b/10b Symbolic Decoder for signals based on the 8b/10b encoding scheme. 8b/10b is

not a protocol, per se, but a widely used method to encode 8-bit data words within a 10-bit symbol, or character. The

extra bits are used to ensure the long-term ratio of 1s and 0s transmitted is 1:1, and the serial data encoding is DC

free.

lAny bit transmission longer than five consecutive 1s or 0s is prohibited, which limits the requirements for the

lowest required bandwidth in the serial data transmission channel.

lThe difference in number between 1 bit and 0 bit transmissions is never more than two.

While there are theoretically 1024 (2 to the 10th power) different 8b/10b encoded bytes possible, far fewer are

allowed based on these aforementioned rules.

In order to maintain the DC-free nature of the signal, a running disparity counter is kept for each byte. This count

reflects the bias of 1s or 0s from the transmitted byte, and the 8b/10b encoder makes use of the value of this

running disparity counter to determine whether to encode the next byte as a symbol of +1 or -1 disparity so as to

keep the overall DC bias of the transmitted signal at zero. Thus, there are two valid bit sequences for any byte,

depending on the running disparity used.

Serial data standards that use 8b/10b encoding also define special symbols or control characters that indicate start

or end-of-frame, skips, link idles, or other protocol-specific non-data information. These are commonly referred to as

primitives. Many high-speed serial data standards, such as PCI Express, SATA, SAS, Fibre Channel, etc. use 8b/10b

as the underlying encoding method below the protocol layer. Each standard defines its own set of primitives.

Primitives convey more basic information than contained in a full protocol decode, but they can be valuable as well

for debugging or quality control purposes.

High Speed Serial Triggers and Decoders Instruction Manual

64b/66b Option

Note: If you have installed other -DME or -TDME options, the dialogs for Measure/Graph and Eye Diagram

creation will appear when the decoder is open. They may or may not appear "grayed out." We do not

guarantee the correct operation of the functionality for this protocol.

Teledyne LeCroy offers a 64b/66b Symbolic Decoder for signals based on the 64b/66b encoding scheme. Similar to

8b/10b, 64b/66b is not a protocol, per se, but a widely used method to encode 64-bit data within a 66-bit line code.

The overhead of 64b/66b is considerably less than 8b/10b encoding due to the higher ratio of data bits to coding

length.

64b/66b is commonly used in optical signaling protocols, such as 10GFC (10 Gb/s FiberChannel), 10G Ethernet

Passive Optical Network (10G-EPON), and InfiniBand, and also for varieties of 10GBASE, 40GBASE, and 100GBASE

Ethernet.

The 66-bit data frame consists of a two-bit synchronization header), which is never scrambled, followed by 64 bits of

data/control byte transmission, which is always scrambled.

lA sync header of 01 (time-ordered) indicates the 64 bits are entirely comprised of data.

lA sync header of 10 (time-ordered) indicates the 64 bits are comprised of an 8-bit type field followed by 56 bits

of control information and/or data.

lPreambles of 00 and 11 are disallowed and generate errors if present.

The 8-bit type field is defined by the protocol that employs the 64b/66b encoding. The remaining 56 or 64 data bits

are then scrambled using a self-synchronous scrambler function to ensure a reasonable distribution of zeros and

ones in the data. However, there is no requirement for the distribution of zeros and ones.

Serial data standards using 64b/66b encoding may also define special signal codes indicating protocol-specific

commands or functionality.

64b/66b encoding differs from 8b/10b encoding in that 64b/66b coding is designed for clock recovery and stream

realignment, but not DC balance or run length limitation, whereas 8b/10b encoding ensures DC balance and run

length limitation. Therefore, it is possible for there to be 65 continuous zeros or ones and not violate the encoding

scheme, provided the scrambling pattern and data are aligned. More than 65 continuous ones or zeros are not

permitted because it violates the clock recovery requirements.

80B Symbol Options

80B Symbol TD options are available to activate 80-bit NRZ pattern triggering on oscilloscopes equipped with high-

speed serial trigger hardware. These options include the 8b/10b and 64b/66b decoders and enable symbol

triggering for protocols based on these encoding schemes, such as PCIe, SAS, SATA, USB, FiberChannel, Ethernet,

DisplayPort and more.

Note: Similar options designed for oscilloscopes with the legacy 3.125 GB/s serial trigger hardware activate

80-bit NRZ pattern triggering and 8b/10b (only) symbol triggering.

Serial Trigger

"T" options provide advanced serial data triggering in addition to decoding. Serial data triggering is implemented

directly within the hardware of the oscilloscope acquisition system. The serial data trigger scrutinizes the data

stream in real time to recognize "on-the-fly" the user-defined serial data conditions. When the desired pattern is

recognized, the oscilloscope takes an acquisition of all input signals as configured in the instrument's acquisition

settings. This allows decode and analysis of the signal being triggered on, as well as concomitant data streams and

analog signals.

Note: The trigger and decode systems are independent, although they are seamlessly coordinated in the

user interface and the architecture. It is therefore possible to use the serial trigger without decoding the

acquisition, or to decode acquisitions made without using the serial trigger.

Requirements

Serial trigger options require the appropriate hardware (please consult support), an installed option key, and the

latest firmware release. See Serial Trigger Inputs for supported input channels and devices.

Restrictions

Triggering on Sequence Mode acquisitions is not supported.

Serial Trigger Inputs

8 Gbit 14.1 Gbit 16 Gbit

SDA/WaveMaster 8 Zi-B Std: C4

SDA/WaveMaster 8000HD Std:ProLink/ProAxial C3

DBI: 1.85 mm C3

Std: ProLink/ProAxial C3

DBI 1.85 mm C3

SDA/LabMaster 10 Zi Std: C4

DBI: C3B

Note: If using a LabMaster system with multiple acquisition modules, the module with the serial trigger

hardware installed in it must be connected as Channels 1 through 4.

High Speed Serial Triggers and Decoders Instruction Manual

8b/10b Trigger Setup

To access the serial trigger dialog:

lTouch theTrigger descriptor boxor chooseTrigger > Trigger Setup from the Menu Bar.

lTouch the Serial Type button, and the 8b/10b Standard button.

Then, working from left to right, make the desired selections from the 8B10B dialog.

Source Setup

Caution: If using a differential probe, make sure the + side of the probe is connected to the + side of the

serial data signal. If using a cabled input, make sure the + side of the serial data signal is connected to the

trigger input. If this is not done, the input signal will be the inverse of what is expected, and the trigger will

not trigger properly. To correct this problem, either reverse the probe connections, or check the Invert box

next to the Source Channel indicator.

The bit rate can be computed from the acquisition data in many circumstances, but if the pattern is not random, the

bit rate may be miscalculated as a sub-multiple of the actual bit rate. For best results, enter a Bit Rate close to what

you expect for the serial data signal, then touch Compute Bit Rate.

If a serial data signal is detected but the bit rate does not match, an “unlocked” indicator will appear under the PLL

(phase-locked loop) label.

Once the bit rate is properly detected and the PLL locks onto the serial data signal, the “unlocked” indicator will

change to “locked.”

Serial Trigger

Equalizer

This selection is available only with the 6.5 Gb/s and 14.1 Gb/s triggers.

Very high frequencies, such as those found in serial data signals with speeds >5 Gb/s, may be highly attenuated as

they travel through a serial data channel, backplane or printed circuit board. While there are tools available from

Teledyne LeCroy to software equalize the acquisition data (e.g., Eye Doctor II, VirtualProbe), this does not help for

triggering, since the hardware trigger FPGA triggers on the oscilloscope acquisition datastream prior to any post-

acquisition software equalization. Therefore, Teledyne LeCroy provides the capability to equalize in the trigger FPGA

through the use of a Low (2 dB), Medium (5 dB), or High (9 dB) equalization “boost.” Touch the HF Boost field, and

make your selection from the pop-up menu.

Note: Equalization is applied only at the FPGA inputs and is not displayed on Channel 4.

Pattern Type

The trigger can be set to:

lSymbol OR—any one of a group of symbols

lSymbol String—a single 8b/10b symbol or a string of symbols

lPrimitive—a pre-defined protocol or a user-defined primitive sequence of symbols

lProtocol Error

Make your selection under Pattern Type, then complete the settings that appear to the right of this selection.

To highlight the triggered area and make it easier to verify a valid trigger, check Highlight Pattern.

Symbol OR Trigger

Up-to-six 8b/10b symbols may be added to an OR configuration (as shown above). Detection of any one of these

symbols will result in a successful trigger. Touch Symbol OR, then for each Symbol N, select a:

lType of KSymbol or DSymbol

lAn allowed Value

lAn RD (running disparity) of Positive, Negative, or Either

High Speed Serial Triggers and Decoders Instruction Manual

Symbol String Trigger

Up to eight 8b/10b symbols may be configured in a sequential string. Detection of the complete symbol string will

result in a successful trigger.

Touch Symbol String and for each Symbol N, select a:

lType of KSymbol, DSymbol, or None

lAn allowed Value

lAn RD (running disparity) of Positive, Negative, or Either.

If fewer than eight symbols are required, choose Type None for the first unnecessary Symbol. If None is chosen, no

further selections are permitted to the right of that symbol.

Primitive Trigger

Instead of defining a symbol string for a particular protocol-defined primitive, you may directly choose the protocol

and primitive. Touch Pattern Type Primitive, then touch Protocol and choose the desired protocol from the pop-up

menu.

For some protocols, you can select a Primitive Type as well. For example, if you choose USB3 protocol, you will see a

pop-up menu of primitives as defined in the USB3 standard:

If you choose Protocol Others, then Primitive File is enabled, and you can select a user-defined primitive file from a

specific drive location. The file format is simple, and you can easily create a new file by editing the existing primitive

file created for each pre-defined protocol.

Serial Trigger

Error Trigger

Error triggering may be performed by choosing Pattern Type Protocol Error and selecting an error condition:

lInvalid Symbol Error – Each 8b/10b symbol contains 10 bits; theoretically, there are 1024 possible 10-bit

patterns. However, only 256 of them are valid. If this selection is checked, then the error trigger will trigger on

any of the disallowed 768 10-bit patterns.

lRunning Disparity Error – 8b/10b encoding is DC free. To ensure this, the long-term ratio of 1s and 0s must be

50% each. Each symbol may have a maximum +/-2 difference in the number of 1s and 0s, and each symbol

must end with either a +1 (positive) or -1 (negative). If a symbol does not meet these requirements, it is a

Running Disparity Error, and this selection will cause a trigger.

You can choose to trigger on either or both errors by checking the desired boxes.

High Speed Serial Triggers and Decoders Instruction Manual

64b/66b Trigger Setup

To access the serial trigger dialogs:

lTouch the Trigger descriptor box or choose Trigger > Trigger Setup from the Menu Bar.

lTouch the Serial Type button, and the 64b/66b Standard button.

Then, working from left to right, make the desired selections from the 64B66B dialog.

Source Setup

Caution: If using a differential probe, make sure the + side of the probe is connected to the + side of the

serial data signal. If using a cabled input, make sure the + side of the serial data signal is connected to the

trigger input. If this is not done, the input signal will be the inverse of what is expected, and the trigger will

not operateproperly.To correct this problem, either reverse the connections, or check the Invert box next to

the Source Channel indicator.

The bit rate can be computed from the acquisition data in many circumstances, but if the pattern is not random, the

bit rate may be miscalculated as a sub-multiple of the actual bit rate. For best results, enter a Bit Rate close to what

you expect for the serial data signal, then touch Compute Bit Rate.

If a serial data signal is detected but the bit rate does not match, an “unlocked” indicator will appear under the PLL

(phase-locked loop) label.

Once the bit rate is properly detected and the PLL locks onto the serial data signal, the “unlocked” indicator will

change to “locked.”

Equalizer

This selection is available only with the 6.5 Gb/s and 14.1 Gb/s triggers.

Very high frequencies, such as those found in serial data signals with speeds >5 Gb/s, may be highly attenuated as

they travel through a serial data channel, backplane, or printed circuit board. While there are tools available from

Teledyne LeCroy (Eye Doctor II, VirtualProbe) to software equalize the acquisition data, this does not help for

triggering, since the hardware trigger FPGA triggers on the oscilloscope acquisition datastream prior to any post-

Serial Trigger

acquisition software equalization. Therefore, Teledyne LeCroy provides a capability to equalize in the trigger FPGA

through the use of a Low (2 dB), Medium (5 dB), or High (9 dB) equalization “boost.” Touch the HF Boost field, and

make your selection from the pop-up menu.

Note: This equalization is applied only at the inputs of the trigger FPGA and is not displayed on Channel 4.

Encoding

Choose to view/enter data in either Binary or Hex(adecimal) format.

Trigger Type

The trigger can be set on:

lBlock 1 OR 2 match—either Data Value 1 or Data Value 2 occurs

lBlock 1 THEN 2—Data Value 1 occurs followed immediately by Data Value 2

lInvalid SYNC—SYNC bits are not 01 or 10

lInvalid TYPE—the Block Type byte is not one of the valid choices

lBlock 1 match—Data Value 1 occurs (Data Value 2 is disabled on the UI)

lBlock 1 mismatch—any frame that is not Data Value 1 occurs

lBlock 2 match—Data Value 2 occurs (Data Value 1 is disabled on the UI)

lBlock 2 mismatch—any frame that is not Data Value 2 occurs

Your selection will change the remaining controls that appear on the dialog.

To highlight the triggered area and make it easier to verify a valid trigger, check Highlight Pattern.

High Speed Serial Triggers and Decoders Instruction Manual

Block Type and Data Bytes

Select a Block Type of Control, Data or Error. The trigger will only test blocks of this type.

Specify the Data Bytes that are to be tested by the trigger. The number of data bytes that should be entered will

depend on the block type. Enter the bytes from most significant to least significant. For example, if the three bytes

are “AABBCC”, then byte D7=AA, D6=BB and D=CC. After updating this field, Data Value 1 is populated.

Block Type Field and Control Characters

These controls appear only when using the “Control” Block Type.

Block Type Field uses the descriptions shown in Figure 49-7 of IEEE Std 802.3-2008. Choices are:

C0 C1 C2 C3/C4 C5 C6 C7 (0x1e)

C0 C1 C2 C3/O4 D5 D6 D7 (0x2d)

C0 C1 C2 C3/S4 D5 D6 D7 (0x33)

O0 D1 D2 D3/S4 D5 D6 D7 (0x66)

O0 D1 D2 D3/O4 D5 D6 D7 (0x55)

S0 D1 D2 D3/D4 D5 D6 D7 (0x78)

O0 D1 D2 D3/C4 C5 C6 C7 (0x4b)

T0 C1 C2 C3/C4 C5 C6 C7 (0x87)

D0 T1 C2 C3/C4 C5 C6 C7 (0x99)

D0 D1 T2 C3/C4 C5 C6 C7 (0xaa)

D0 D1 D2 T3/C4 C5 C6 C7 (0xb4)

D0 D1 D2 D3/T4 C5 C6 C7 (0xcc)

D0 D1 D2 D3/D4 T5 C6 C7 (0xd2)

D0 D1 D2 D3/D4 D5 T6 C7 (0xe1)

D0 D1 D2 D3/D4 D5 D6 T7 (0xff)

In Control Characters, enter the control bytes used in hex pairs. Control characters are 7 bits long, such that the msb

of each hex pair is not used. After updating this field, Data Value 1 is populated.

Note: The Data Bytes and Control Character options that appear on pop-up menus are displayed from left to

right for ease of reading, but this is opposite to how the values are entered in the Data Bytes and Control

Characters fields once you make a selection.

Data Value

Data Value 1 shows the 64 bits constructed from Data Bytes and Control Characters, ordered from most significant

to least significant. This ordering matches the ordering of the values entered in the Data Bytes and Control

Characters fields. To adjust the value, touch the field twice, then use the controls on the Virtual Keypad pop-up.

Serial Trigger

lPrevious and Next (arrows) position the cursor over characters that are to change.

l0,1, and Xinsert that character.

lBack clears one character back, like a Backspace key.

lClear will clear all highlighted characters.

lSet to Default restores the original string generated after making your Block Type and Data Byte selections.

lOK enters the keypad value into the Data Value 1 field.

Data Value 2 is populated when you press Copy Data Value 1 to 2. It is required only when the trigger conditions test

more than one block of data. To modify it, use the Virtual Keypad pop-up, the same as for Data Value 1.

Sync sets the value of the two sync bits. These are set automatically to “01” when BlockType is ”Control”, and to “10”

when BlockType is “Data”.

Bit Ordering

64b/66b data frames consist of a two sync bit preamble, which is never scambled, followed by a 64-bit payload,

which is always scrambled.

The decoded values shown on the touchscreen (in tables and dialogs) are user data, not the scrambled data

transmitted by the protocol. The trigger chip descrambles the input, compares it to the desired data, and triggers

when the descrambled data matches the desired data. However, the waveform trace you see on the screen is

scrambled data and does not exactly match the decoded user data.

Teledyne LeCroy has opted to order the 66 bits of the block from left to right (most to least significant, 66..0) in order

to allow users to easily match the data value for the block to the values entered for the data bytes and control

characters. Other documentation describing the 64b66b format might show the sync bits, data bytes and control

characters with the opposite ordering to that we use, such that “01” is listed as the sync bits for Data rather than

Control blocks. This can certainly be a source of confusion. It simply means that the opposite ordering was used by

the author: 0..66 rather than 66..0.

High Speed Serial Triggers and Decoders Instruction Manual

NRZ 80-bit Pattern Trigger Setup

Access the serial trigger dialogs:

lTouch the Trigger descriptor box or choose Trigger > Trigger Setup from the Menu Bar.

lTouch the Serial Type button, and the NRZ Pattern Standard button.

Then, working from left to right, make the desired selections from the NRZ Pattern dialog.

Source Setup

Caution: If using a differential probe, make sure the + side of the probe is connected to the + side of the

serial data signal. If using a cabled input, make sure the + side of the serial data signal is connected to the

trigger input. If this is not done, the input signal will be the inverse of what is expected, and the trigger will

not trigger properly. To correct this problem, either reverse the probe connections, or check the Invert box

next to the Source Channel indicator.

The bit rate can be computed from the acquisition data in many circumstances, but if the pattern is not random, the

bit rate may be miscalculated as a sub-multiple of the actual bit rate. For best results, enter a Bit Rate close to what

you expect for the serial data signal, then touch Compute Bit Rate.

If a serial data signal is detected but the bit rate does not match, an “unlocked” indicator will appear under the PLL

(phase-locked loop) label.

Once the bit rate is properly detected and the PLL locks onto the serial data signal, the “unlocked” indicator will

change to “locked.”

Equalizer

This selection is available only with the 6.5 Gb/s and 14.1 Gb/s triggers.

Very high frequencies, such as are found in serial data signals with speeds >5 Gb/s, may be highly attenuated as

they travel through a serial data channel, backplane, or printed circuit board. While Teledyne LeCroy offers tools (Eye

Doctor II, VirtualProbe) to software equalize the acquisition data, this does not help for triggering, since the hardware

Serial Trigger

trigger FPGA triggers on the oscilloscope acquisition datastream prior to any post-acquisition software equalization.

Therefore, we provide the capability to equalize in the trigger FPGA through the use of a Low (2 dB), Medium (5 dB),

or High (9 dB) equalization “boost.” Touch the HF Boost field, and make your selection from the pop-up menu.

Note: This equalization is applied only at the inputs of the trigger FPGA and is not displayed.

Encoding

This selection controls the way trigger patterns are entered and displayed:

Binary — Trigger pattern is entered and displayed as a sequence of 80 single-bit values.

Hex – Trigger pattern is entered and displayed as a sequence of 20 hexadecimal symbols.

Trigger Patterns

The trigger can be programmed with up to two 80-bit patterns, called Data Value 1 and Data Value 2. Touching the

corresponding field for either Data Value allows the desired trigger pattern to be entered on the Virtual Keypad pop-

up, in either Binary or Hex format (as selected in the “Encoding” section). “Don’t care” values (represented by an “X”)

may be entered at any point in the pattern.

Buttons on the right-hand end of the dialog allow the selected Data Value to be quickly set to all 1’s, all 0’s, all X’s, or

inverted from the current pattern.

To enable triggering on a Data Value, touch the corresponding Trigger On box to the left of the Data Value field. If

both Data Values are enabled, the oscilloscope will trigger when either Data Value 1 or Data Value 2 is detected in the

input data stream. The gray text above the Data Value 1 field indicates the current logical state of the trigger:

Selecting Highlight Pattern adds a green overlay to the trigger pattern on the NRZ waveform trace:

High Speed Serial Triggers and Decoders Instruction Manual

Linking Trigger and Decoder

A quick way to set up a serial trigger is to link it to a decoder by checking the Link to Trigger ("On") box on the Serial

Decode dialog. Linking trigger and decoder allows you to configure the trigger with the exact same values that are

used for decoding the signal (in particular the bit rate), saving the extra effort needed to re-enter values on the serial

trigger set up dialogs.

While the decoder and the trigger have distinct sets of controls, when the link is active, a change to the bit rate in the

decoder will immediately propagate to the trigger and vice-versa.

Serial Trigger

Using the Decoder with the Trigger

A key feature of Teledyne LeCroy trigger and decode options is the integration of the decoder functionality with the

trigger. While you may not be interested in the decoded data per se, using the decoded waveform can help with

understanding and tuning the trigger.

Stop and Look

Decoding with repetitive triggers can be very dynamic. Stop the acquisition and use the decoder tools such as

Search, or oscilloscope tools such as TriggerScan, to inspect the waveform for events of interest. Touch and drag

the paused trace to show time pre- or post-trigger.

Optimize the Grid

The initial decoding may be very compressed and impossible to read. Try the following:

lIncrease the height of the trace by decreasing the gain setting (V/Div) of the decoder source channel. This

causes the trace to occupy more of the available grid.

lChange your Display settings to turn off unnecessary grids. The Auto Grid feature automatically closes unused

grids. On many oscilloscopes, you can manually move traces to consolidate grids.

lClose setup dialogs.

Use Zoom

The default trigger point is at zero (center), marked by a small triangle of the same color as the input channel at the

bottom of the grid. Zoom small areas around the trigger point. The zoom will automatically expand to fit the width of

the screen on a new grid. This will help you to see that your trigger is occurring on the bits you specified.

If you drag a trace too far left or right of the trigger point, the message decoding may disappear from the grid. You

can prevent "losing" the decode by creating a zoom of whatever portion of the decode interests you. The zoom trace

will not disappear when dragged and will show much more detail.

Saving Trigger Data

The message decoding and the result table are dynamic and will continue to change as long as there are new trigger

events. As there may be many trigger events in long acquisitions or repetitive waveforms, it can be difficult (if not

impossible) to actually read the results on screen unless you stop the acquisition. You can preserve data concurrent

with the trigger by using the AutoSave feature.

lAutoSave Waveform creates a .trc file that copies the waveform at each trigger point. These files can be

recalled to the oscilloscope for later viewing. Choose File > Save Waveform and an Auto Save setting of Wrap

(overwrite when drive full) or Fill (stop when drive full). The files are saved in D:\Waveforms.

lAutoSave Table creates a .csv file of the result table data at each trigger point. Choose File > Save Table and an

Auto Save setting of Wrap or Fill. The files are saved in D:\Tables.

Caution: If you have frequent triggers, it is possible you will eventually run out of hard drive space. Choose

Wrap only if you're not concerned about files persisting on the instrument. If you choose Fill, plan to

periodically delete or move files out of the directory.

High Speed Serial Triggers and Decoders Instruction Manual

Serial Decode

The methods described here at a high level are used by all Teledyne LeCroy serial decoders, differing only slightly for

signals with an embedded clock and separate clock and data signals.

Bit-level Decoding

The first software algorithm examines the embedded clock based on a default or user- specified vertical threshold

level. Once the clock signal is extracted, the algorithm examines the traffic to determine whether a data bit is high or

low. The default High and Low levels are automatically determined from a measurement of the amplitude of the

signals acquired by the oscilloscope. Alternatively, they can be manually set by the user. 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.

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.

Logical Decoding

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 specific to the protocol (Header/ID, Address Labels, Data

Length Codes, Data, CRC, Parity Bits, Start Bits, Stop Bits, Delimiters, Idle Segments, etc.).

Message Decoding

Finally, another algorithm applies a color overlay with annotations to the decoded waveform to mark the transitions

in the signal. Decoded message data is displayed in tabular form below the grid. Various compaction schemes are

utilized to show the data for the duration of the acquisition, from as little as one serial data message acquisition to

many thousands. In the case of long acquisitions, only the most important information is highlighted, whereas with

the shortest acquisition, all information is displayed with additional highlighting of the complete message frame.

User Interaction

Your interaction with the software in many ways mirrors the order of the algorithms. You will:

lAssign a protocol/encoding scheme and data sources to one of the four decoder panels on the Serial Data and

Decode Setup dialogs. Each decoder can utilize different protocols or data sources, or have other variations,

giving you maximum flexibility to compare different signals or view the same signal from multiple perspectives.

lComplete the remaining subdialogs required by the protocol/encoding scheme. Once there is an acquisition in

buffer, you will see a result table and an annotation overlay on the waveform trace showing the decoded data.

lWork with the annotated waveform, result table and other functionality to analyze the decoding.

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LeCroy High Speed Serial Triggers User manual

LeCroy High Speed Serial Triggers User manual

LeCroy High Speed Serial Triggers User manual

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