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MOST Compliance and Quality

Reliable Diagnostics of a MOST System

21. Mai 2013, 14:09 Uhr | Dr. Terezia Toth

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Fortsetzung des Artikels von Teil 1

Electrical control line in a MOST network

ECL is limited to MOST systems with a maximum of 20 devices. Each device gets a unique node class in the system. Each node class has a result slot in the test result sequence. Each result slot has two parameters: “En” and “On”, where n is the node class. En=1 indicates that the device is not alive or the test is not supported. “On” is the MOST signal result.
An electrical wake-up impulse (EWU) defines the start of an electrical wake-up without a system test. With a single EWU, the wake-up has to be triggered by the falling edge of the first impulse. Electrical wake-up repetitions are called a multiple EWU.
If implemented, the optional ECL feature must be compliant with the ECL Specification [1] of the MOST Cooperation. Compliance with the specifications is one major element for the success of MOST technology. To ensure it, the MOST Cooperation released the “MOST Extended Core Compliance Test Specification: Electrical Control Line” in July 2012 [2]. Depending on the functionality of the device under test (DUT), the corresponding features have to be tested while the other roles have to be simulated. On the one hand the tester has to simulate the ECL sequences of the initiator or the participant, depending on the DUT. On the other hand the tester has to evaluate the received sequences.
The testing process shall be flexible enough to handle this diversity of options and requirements. The challenge is to test not only the good case but also the bad cases with fault injection.
On the one hand the tests have to be reliable, without oversights, mistakes, or other chances of human error. The test specification has to be easily readable and understandable. The execution shall be independent of the area where the test takes place, at a MOST Compliance Test House (MCTH) or at a supplier’s in-house test lab. Global consistency regarding test results has to be ensured. On the other hand the effort has to be limited. The test process shall not be costly and time-consuming but provide results fast.