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Instruction Manual Automotive Protocols Trigger, Decode and Measure CANbus/CAN FDbus LINbus FlexRaybus Automotive Protocols Trigger, Decode and Measure Instruction Manual © 2015 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 duplicate and distribute Teledyne LeCroy documentation for their own internal educational purposes. Teledyne LeCroy is a trademark of Teledyne LeCroy, 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. 924311 Rev B July 2015 Contents About This Manual Assumptions Compatibility 2 2 2 About the Options About the CANbus and CAN FDbus Options About the LINbus Option About the FlexRaybus Option 3 3 4 4 Decoding Serial Decode Technical Overview Decoding Workflow Setting Up the Decoder CAN/CAN FD Decoder Settings LIN Decoder Settings FlexRay Decoder Settings Enabling/Disabling the Decoder Failure to Decode Reading Waveform Annotations Searching Waveforms Serial Decode Result Table 5 5 6 6 7 10 11 12 12 13 17 18 Measuring Graphing Measurements Using the Measure/Graph Dialog Filtering Serial Decode Measurements Using the Result Table Using the Decode Setup Dialog 24 24 25 26 29 29 Triggering Serial Trigger Technical Overview Linking Trigger to Decoder CAN/CAN FD Serial Trigger Setup LIN Serial Trigger Setup FlexRay Trigger Setup Using the Decoder with the Trigger Saving Trigger Data 30 30 30 31 35 37 40 41 FlexRay Physical Layer Testing General Settings Input Setup SI Voting Setup Eye Diagram Setup Mask Test Setup Physical Layer Measurement Setup 42 42 42 43 44 45 46 Contact Us 47 1 Automotive Protocols Trigger, Decode and Measure Instruction Manual About This Manual Teledyne LeCroy offers a wide array of toolsets for decoding and debugging serial data streams. These toolsets may be purchased as optional software packages, or are provided standard with some oscilloscopes. This manual explains how to use the following software: l CANbus Serial Trigger, Decoder, and Measurements (optional Symbolic) l CAN FDbus Serial Trigger, Decoder, and Measurements (optional Symbolic) l LINbus Serial Trigger and Decoder l FlexRaybus Serial Trigger, Decoder, and Physical Layer Tests Assumptions This manual is presented with the assumption that: l l l You have purchased and installed one of the serial data products described in this manual. You have a basic understanding of the 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 option is installed. Only features directly related to serial data triggering and decoding are explained in this manual. Compatibility Teledyne LeCroy is constantly expanding coverage of serial data standards and updating software. Some capabilities described in this documentation may only be available with the latest version of our firmware. You can download the free firmware update from teledynelecroy.com. While some of the images in this manual 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, as much functionality is shared. Product-specific exceptions will be noted in the text. 2 About the Options About the Options Decode Teledyne LeCroy decoders apply software algorithms to extract serial data information from physical layer waveforms measured on your oscilloscope. The extracted information is displayed over the actual physical layer waveforms, color-coded to provide fast, intuitive understanding of the relationship between message frames and other, time synchronous events. Trigger Trigger the oscillosocpe upon finding specific message frames, data patterns, or errors in serial data streams. Conditional filtering at different levels enables you to target the trigger to a single message or a range of matching data. Measure Add an optional set of serial data measurements to the oscilloscope's standard measurement capabilities and quickly plot the measurement results. Measurement data can be viewed as a Histogram, Track, or Trend plot of the digitally encoded data values for a specific input versus time. These plots effectively perform a digital-to-analog conversion that can be viewed right next to the decoded waveform. Measurements data can also be filtered to include only the specified frame types, IDs, or data patterns. As with all traces, you can set a gate to restrict measurements to a horizontal range of the grid corresponding to a specific time segment of the acquisition. About the CANbus and CAN FDbus Options CAN is a vehicle bus designed specifically for automotive applications, but it is now found in other applications, as well. The various CAN specifications are maintained by the International Organization for Standards (ISO) and can be obtained at www.iso.org. CANbus TD supports decoding standard CAN (11-bit and extended 29-bit). CAN FDbus TD supports decoding standard CAN as well as the advanced features of CAN FD: bitrate increase for the Data segment and the extension of the possible Data payload from 8 bytes to 64 bytes. It also supports ISO and non-ISO frames. Both options allow triggering on CAN messages, Frame IDs, serial data patterns, or errors. Frame-level and value-level filtering enable you to target the trigger to a certain type of CAN message, a single frame ID or data pattern, or to a range of data. The TDM variants of these options add a set of CAN-specific measurement parameters and plots. The TDM SYMBOLIC variants of these options add symbolic decoding, triggering, and measuring based on user-defined .DBC symbol files. 3 Automotive Protocols Trigger, Decode and Measure Instruction Manual About the LINbus Option LIN is a low-cost master/slave system designed for implementation in vehicles, typically in what is commonly referred to as body electronics. The LIN specification is maintained by the International Standards Organization (ISO) and can be obtained at www.iso.org. The LINbus TD option allows triggering on specific LIN frames, data patterns, or errors. Other features include: l l Ability to trigger and decode LIN Version 1.3, 2.x, and SAE J2602 formats, even when LINbus traffic contains mixed versions. Triggering on Checksum, Header Parity, and Sync Byte Errors. About the FlexRaybus Option FlexRay is an automotive network communications protocol developed by the FlexRay Consortium to govern on-board automotive computing. The FlexRay consortium disbanded in 2009, and FlexRay is now defined in ISO standards 17458-1 to 17458-5. The FlexRaybus TD option allows you to trigger and decode FlexRay protocol version 2.1 at 10 Mb/s, 5 Mb/s or 2.5 Mb/s. Features include: l l Ability to trigger on TSS, Frame characteristics, protocol Errors, or various Symbols (such as wakeup patterns). Frame triggers may be set on individual Frame IDs or ranges and be further conditionalized using Cycle Counts or Frame Qualifiers. The FlexRay PHY option also provides special physical layer eye diagram tests as specified by the FlexRay standard and physical-layer measurement parameters. 4 Decoding Decoding 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 between serial data signals that have a clock embedded in data and those with separate clock and data signals. Bit-level Decoding The first software algorithm examines the embedded clock for each message based on a default or userspecified vertical threshold level. Once the clock signal is extracted or known, the algorithm examines the corresponding data signal at the predetermined vertical level to determine whether a data bit is high or low. The default vertical level is 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. 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 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, whereas in the case of 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: l 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. l Complete the remaining dialogs required by the protocol/encoding scheme. l Work with the decoded waveform, result table, and measurements to analyze the decoding. 5 Automotive Protocols Trigger, Decode and Measure Instruction Manual Decoding Workflow We recommend the following workflow for effective decoding: 1. Connect your data and strobe/clock lines (if used) to the oscilloscope. 2. Set up the decoder using the lowest level decoding mode available (e.g., Bits). 3. Acquire a sufficient burst of relevant data, then run the decoder. NOTE: See Failure to Decode for more information about the required acquisition settings. 4. Use the various decoder tools to verify that transitions are being correctly decoded. Tune the decoder settings as needed. 5. Once you know you are correctly decoding transitions in one mode, continue making small acquisitions and running the decoder in higher level modes (e.g., Words). The decoder settings you verify on a few bursts will be reused when handling many packets. 6. 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. Setting Up the Decoder The main Serial Decode dialog allows you to preset up-to-four, independent decoders, Decode 1 to Decode 4. Each decoder can use different (or the same) protocols and data sources, or have other variations, giving you maximum flexibility to compare different signals or view the same signal from multiple perspectives. TIP: After completing setup for one decoder, 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. Controls with the same label on either dialog share the same function. 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 dialog. 2. On the same row as the Decode #: l Check On to enable the decoder now. This will let you view the decoding on screen as soon as there is an acquisition, which helps to begin tuning. If you wish, you can wait until all settings are complete to enable the decoder. l l Select the desired Protocol to use. Select the Data (Source) to be decoded. This can be any signal input channel (Cx), memory (Mx), or math function (Fx). 3. Optionally, check Link To Trigger On to tie the decoder setup to a serial trigger setup. 4. Touch the Setup button (next to Search) to open the Decode Setup dialog. If you use this method rather than the tab, your settings will be correctly pre-selected on the Decode Setup dialog. 5. Go on to complete the settings on the right-hand dialogs next to the Decode Setup dialog. 6 Decoding CAN/CAN FD Decoder Settings Symbolic Decoding If you have purchased the CAN TDM SYMBOLIC or CAN FD TDM SYMBOLIC options, some additional controls related to symbolic decoding will appear on the decoder set up dialogs. The default symbol file is located in D:\Applications\. You may copy your own symbol file to this directory and browse to it for easy selection. Symbol files must have the .dbc extension. We recommend that you copy and modify the default .dbc file to ensure the symbol file is properly formatted. Basic Right-Hand Dialog TDM SYMBOLIC users: choose to view the decoder results either in Hexadecimal or with Symbolic translation. If you choose Symbolic, touch Browse and select the Symbol File to use. NOTE: These controls will not appear if your installation does not support symbolic decoding. Enter the Nominal Bitrate (Arbitration bitrate) of the bus to which you are connected as precisely as you know it. The value should be correct within 5%. A mismatched bit rate will cause various confusing side effects on the decoding, so it is best to take time to correctly adjust this fundamental value. Use the Up and Down arrow buttons to scroll a list of standard bitrates, or touch the field to enter the value using the Adjust knob or the numeric keypad. TIP: If you are unsure of the bitrate, apply the Bit Rate measurement parameter to a short acquisition. CAN FD users: also enter the Data Bitrate. The same precautions apply as for the Nominal Bitrate. CAN FD users: check ISO if your signal supports ISO frames. Check Show Bits Idx to display a bit index for each bit, which can assist with analysis or debugging of the decode. The bit index starts at 0 at the beginning of the message and increases monotonously to the end of the message. Note that the bit index skips the stuffbits. Check Show Stuff Bits to display the stuff bits on each CAN message frame. 7 Automotive Protocols Trigger, Decode and Measure Instruction Manual Levels Right-Hand Dialog Enter the vertical Level used to determine the edge crossings of the signal. This value will be used to determine the bit-level decoding. Level is normally set as a percentage of amplitude, and defaults to 50%. It can alternatively be set as an absolute voltage by changing the Level Type to absolute. The set Level appears as a dotted horizontal line across the oscilloscope grid. If your initial decoding indicates that there are a number of error frames, make sure that the level is set to a reasonable value. Sampling Right-Hand Dialog This dialog only appears if your system supports CAN FD decoding. By default, ESI Dominant Only is selected, which indicates the signal always contains an ESI bit set to dominant. This allows the decoder to operate in a mode where it doesn't need sampling point information. When it is possible that signal can contain a recessive ESI bit, then enter the sampling point information manually. Clear ESI Dominant Only to enable the Nominal Bit Time and Data Bit Time fields and set the sampling rates. First, choose a Viewing style of either Basic (sampling position only) or Advanced (all fields). For the Basic setup, enter the sampling point as a percent of amplitude in the Requested Position fields. For the Advanced setup, manually enter values for: l Prop_Seg, the part of the bit time used to compensate for the physical delay times within the network. l Phase_Seg1 Number of time quantums before the sampling point. l Phase_Seg2 Number of time quantums after the sampling point. NOTE: All settings on this tab are ignored when decoding a Standard CAN frame. 8 Decoding Filter Right-Hand Dialog Use the Filter dialog to include only certain symbols or hex values in the decoder results. Choose a Filter Operator of: l l l In Range (include only those shown). In Range is very useful when working specifically on certain messages. It allows faster selection in the result table, as well as faster visual identification on the annotated trace and faster export to file. When working on messages that have a causal relationship (i.e., message 0xa6f is always expected sometime before message 0xb2c), filtering on ; will help in studying this traffic. Out Range (include all but those shown). Out Range helps when analyzing traffic dominated by one or a few messages. For example, in an elevator, the traffic might be constituted at 97 % by the position messages of the cabin traveling up and down. An engineer interested in the messages generated by passengers calling the elevator on the floors could filter out the frequent position messages and see only the comparatively rare floor requests. None turns off filtering. In Filter List, enter the list of symbols or hex values to include, separated by semi-colons. Clear Filter List resets the list. 9 Automotive Protocols Trigger, Decode and Measure Instruction Manual LIN Decoder Settings Basic Right-Hand Dialog Under Viewing, choose to view/enter data in either Binary or Hex(adecimal) formats. Enter the Vertical Level used to determine the edge crossings of the LIN signal. This value will be used to determine the bit-level decoding. Level is normally set as a percentage of amplitude, and defaults to 50%. It can alternatively be set as an absolute voltage by changing the Level Type to absolute. The set Level appears as a dotted horizontal line across the oscilloscope grid. If your initial decoding indicates that there are a number of error frames, make sure that the level is set to a reasonable value. Enter the Bitrate of the bus to which you are connected as precisely as you know it. The value should be correct within 5%. A mismatched bit rate will cause various confusing side effects on the decoding, so it is best to take time to correctly adjust this fundamental value. Use the Up and Down arrows to scroll a list of standard bit rates, or enter any value between 1and 20 kbit/s. TIP: If you are unsure of the bitrate, apply the Bit Rate measurement parameter to a short acquisition. Choose the LIN Version (standard) used to encode the input signal. If you are unsure or don't care, choose ALL. 10 Decoding FlexRay Decoder Settings Basic Right-Hand Dialog Adjust the Bitrate value to match the one on the bus to which you are connected. Touch the arrow buttons to scroll through standard bitrates (2.5, 5.0 or 10.0 Mb/s) and make a selection. Or, touch Bitrate and enter the value using the ADJUST knob or the pop-up keypad. Select the appropriate Channel to decode, Channel A or Channel B of the FlexRay bus. NOTE: Decoding will still occur when the wrong channel is selected, but results in CRC errors being shown on the overlay. Levels Right-Hand Dialog In Level High and Level Low, enter the signal crossing values. FlexRay is a tri-level signal and requires 2 levels for the oscilloscope to distinguish between 1 and 0. As indicated on the dialog, data transitions are valid only when crossing both Low and High levels. The set levels are shown by a dotted, horizontal line on the oscilloscope grid. NOTE: If the initial decoding contains a number of error frames, ensure level is set to a reasonable value. Level is normally entered as percent and defaults to 70% (of amplitude) for Level High and 30% for Level Low. You can alternatively enter Level as an absolute voltage value by changing the Level Type from Percent to Absolute. 11 Automotive Protocols Trigger, Decode and Measure Instruction Manual Enabling/Disabling the Decoder Once set up, the four decoders can be enabled simultaneously or separately, although this number may be limited depending on the type of source channels selected. Decoders can be easily disabled without disrupting the configuration. To enable: press the Front Panel Serial Decode button (if available on your oscilloscope) or choose Analysis > Serial Decode to open the Serial Decode dialog, then check Decode On next to the respective decoder. If View Decode is checked (default) for that decoder on the Decode Setup dialog, a result table and decoded waveform appear. The number of rows of data displayed on each table will depend on the Table#Rows setting. The default is one, which can be increased, but doing so will decrease the amount of the screen available to display traces. To disable: deselect the Decode On box individually, or touch Turn All Off. Failure to Decode Three conditions in particular may cause the decoder to fail, in which case a failure message will appear in the first row the the decoder result table, instead of in the message bar as usual: l l l Under sampled. If the sampling rate (SR) is insufficient to resolve the signal adequately based on the bit rate (BR) setup or clock frequency, the message "Under Sampled" will appear. 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. Too short acquisition. If the acquisition window is to short to allow any meaningfull decoding, the message “Too Short Acquisition” will appear. The minimum number of bits required varies from one protocol to another, but is usually between 5 and 50. Too small amplitude. If the signal’s amplitude is too small with respect to the full ADC range, the message “Decrease V/Div” will appear. The required amplitude to allow decoding is usually one vertical division. In each case, the decoding is turned off to protect you from incorrect data. Adjust your acquisition settings accordingly, then re-enable the decoder. NOTE: It is possible that several conditions are present, but you will only see the first relevant message in the table. If you continue to experience failures, try adjusting the other settings, as well. 12 Decoding Reading Waveform Annotations When a decoder is enabled, an annotated waveform appears on the oscilloscope display, allowing you to quickly read the results of the decoding. A colored overlay marks significant bit-sequences in the source signal. The overlay contains annotations corresponding to the Header/ID, Address, Labels, Data Length Codes, Data, CRC, Parity Bits, Start Bits, Stop Bits, Delimiters, Idle segments, etc. Annotations are customized to the protocol or encoding scheme. The amount of information shown on an annotation is affected by the width of the rectangles in the overlay, which is determined by the magnification (scale) of the trace and the length of the acquisition. Zooming a portion of the decoder trace will reveal the detailed annotations. TIP: An easy way to zoom is to touch the row number column of the result table. CAN Waveform Annotations These overlays appear on a CAN waveform or its Zoom trace (some annotations are not shown on the screen-shot). Annotation Overlay Color (1) (2) Overlay Text (3) Frame ID Navy Blue (behind other fields) Data Frame, ID= IDE Brick Red ID= DLC Green DLC= Payload Data Aqua Blue Data= CRC Royal Blue CRC= ACK Tan Error Bright Red (behind other fields) Error= 1. Combined overlays affect the appearance of colors. 2. Text in brackets < > is variable. The amount of text shown depends on your zoom factors. 3. Data values are shown in symbolic or hexadecimal depending on your decoder selection. Decoded waveform. At this resolution, little information appears on the overlay. 13 Automotive Protocols Trigger, Decode and Measure Instruction Manual Zoom of frame 0x200 showing annotation details. CAN FD Waveform Annotations These overlays appear on a CAN FD waveform or its Zoom trace (some annotations are not shown on the screen-shot). Annotation Overlay Color (1) Overlay Text (2) (3) Frame ID Navy Blue (behind other fields) IDE Brick Red ID = DLC Bright Green Payload Data Aqua Blue CRC Royal Blue CRC = ACK Tan EOF Aqua Blue EOF 1. Combined overlays affect the appearance of colors. 2. Text in brackets < > is variable. The amount of text shown depends on your zoom factors. 3. Data values are shown in symbolic or hexadecimal depending on your decoder selection. Initial decoding. Zoom of frame 0x700 showing annotation details. 14 Decoding LIN Waveform Annotations These overlays appear on a LIN waveform or its Zoom trace. Annotation Overlay Color (1) Overlay Text (2) (3) Message Navy Blue (behind other fields) Protocol error Bright Red (behind other fields) Breaks Grey Break Start/Stop bits Grey Synch bits Olive Green Synch= Message ID Brown Message Identifier = Parity bits Royal Blue Parity= Payload data Aqua Blue Data= Checksum bits Royal Blue 1. Combined overlays affect the appearance of colors. 2. Text in brackets < > is variable. The amount of text shown depends on your zoom factors. 3. Data values are shown in binary or hexadecimal depending on your decoder selection. Initial decoding. At this resolution, very little information appears on the overlay. Zoom of message 0x26. 15 Automotive Protocols Trigger, Decode and Measure Instruction Manual FlexRaybus Waveform Annotations These overlays appear on a FlexRaybus waveform or its Zoom trace to highlight key elements of the decoded signal (some annotations are not shown on the screen-shot). Annotation Overlay Color (1) Overlay Text (2) Message frame Navy (behind other fields) = , Cycle Count = Protocol error Bright Red (behind other fields) Transmit Start Sequence (TSS) and Channel Idle Delimiter (CID) Purple Frame Start Sequence (FSS) Orange Byte Start Sequence (BSS) Tan Frame ID Cyan Blue Payload data Aqua Blue Data Word = Slot ID Brick Red Slot ID = Payload Length (PL), Cycle Count (CC), and Frame End Sequence (FES) Green = Cyclic Redundancy Check (CRC) Royal Blue CRC = 1. Combined overlays affect the appearance of colors. 2. Text in brackets < > is variable. The amount of text shown depends on your zoom factors. Decoded FlexRay waveform. 16 Decoding Searching Waveforms Selecting the Search Action button on the Decode Setup dialog opens the decoder Search dialog, where you can enter criteria for finding events of interest in the waveform: various protocol elements, data values, errors, etc. Prev and Next buttons then navigate to matches found in the decoded waveform, simultaneously creating a zoom of each match. The default zoom always shows the matching data (plus any padding) at the full width of the grid. Use the standard Zoom controls to rescale the zoom to the desired level of magnification. CAN/CAN FD Search Options Choose the result table Column to Search for matching data. Enter the Value to find in that column. Check Use Value to enable this control. Optionally, enter a Left/Right Pad, the percentage of horizontal division around matching data to display on the zoomed waveform. Use the Prev and Next buttons to view the search results. LIN and FlexRay Search Options Next (Frame) ID finds the next occurrence of the ID entered in Value. Next Frame finds the start of the next frame. Next Error finds the next FlexRay protocol error. Use the Prev and Next buttons to view the search results. 17 Automotive Protocols Trigger, Decode and Measure Instruction Manual Serial Decode Result Table By default, a table summarizing the decoder results appears below the grids whenever a decoder is enabled. The result table provides a view of message data as decoded during the most recent acquisition, even when messages are too compact to allow annotation on the waveform trace. The table is displayed only when the View Decode checkbox is marked on the Decode Setup Dialog and a source signal has been decoded using that protocol. Selecting a number in the first (index) column of the table will display a zoom of the corresponding position in the decoded waveform. You can customize the result table, changing both the number of rows and the columns displayed. The default is one row. On a single-row table, touch the Down arrow at the far right to open a scrollbar that lets you display the previous or next row of data. NOTE: If a selected column is not relevant to the decoding selections, the column will not appear in the table. You can also export result table data to a .CSV file, and the table itself is useful for measuring. CAN Result Table Column Extracted or Computed Data Index (always shown) Number of the line in the table; also number of the message in the annotation overlay on the trace. Time Time elapsed from start of acquisition to Start of Frame. ID Standard or Extended Identifier bits (aka Frame ID). RTR Remote Transmission Request bits. DLC Real number of Data Length Code bytes (not the value encoded in the DLC). Data Data Field bytes. CRC Cyclic Redundancy Check sequence bits. ACK Acknowledge Field bit. Bit Rate/Msg Actual bitrate (BR) for this message, the average BR recomputed by dividing the entire Message time span by the total number of bits in the message. ID Length Number of bits in the ID of the CAN message, either 11 (Standard) or 29 (Extended). Section of typical CAN decoder result table. 18 Decoding CAN FD Result Table Column Extracted or Computed Data Idx (always shown) Number of the line in the table; also number of the message in the annotation overlay on the trace. Time Time elapsed from start of acquisition to Start of Frame. Format Number of ID bits, either 11 (Standard) or 29 (Extended). ID 11 or 29-bit message ID (ID of the message also governs its priority on the bus, based on the CSMA/CD scheme). IDE Arbitration Field Identifier Extension; Dominant (0) = 11-bit, Recessive (1) = 29-bit. EDL Extended Data Length bits. BRS Bit Rate Switch when Arbitration Frame and Data Frame configured to have different bit rate; Dominant (0) = no bit rate change, Recessive (1) = change to higher bit rate. ESI Error State Indicator; Dominant (0) = node is error active, Recessive (1) = node is error passive. RTR Remote Transmission Request bit. Dominant (0) = Data Frame; Recessive (1) = Remote Frame. It is only used in Standard CAN, not in CAN FD, but listed in case Standard CAN frames are included in the signal. It will appear empty for CAN FD frames. DLC Data Length Code bits. Data Data Field bytes. SBC Stuff Bit Counter. This column only appears when ISO frames are supported and ISO is checked. CRC Cyclic Redundancy Check Sequence bits. CL CRC Length, depending on the number of bytes in the payload either 17 bits for data frames up to 16 bytes or 21 bits for data frames over 16 bytes. BitRate Computed transmission bit rate. BR Data Data bit rate dynamically recomputed for every message, similar to the nominal BR. Status Description of all the errors in this message detected by the decoder. Section of CAN FD decoder result table. 19 Automotive Protocols Trigger, Decode and Measure Instruction Manual LIN Result Table Column Extracted or Computed Data Idx (always shown) Number of the line in the table; also number of the message in the annotation overlay on the trace Time Time elapsed from start of acquisition to Start of Frame Break Break (inter-message) bits Synch Synch bits ID Frame ID Parity Parity bits Data Length Data field length Data Data field bytes Checksum Checksum bits BitRate Transmission bit rate Symbol Status of any LIN symbols found in the frame Section of typical LIN result table. 20 Decoding FlexRay Result Table Column Extracted or Computed Data Index (always shown) Number of the line in the table; also number of the message in the annotation overlay on the trace. Time Time elapsed from start of acquisition to Start of Frame. Bit Rate/Msg Actual bit rate (BR) for this message, the average BR recomputed by diving the entire Message time span by the total number of bits in the message. Frame ID Frame identifier bits. Payload Length Number of words in data payload. Header CRC Cyclic Redundancy Check sequence bits. Cycle Count Cycle number. Data Data Field bytes. Trailer CRC Cyclic Redundancy Check sequence bits. Symbol Symbol type, if found: Wakeup Pattern (WUS), Channel Idle (CID), Collision Avoidance (CAS), or Media Access Test (MTS). Section of typical FlexRay result table. 21 Automotive Protocols Trigger, Decode and Measure Instruction Manual Customizing the Result Table NUMBER OF COLUMNS Follow these steps to change what data appears in the result table: 1. Press the Front Panel Serial Decode button or choose Analysis > Serial Decode, then open the Decode Setup tab. 2. Touch the Configure Table button. 3. On the View Columns pop-up dialog, mark the columns you want to appear in the table, clear any columns you wish to remove. Only those columns selected will appear on the oscilloscope display. To return to the preset display, touch Default. 4. Touch the Close button when finished. BIT RATE TOLERANCE On some decoders, you may also use the View Columns pop-up to set a Bit Rate Tolerance percentage. When implemented, the tolerance is used to flag out-of-tolerance messages (messages outside the userdefined bitrate +- tolerance) by colorizing in red the Bitrate shown in the table. NUMBER OF ROWS You may customize the size of the result table by changing the Table # Rows setting on the Decode Setup dialog. Keep in mind that the deeper the table, the more compressed the waveform display on the grid, especially if there are also measurements turned on. Zooming with the Result Table Besides displaying the decoded serial data, the result table enables you to quickly Zoom regions of the decoded waveform and access other functionality. Touching the Index (row) number in the first column opens a Zoom of the corresponding region in the decode trace. This is a quick way to navigate to events of interest in the acquisition. The Index column heading (top, left-most cell of the table header) bears the name of the corresponding protocol, and the cell's fill color matches the color of the input source. Touching this cell opens the Decode Setup dialog if it has been closed. Touching any other data cell in the table opens a pop-up menu with several choices of action: 22 l Off turns off the decode. l Zoom creates a zoom of the region where the data appears (same as touching the row number). l Setup opens the Decoder Setup dialog (same as touching the first column heading). l Export exports the decode results table to a .CSV file. l Measure displays a choice of measurements that can be made on the decoded signal. Decoding Exporting Result Table Data You can manually export the decoder result table data to a .CSV file: 1. Press the Front Panel Serial Decode button, or choose Analysis > Serial Decode, then open the Decode Setup tab. 2. Optionally, touch Browse and enter a new File Name and output folder. 3. Touch the Export Table button. Export files are by default created in the D:\Applications\ folder, although you can choose any other folder on the oscilloscope or any external drive connected to a host USB port. The data will overwrite the last export file saved in the protocol directory, unless you enter a new filename. In addition, the oscilloscope Save Table feature will automatically create tabular data files with each acquisition trigger. The file names are automatically incremented so that data is not lost. Choose File > Save Table from the oscilloscope menu bar and select Decode# as the source. Make other file format and storage selections as you wish. 23 Automotive Protocols Trigger, Decode and Measure Instruction Manual Measuring If you have installed any -TDM option or PROTObus MAG, these general measurements designed for debugging serial data streams can be applied to the decoded waveform. Measurements appear in a tabular readout below the grid (the same as for any other measurements) and are in addition to the result table that shows the decoded data. You can set up as many measurements as your oscilloscope has parameter locations. NOTE: Depending on the protocol, measurements may appear in a sub-menu of the Measure Setup menu and may have slightly different names. For example, the CAN sub-menu has measurements for CANtoValue instead of Message to Value, etc. The measurements are the same. Measurement Description View Serial Encoded Data as Analog Waveform Automatically sets up a Message to Value parameter and then tracks the assigned measurement. In doing so, a Digital-to-Analog Conversion (DAC) of the embedded digital data is performed and the digital data is displayed as an analog waveform. Message to Value Extracts and converts a specific portion of the data/payload in the message and displays it as an analog value. MsgToAnalog (Message to Analog) Computes time from start of first message that meets conditions to crossing threshold on an analog signal. Result is negative if analog event precedes message. You must choose the digital input in Source1 and the analog input in Source 2 for this measurement to work properly. AnalogToMsg (Analog to Message) Computes time from crossing threshold on an analog signal to start of first message that meets conditions. Result is negative if message precedes analog event. You must choose the analog input in Source 1 and the digital input in Source 2 for this measurement to work properly. MsgToMsg (Message to Message) Computes time difference from start of first message that meets conditions to start of next message. DeltaMsg (Delta Message) Computes time difference between two messages on a single decoded line. Time@Msg (Time at Message) Computes time from trigger to start of each message that meets conditions. BusLoad Computes the load of user-defined messages on the bus (as a percent). MsgBitrate Computes the bitrate of user-specified messages on decoded traces. NumMessages (Number of Messages) Computes the total number of messages in the decoding that meet conditions. Graphing Measurements Measure and graph options include simplified methods for plotting measurement values as: l l l 24 Histogram - a bar chart of the number of data points that fall into statistically significant intervals or bins. Bar height relates to the frequency at which data points fall into each interval/bin. Histogram is helpful to understand the modality of a parameter and to debug excessive variation. Trend - a plot of the evolution of a parameter over time. The graph's vertical axis is the value of the parameter; its horizontal axis is the order in which the values were acquired. Trending data can be accumulated over many acquisitions. It is analogous to a chart recorder. Track - a time-correlated accumulation of values for a single acquisition. Tracks are time synchronous and clear with each new acquisition. Track can be used to plot data values and Measuring compare them to a corresponding analog signal, or to observe changes in timing. A parameter tracked over a long acquisition could provide information about the modulation of the parameter. To graph a measurement, just select the plot type from the Measure/Graph dialog when setting up the measurement. All plots are created as Math functions, so also select a function location (Fx) in which to draw the plot. The plot will open along side the deocoding in a separate grid. Using the Measure/Graph Dialog The Measure/Graph dialog, which appears behind the Decode Setup dialog when measurements are supported, is a quick way to apply parameters specifically designed for serial data measurement and simultaneously graph the results. 1. Select the Measurement to apply and the Destination parameter location (Px) in which to open it. 2. The Source 1 decode is preselected; change it if necessary. If the measurement requires it, also select Source 2. 3. Optionally, choose a Graph format and the Destination math function location (Fx) in which to open it. 4. Optionally, set a measurement gate or filter. Touch Apply & Configure and make all required settings on the Measure right-hand dialogs that appear. NOTE: The Serial Decode measurements are also available from the standard Measure setup menu. You can use the that functionality to set up as many measurements as your instrument has parameters. 25 Automotive Protocols Trigger, Decode and Measure Instruction Manual Filtering Serial Decode Measurements After applying a measurement to the decoded waveform on the Measure/Graph dialog, set filter conditions on the right-hand dialogs that appear next to the Px dialogs. NOTE: Not all protocols or measurements support all filter types. Frame ID Filter This filter restricts the measurement to only frames with a specific ID value. 1. On the Main dialog, in Filter choose ID or ID+Data. 2. Open the ID tab that appears. 3. Choose to enter the frame ID value in Binary or Hex(adecimal) format. 4. Select the # Bits used to define the frame ID. (This will change the ID Value field length.) For CAN, choose from standard 11-bit or extended 29-bit. 5. Using the ID Condition and ID Value controls, create a condition statement that describes the IDs you want included in the measurement. To set a range of values, also enter the ID Value To. On the pop-up dialog that appears when you touch ID Value: l Use the Left and Right arrows to position the cursor. l Use Back to clear the previous character (like Backspace), Use Clear to clear all characters. Data Filter This restricts measurements to only frames containing extracted data that matches the filter condition. It can be combined with a Frame ID filter by choosing ID+Data on the Main dialog. Use the same procedure as above to create a condition describing the Data Value(s) to include in the measurement. Use "X" as a wild card ("Don't Care") in any position where the value doesn't matter. 26 Measuring Optionally, enter a Start Position within the data field byte to begin seeking the pattern, and the # Bits in the data pattern. The remaining data fields positions will autofill with "X". NOTE: For MsgtoMsg measurements, the data condition is entered twice: first for the Start Message and then for the End Message. The measurement computes the time to find a match to each set of conditions. Analog Filter This filter applies only to parameters that measure the decoded waveform relative to an analog signal: AnalogtoMsg and MsgtoAnalog. It allows you to set the crossing level and slope of the Analog signal event that is to be used in the measurement. Level may be set as a percentage of amplitude (default), or as an absolute voltage level by changing Level Is to Absolute. You can also use Find Level to allow the oscilloscope to set the level to the signal mean. The optional Hysteresis setting imposes a limit above and below the measurement Level, which precludes measurements of noise or other perturbations within this band. The width of the band is specified in milli-divisions. Observe the following when using Hysteresis: l l Hysteresis must be larger than the maximum noise spike you wish to ignore. The largest usable hysteresis value must be less than the distance from the Level to the closest extreme value of the waveform. 27 Automotive Protocols Trigger, Decode and Measure Instruction Manual Value Conversion Filter This filter applies only to the MsgtoValue parameter. It enables you to apply a value conversion to extracted data. The converted values appear in the result table. 1. CAN and CAN FD Symbolic Users: touch Browse DBC. Expand the .dbc file, then click on the desired symbol to filter on occurrences of that symbol. NOTE: This button will not appear if your installation does not support symbolic decoding. 2. Under Data to Extract, begin by entering the Start position and the # Bits to extract. 3. Choose the Encoding type if the signal uses encoding, otherwise leave it Unsigned. 4. Under Conversion, enter the a. Coefficient and b. Term that satisfy the formula: Value = Coefficient * Raw Value + Term. 5. Optionally, enter a Unit for the extracted decimal value. Holdoff, Gate, and Accept Certain measurements support holdoff, gating, or additional qualifiers (Accept). You will see the tab appear among the Measure set up dialogs when the function is supported. When applied to serial data measurement, these functions work exactly as they do elsewhere in the oscilloscope: l l l Holdoff specifies the amount of time or number of events to wait before starting the measurement. Gate specifies the Start Div and Stop Div that bound the portion of the acquisition to include in the measurement. Accept allows you to set qualifiers based on waveform state, either the measurement source or a second "gating" waveform, or to only accept measurement values that fall within pre-defined ranges. See the oscilloscope Operator's Manual or Getting Started Manual for more information. 28 Measuring Using the Result Table To quickly apply serial data measurements when the serial data setup dialogs are closed: 1. Touch any data cell of the decode result table. NOTE: If running more than one decoder simultaneously, be sure to select a cell from the correct table. The measurement source will be the waveform belonging to the table you touch. 2. From the pop-up menu, select Measure to display the Select Operation... dialog. 3. Touch any measurement operation to select it. 4. On the next dialog, choose a parameter location (P1-Px) in which to run the measurement. NOTE: If the location already stores a measurement, this selection will overwrite that setup. 5. To filter or gate the parameter, touch the Px cell of the readout table and make the desired settings on the right-hand dialogs that appear. Using the Decode Setup Dialog You can also access serial data measurements by touching the Measure button on the Decode Setup dialog. When using this button, measurements are set on the source of whichever Decoder (1-4) is currently selected on the Decode Setup dialog. 29 Automotive Protocols Trigger, Decode and Measure Instruction Manual Triggering Serial Trigger Technical Overview TD 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 scrutinises the data stream in real time to recognise "on-the-fly" the user-defined serial data conditions. When the desired pattern is recognised, the oscilloscope takes a real-time 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 concomittant data streams and analog signals. The serial trigger supports fairly simple conditions, such as "trigger at the begining of any packet," but the conditions can be made more restrictive depending on the protocol and the available filters, such as "trigger on packets with ID = 0x456". The most complex triggers incorporate a double condition on the ID and data, for example "trigger on packets with ID = 0x456 and when data in position 27 exceeds 1000". The trigger and decode systems are independant, although they are seamlessly coordinated in the user interface and the architecture. It is therefore possible to trigger without decoding and decode without triggering. Requirements Serial trigger options require the appropriate hardware (please consult support), an installed option key, and the latest firmware release. Restrictions The serial trigger only operates on one protocol at a time. It is therefore imposible to express a condition such as "trigger on CAN frames with ID = 0x456 followed by LIN packet with Adress 0xEBC." Linking Trigger to 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 decoder to trigger 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 distincts 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. 30 Triggering CAN/CAN FD Serial Trigger Setup To access the trigger setup dialog: l Touch the Trigger descriptor box or choose Trigger > Trigger Setup from the Menu Bar. l On the Trigger dialog, touch the Serial Type button, then the CAN Std or CAN FD Standard button. Working from left to right, make the desired selections from the CAN/CAN FD dialog. Source Setup In DATA, select the data source input channel. Use the Threshold control to adjust the vertical level for the trigger. Much like an Edge trigger, you must specify the level at which to process the incoming signal to determine whether the serial data pattern meets the trigger condition. TIP: One way to test that the threshold is set correctly is to initially set the Trigger Type to All. If you see a decoded message appear each time the oscilloscope triggers, the level is correct. Frame Type These controls appear only for CAN FD triggers. They allow you to specify information about the frame types to be found in the data stream. Choose whether the EDL bit Type is Both (X), CAN Std (0) only, or CAN FD (1) only. Both enables triggering on streams with mixed legacy and extended frame types. If using CAN FD Type, also: l l Check ISO Frame if the stream supports ISO frames. Choose a BR Select of Both (X), Normal (0), or FD (1). Both examines frames with or without a bit rate switch. Normal and FD examine only frames with the respective BRS bit values. CAN Setup If you have not linked the trigger to a pre-set decoder, enter the Nominal Bitrate used during the Arbitration sequence. NOTE: When the trigger is linked, this value is dynamically linked to the decoding bitrate; they are always the same. Use the Up and Down arrows to scroll the list of standard bit rates and make a selection, or touch Bitrate and use the Adjust knob or the pop-up keypad to enter the value. CAN FD users: also enter the Data Bitrate used during the Data sequence. 31 Automotive Protocols Trigger, Decode and Measure Instruction Manual Trigger Type These buttons determine which frames/fields are included in the trigger search: All triggers upon finding the first CAN frame. Remote triggers upon finding matching Frame ID values in Remote frames (only). Complete the Frame ID Setup described below. ID triggers upon finding matching Frame ID values in any type of frame. Complete the Frame ID Setup described below. ID+Data triggers upon finding matching Frame ID values and data patterns. Complete both the Frame ID Setup and Data Pattern Setup described below. Error triggers when a protocol error occurs. Select all the errors that can fire the trigger from below Error Type. Setup Format Choose to display/enter values in Binary, Hex(adecimal) or Sym(bolic) format. This selection propagates throughout the trigger setup. Toggling formats does not result in loss of information, but will transform the appearance of values. NOTE: SYMBOLIC users, follow the Symbolic Setup for Remote, ID, and ID+Data triggers instead of Frame ID Setup and Data Pattern Setup. Frame ID Setup Frame ID Setup is used to trigger upon encountering either a specific ID value or any value relative to a reference ID value (e.g., greater than x). Use these controls to create a condition statement that describes the trigger criteria. Choose the ID Condition (Boolean operator) that describes the relationship to the Frame ID value. To use a range of values, choose In Range or Out Range. In ID Bits, choose to trigger on 11-bit (Standard CAN) messages, 29-bit (Extended CAN) messages, or ALL. Enter the reference Frame ID value. When setting a range, enter the start Frame ID. When setting a range, enter the stop value in To Frame ID. Data Pattern Setup Create a condition statement that describes the Data field pattern upon which to trigger. This condition is added to the Frame ID condition. Choose the Data Condition (Boolean operator) that describes the relationship to the reference Data Value. To use a range of values, choose In Range or Out Range. Set DLC (Data Length Code) to any integer value from 0 to 8. It should match the DLC of the CAN message(s) on which to trigger. Choose from either Motorola (default) or Intel Byte Order. 32 Triggering Use Start Bit and # Data Bits together to define a string of up-to-64 contiguous data bits (8 data bytes) starting from any location in the CAN message data field (it is not limited to the start of a full byte or a nibble). The Start Bit can be any value from 0 to 63. The Start Bit value is always in LSB format (the bit number as shown on the decoded waveform, with bit 0 being at the far left and bit 63 being at the far right of the data string). Remember that the 1st data byte is bits 0-7, the 2nd data byte is bits 8-15, etc. Also, make sure the Start Bit value makes sense in relation to the DLC value (e.g., a Start Bit value of 32 with a DLC Value of 4 is not going to result in a successful trigger). The total # Bits can be any value from 1 to 64. Choose a Sign Type of signed or unsigned integer format. Enter the reference Data Value. When using a range, enter the start Data Value. For Hexadecimal format values, if desired, you can precede the ID value with 0x, but this is not necessary. Be sure to enter a Data Value that matches the DLC Value. When using a range, enter the stop value in Data Value To. Symbolic Setup Symbolic triggering sets the trigger conditions on values defined in a symbol file. Browse to and select the Symbol File. Touch the DBC button to view the selected symbol file. A pop-up dialog displays a hierarchy of Nodes, Messages, and Signals. Expand the list to see the values defined for each. Select the element on which to trigger, then touch OK. If you are setting up a symbolic ID+Data trigger, also create a condition statement that describes the data value upon which to trigger. All values that meet the condition will fire the trigger. l l Choose the Condition (Boolean operator) that describes the relationship to the reference value, then enter the Value. To use a range of values, choose In Range or Out Range and also enter the To value. NOTE: The Units assigned to the values are taken directly from the symbol file. 33 Automotive Protocols Trigger, Decode and Measure Instruction Manual Sampling Point This dialog appears behind the trigger dialog in CAN FD options. Use it to manually set the sampling point levels for the Nominal Bit Time and the Data Bit Time in cases where there may be a recessive ESI bit. NOTE: If the trigger is linked to a CAN FD decoder, these fields will already reflect the entries on the decoder Sampling right-hand dialog. Changing values here will also change the decoder. First, choose to use either Basic or Advanced Menu Format. In the Basic format, you need only set: l l The Requested Sampling Point position within the bit, expressed in %. Prop_Seg is forced to zero, while Phase_Seg1 and Phase_Seg2 are computed automatically. SJW (Synchronization Jump Width) The Advanced format disables the Requested Sampling Point and instead enables all the fields on the dialog for manually entering SJW as well as: l Prop_Seg, the part of the bit time used to compensate for the physical delay times within the network. l Phase_Seg1, number of time quantums before the sampling point. l Phase_Seg2, number of time quantums after the sampling point. In Advanced format, the Actual Sampling Point levels measured are displayed on the dialog when the trigger is enabled. 34 Triggering LIN Serial Trigger Setup To access the serial trigger dialog: l Touch the Trigger descriptor box or choose Trigger > Trigger Setup from the Menu Bar. l Touch the Serial Type button, and the LIN Standard button. Then, working from left to right, make the desired selections from the Trigger dialog. Source Setup In DATA, select the data source input channel. Use the Threshold control to adjust the vertical level for the trigger. Much like an Edge trigger, you must specify the level at which to process the incoming signal to determine whether the serial data pattern is meeting the set trigger condition. LIN Setup If you have not linked the trigger to a pre-set decoder, enter the Bitrate of the bus to which you are connected. This bit rate selection is dynamically linked to the decoding bit rate (they are always the same value). Use the Up or Down arrows to scroll the list of standard bit rates and make a selection, or touch the control and enter the value as close as possible to the actual bus rate. Trigger Type The LIN trigger can be configured to fire upon simple Start of Frame (Break), a Frame ID value, a combination of Frame ID values and Data patterns, or LIN error. Choose the desired Trigger Type and complete the remaining fields required to set the trigger condition: l Error, complete the Checksum Error Setup below. l Frame ID, complete the Frame ID Setup below. l ID + Data, complete both Frame ID Setup and Data Pattern Setup below. Setup Format Choose to display/enter values in Binary or Hex(adecimal) format. The selection propagates throughout the entire trigger setup. Toggling between formats does not result in loss of information, but will transform the appearance of values. Frame ID Setup Frame ID Setup is used to trigger upon encountering either a specific ID value or any value relative to a reference ID value (e.g., greater than x). Use these controls to create a condition statement that describes the trigger criteria. 35 Automotive Protocols Trigger, Decode and Measure Instruction Manual Choose the ID Condition (Boolean operator) that describes the relationship to the Frame ID value. To use a range of values, choose In Range or Out Range. Enter the reference Frame ID value. When setting a range, enter the start Frame ID. When setting a range, enter the stop value in To Frame ID. Data Pattern Setup Create a condition statement that describes the Data field pattern upon which to trigger. This condition is added to the Frame ID condition. Choose the Data Condition (Boolean operator) that describes the relationship to the reference Data Value. To use a range of values, choose In Range or Out Range. Enter the reference Data Value. When using a range, enter the start Data Value. In Hexadecimal format, data must be entered as full bytes even though the minimum required acceptable entry is a nibble. If less than a full byte is entered, then a "don't care" (wildcard) X precedes the pattern values entered. Up to 8 bytes of data can be entered as a pattern value. If less than 8 bytes of data is entered for the pattern value, the data is assumed to begin at Data Byte 1 in the LIN message. If this is not desired, then add preceding or trailing X nibbles to the pattern value. When using a range, enter the stop value in Data Value To. # Data Bytes defaults to the length, in bytes, of the pattern set in the Data Value. If you change the length to be less than this value, it would truncate the beginning of the pattern value. If you were to increase the pattern length, it would add "don't care" XX byte values to the beginning of the pattern value. The maximum number of data bytes is 8, per the LIN standard. Checksum Error Setup Enter the Error Frame ID to search. Check all the error types on which to trigger: Checksum Error, Header Parity, or Sync Byte. If Checksum Error is selected, also enter the LIN Spec. (standard) used to encode the data and the # Data Bytes in a message. 36 Triggering FlexRay Trigger Setup To access the serial trigger dialog: l Touch the Trigger descriptor box or choose Trigger > Trigger Setup from the Menu Bar. l Touch the Serial Type button, and the FlexRay Standard button. Then, working from left to right, make the desired selections from the Trigger dialog. Source Setup These controls are use by all trigger types. In DATA, select the data source input channel. Use the Threshold controls to set the High and Low vertical level for the trigger. Much like an Edge trigger, you must specify the level at which to process the incoming signal to determine whether the serial data pattern is meeting the set trigger condition. FlexRay is a tri-level signal and requires two voltage threshold settings which enable the oscilloscope to distinguish between 1 and 0. If desired, use the Find Threshold button to set appropriate thresholds based on the input signal characteristics. FlexRay Setup If you have not linked the trigger to a pre-set decoder, enter the Bitrate of the bus to which you are connected. This value is dynamically linked to the decoding bitrate; they are always the same. Touch the arrow buttons to scroll through standard bitrates (2.5, 5.0 or 10.0 Mb/s), or touch Bitrate and enter the value using the Adjust knob or the pop-up keypad. Trigger Type The LIN trigger can be configured to fire upon the occurrence of a simple Transmit Start Sequence (TSS), a Symbol, various Frame characteristics (ID, Cycle Count, or Qualifiers), or a FlexRay error. Choose the desired Trigger Type and complete the remaining fields required to set the trigger condition: l TSS, complete Setup Format below. l Frame, complete Setup Format and Frame Trigger below. l Symbol, complete the Symbol Trigger below. l Error, complete Error Trigger below. Setup Format Choose to display/enter values in Binary or Hex(adecimal) format. The selection propagates throughout the entire trigger setup. Toggling between formats does not result in loss of information, but will transform the appearance of values. 37 Automotive Protocols Trigger, Decode and Measure Instruction Manual Frame Trigger Setup FRAME ID Frame ID Setup is used to trigger upon encountering either a specific ID value or any value relative to a reference ID value (e.g., greater than x). Use these controls to create a condition statement that describes the Frame ID criteria. Choose the Condition (Boolean operator) that describes the relationship to the Frame ID value. To use a range of values, choose In Range or Out Range. Enter the reference Value. When setting a range, enter the start Frame ID in Value and the stop Frame ID value in To. TIP: Use X as a wildcard ("Don't Care") in any position. To effectively exclude the Frame ID as a trigger condition, choose the Equal condition and the default value of all Xs. CYCLE COUNT The Cycle Count is a decimal value between 0 and 63 correlating to the FlexRay Cycle Count numbering system. The default Cycle Count is 0. You may also specify a Repetition Factor to allow for triggering when Cycle multiplexing is being used. This condition is added to any Frame ID conditions. As with Frame ID, create a Boolean statement describing the Cycle Count criteria. Omit the Cycle Count criteria by selecting Condition "Don't Care". When the Cycle Count condition is set to Equal, set a Repetition Factor of 1, 2, 4, 8, 16, 32 or 64. FRAME QUALIFIERS Defined in the FlexRay specification, the occurrence of Payload Preamble, Null Frame, Sync Frame, or Startup Frame bits may be set as trigger conditions. These conditions are added to any Frame ID or Cycle Count conditions. Each qualifier can be set to one or zero, or omitted by selecting "Don't Care". The trigger will be restricted to frames with matching values in the respective field. 38 Triggering Symbol Trigger Setup A Symbol trigger fires upon finding any frame that includes any one of the selected symbols. Mark all the desired symbol types. Error Trigger Setup An Error trigger fires upon the occurence of any FlexRay protocol or CRC error. Mark all the desired error types. If you choose Payload CRC, also select the Payload input channel. 39 Automotive Protocols Trigger, Decode and Measure Instruction Manual 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 view 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: l l l Increase the height of the trace by decreasing the gain setting (V/Div) of the source channel. This causes the trace to occupy more of the available grid. Change 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. Close 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 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. 40 Triggering 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 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. l l AutoSave 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. AutoSave 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. 41 Automotive Protocols Trigger, Decode and Measure Instruction Manual FlexRay Physical Layer Testing The FlexRaybus PHY option include physial layer tests specified by the FlexRay standard. When these options are activated, an additional FlexRay Phy dialog appears following the Measure/Graph Setup tab. The dialog contains selections for SI Voting, Eye Diagram, Mask Testing, and Measurement Setup to quickly align signals to the FlexRay specification. These tests can be run simultaneously with the protocol-level decoding to quickly identify where errors and anomalies occur. General Settings Mark Enable to enable physical layer testing. Mark Show Decode to display the signal decoding during the physical layer test. The current FlexRay decoder settings from the Decode Setup dialogs will apply. The Decode Setup button provides quick access to the Decode Setup dialog. Input Setup Touch Source 1 and choose the transmitter test signal. NOTE: The Source 1 signal is used for SI Voting, Eye Diagram, and Mask Test functions. Source 1 and 2 are both used for the Measurement function. Optionally, touch Source 2 and choose the receiver test signal for Physical Layer Measurements. Enter the Bitrate as close as possible to the the bitrate of the bus to which you are connected. Use the arrows to scroll through the standard bitrates (2.5 Mb/s, 5 Mb/s and 10 Mb/s) and make a selection, or touch the field to enter the value using the ADJUST knob or the keypad. NOTE: Eye diagrams can be created from FlexRay waveforms with bitrates of 2.5 Mb/s, 5 Mb/s and 10 Mb/s as defined in the FlexRay standard. 42 FlexRay Physical Layer Testing SI Voting Setup SI Voting was developed as an alternative for users who found eye diagrams and masks to result in failed tests on signals which would actually pass in practice. SI Voting filters every bit pattern of the form 00010 and 11101 (i.e., all single-bit pulses), then measures the bit-length between a point on the first edge and a symmetrical point on the second edge, providing a set of time deltas between the two edges. The result is then tested against the specification constraints on shortest and longest acceptable bitlength, maximum acceptable bit-length variation, longest acceptable edge time, and top and base levels. NOTE: SI Voting disables the application and display of FlexRay physical layer measurements. Mark SI Voting On to enable voting. Mark each item on which to vote: l Pos. Bits Length l Neg. Bits Length l Filtered Input 43 Automotive Protocols Trigger, Decode and Measure Instruction Manual Eye Diagram Setup Eye diagrams are created by slicing the bits transmitted in the FlexRay signal and superimposing each bit on to an eye diagram. The signal is sliced based on measurements taken at the falling edge of the first Byte Start Sequence (BSS) and the time between consecutive BSS symbols. These measurements allow the algorithm to compute the rate of the embedded clock and slice the FlexRay waveform in to subwaveforms that are one bit in length. The clock uses a constant bitrate specified by the user and is resynchronized on every BSS. These sub-waveforms are then scaled to fill 8 horizontal divisions on the oscilloscope and represent 1 Unit Interval (UI) in the eye diagram and superimposed on top of each other. The resulting Eye Diagram behaves as detailed in the FlexRay specification (Electrical Physical Layer Application Notes, Chapter 2.19) and produces an eye of all the bits in a message by synchronizing on the BSS transition. Then, it uses a constant clock to slice bits up to the next BSS. Masks are defined for 2.5, 5.0, and 10 Mb/s speeds. Mark Eye Diagram On to enable eye diagramming. NOTE: It will take more time to generate an eye diagram from long acquisitions than from short ones. Mark Eye Violation to display violations. Mask violations appear as red failure indicators where the eye digram intersects the mask. Mark Stop on violation to stop the acquisition whenever am eye diagram violation occurs. This will allow time to examine the decoding compared to the eye diagram violation and understand exactly where the violation occurred. 44 FlexRay Physical Layer Testing Mask Test Setup Mask testing can be performed on the eye diagram with masks defined at TP1 and TP11. The mask is aligned horizontally by computing the time for a single UI and centering it on the display. The mask is centered vertically around 0V. As explained in the FlexRay Electrical Physical Layer Specification, Chapter 7, the mask test makes an eye of the bits following any transition (rising and falling) with no clock recovery. Only a 10 Mb/s mask is defined in the specification, but assuming a controller passing at 10 Mb/s also passes at other bitrates, other masks are provided for different test points and setup configurations. Mark Mask Test On to enable the mask test. Mark Mask Violation to show violations on the display. Mask violations appear as red failure indicators where the eye digram intersects the mask. Mark Stop on violation to stop the acquisition whenever a mask violation occurs. This will allow time to examine the decoding compared to the mask violation and understand exactly where the violation occurred. Touch Mask Type and choose from: l TP1 l TP1 Bus Driver l TP11 l TP11 Active Star 45 Automotive Protocols Trigger, Decode and Measure Instruction Manual Physical Layer Measurement Setup You can apply four measurements defined in the FlexRay physical layer specification to characterize the timing properties of the signal along the communication channel. Results appear in the measurement readout table below the grid. Clear SI Voting On to enable measurement selection. Mark each measurement you wish to apply to the test signal: l l l l Propagation Delay, measured on two points along the communication channel from the emitter node module to the receiver node module. Propagation Delay characterizes the propagation time of the signal using the first transition of the Byte Start Sequence (BSS). Assymetric Delay, measured on two points along the communication channel from the emitter node module to the receiver node module. Assymetric Delay characterizes the difference in delay between rising and falling edges. Frame TSS Length Change, measured on two points along the communication channel from the emitter node module to the receiver node module. Frame TSS Length Change measures the change in width of the Transition Start Sequence (TSS). Jitter, measured on a single point, usually the receiving node. Jitter measures the change of length betwee the last BSS and the FSS. This should usually be 1µs. Touch Probed On and choose the type of line you are measuring: 46 l BP-BM (diff) - a differential signal on the communication channel l RxD-TxD (dig.) - a two-level digital signal in the communication controller intrface. Contact Us Contact Us Our regional service centers are: World Wide Corporate Office Teledyne LeCroy 700 Chestnut Ridge Road Chestnut Ridge, NY, 10977, USA teledynelecroy.com Sales and Service: Ph: 800-553-2769 / 845-425-2000 FAX: 845-578-5985 contact.corp@teledynelecroy.com Support: Ph: 800-553-2769 support@teledynelecroy.com US Protocol Solutions Group Teledyne LeCroy 3385 Scott Boulevard Santa Clara, CA, 95054, USA teledynelecroy.com Sales and Service: Ph: 800-909-7211 / 408-727-6600 FAX: 408-727-0800 protocolsales@teledynelecroy.com Support: Ph: 800-909-7112 / 408-653-1260 psgsupport@teledynelecroy.com European Headquarters Teledyne LeCroy SA 4, Rue Moïse Marcinhes Case postale 341 1217 Meyrin 1 Geneva, Switzerland teledynelecroy.com/europe Ph: + 41 22 719 2111 FAX: + 41 22 719 2230 contact.sa@teledynelecroy.com China LeCroy Corporation Beijing Rm. 2001, Unit A, Horizon Plaza No. 6, Zhichun Road, Haidian Dist. 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