for CAN-FD/PN Transceivers iCC 2017 1 Content Standards and their - PowerPoint PPT Presentation

Interoperability challenges for CAN-FD/PN Transceivers iCC 2017 1

Content  Standards and their problems  Consequences for multi-supplier-solutions  Ways to achieve interoperability  Interoperability test specification for CAN & CAN-FD transceiver devices  Conclusion www.cs-group.de 2 communication & systems group

Standards and their problems Why are the standards created?  To improve quality  To facilitate innovation  To increase speed-to-market  To share development costs What is the main problem that often arises from standards?  The specification can be ambiguous  Specification is not clear enough  Leads to different interpretations Might it be a problem for my system? www.cs-group.de 3 communication & systems group

Consequences for multi-supplier-solutions It might be a problem for multi-supplier-solutions!  Different suppliers create products according to the same standard  The products shall interact in the same system  But! One single standard can be interpreted differently  Human language itself is ambiguous  A specified standard might contain coverage holes or missing details  The implementer might get something wrong or make a mistake www.cs-group.de 4 communication & systems group

System functionality with multi-supplier-solutions How to achieve system functionality in systems using multi-supplier-solutions? www.cs-group.de 5 communication & systems group

Ways to achieve interoperability a) Build up the intended system out of desired components and test it for a proper functionality  Sole appraisal : the desired components are working as expected within the certain system in a certain environment  Benefit : quite easy set up, by a simple mock-up  Disadvantage : each system, each option needs to be tested b)Check once the ability to interact with all combinations of devices  Disadvantage : Number of combinations increases rapidly with available implementations c) Run at first the conformance test and afterwards the general interoperability test (IOPT) for each implementation  Benefit : one conformance test + one interoperability test per device, each device usable in all systems www.cs-group.de 6 communication & systems group

Fundamentals of conformance testing “ Conformance testing is testing to determine whether a product or system meets some specified standard that has been developed for efficiency or interoperability.” – to be like specified – Fundamentals of conformance testing  To apply conformance testing, a specified standard must exist  This could be an international, national or company-specific standard  Different implementations of a standard are existing or planned  Conformance testing verifies whether an implementation represents the standard or not  The conformance test is the minimum requirement to guarantee interoperability www.cs-group.de 7 communication & systems group

Fundamentals of interoperability testing “ Interoperability is a property referring to the ability of diverse products or systems to work together (inter- operate).” – to be able to interact, to communicate – Fundamentals of interoperability  Interoperability is a property that is based on intended functional behaviour  Interoperability is relevant, if multiple entities shall inter-operate  Specified standards shall describe interoperable products and systems, i.e. the intended functional behaviour  Consequently, interoperability is the result of adherence of implementations to their specified standard www.cs-group.de 8 communication & systems group

IOPT – Test specification – Scope and aim Scope  Definition of test cases and test requirements to realize a test plan for the verification of CAN transceiver devices regarding their interoperability , even if provided by different manufacturers. Aim  Increase the probability of collaboration of CAN transceivers within a CAN system and increase the confidence level. Contrary to conformance tests, interoperability tests are based on a predefined reference environment . Single device measurements are not in focus of the interoperability tests. www.cs-group.de 9 communication & systems group

IOPT – Test specification – Addressed transceiver High-speed CAN transceiver types addressed by the test  Transceiver with and without bus wake-up capability  Transceiver with selective wake-up functionality  Transceiver with selective wake-up functionality tolerant to CAN-FD frames Bit rates in focus of the tests ≤ 1 Mbit/s 2 Mbit/s 5 Mbit/s Reference environment 5 Mbit/s reference environment 2 Mbit/s reference environment 500 kbit/s reference environment www.cs-group.de 10 communication & systems group

IOPT – Test specification – Network Ring communication Standard net test topology Ground shift [one node at a time] Bus failure injection Tests executed once in a homogeneous and once in a heterogeneous network with dedicated reference devices www.cs-group.de 11 communication & systems group

IOPT – Test specification – Focus of the tests Transceiver behaviour can be represented by a state machine  Transitions from one transceiver state to another represent reactions to certain events e.g. mode change, bus failures, ground shifts (or their combinations)  IOPT tests focus on the dynamical sequential behaviour  The interoperability tests verify the sequential behaviour of the transceiver in reference to the specified sequential behaviour  Observed and controlled at external points  Consideration of interoperability relevant phenomena  The verification happens on operation mode variation in combination with ground shift and bus failures www.cs-group.de 12 communication & systems group

IOPT – Test specification – Test cases  The test cases are based on operation mode transition from normal to low-power and the way back, which have to be ensured under all circumstances  Realized in 7 different test flows, with different logical bus failures injection point  Stress conditions covered by test cases  8 different bus failures  Ground shift of ± 1V » open wire on CAN high applied at each node » open wire on CAN low (one node at a time) » short circuit between CAN high and battery voltage  Local wake-up » short circuit between CAN low and battery voltage  Wake-up via bus » short circuit between CAN high and Ground » short circuit between CAN low and Ground initialized by each » disconnection of one terminating node node once www.cs-group.de 13 communication & systems group

IOPT – Test specification – Example test flow www.cs-group.de 14 communication & systems group

IOPT – Test specification – Overview of all views 7 test flows of the interoperability test system 5 flows with 16 sources for bus wake-up , 3 ground shift values applied at each node (one node at a time  33 scenarios) and 8 bus failures result in 21,120 test cases 2 flows with local wake-up only, 3 ground shift values applied at each node (one node at a time  33 scenarios) and 8 bus failures result in 528 test cases Furthermore the tests need to be executed twice , once in a homogeneous and once in a heterogeneous network with dedicated reference devices  43,296 single test cases with several verdict points each www.cs-group.de 15 communication & systems group

Conclusion  It is a fact that standardized specifications can be interpreted in different ways  This fact leads to having applications with similar but not equal behaviour  They must be interoperable!  How could this be prevented?  How to guarantee that different solutions will work together?  How could designers and customers ensure interoperable behaviour? Conformance + interoperability testing is the answer! www.cs-group.de 16 communication & systems group

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