The ECUs of a modern car are all linked together via various networking technologies like CAN, LIN or even FlexRay for safety critical applications. In the case of infotainment and multimedia systems, MOST has established itself as the de-facto standard, distinguished by high bandwidth and electrical robustness. MOST150, its third generation, makes high demands on automotive developments and testing environments. This article puts the focus on manufacturing, burn-in/run-in test, and reliability testing of ECUs implemented with a MOST interface. The upcoming problems for hardware, industrial standards and test strategies, and the methods for dealing with them will also be discussed.
Test system must accurately simulate real environment
To test the functions of a MOST ECU, it must be installed in a realistic vehicle environment to provide the input and output information it needs to perform its control tasks. Therefore, the test system must accurately simulate the vehicle environment. In the majority of cases, an ECU with MOST interface has a number of different communication interfaces other than MOST that have to be supported. One reason could be that the ECU has to act as a gateway and/or system components are combined into one unit.
An important issue in managing the industrial environments is to consider the established standards used for the hardware that is simulating the MOST interface. Especially for hardware, the standards are restricted to interchangeable components and to hardware setups that are easy to expand. USB and Ethernet interfaces are not suitable due to poor reliability in hostile environments and long duration tasks. An often-used standard for such measurement and simulation systems is the PXI bus (PCI eXtensions for Instrumentation). Using PXI takes advantage of a robust, PC-based, and high-performance measurement and automation system. With PXI, the benefits of low cost, performance, flexibility, and a wide range of available cards form the basis of a multiplicity of test systems. So clearly the MOST appropriate solution, where possible, is to use PXI cards to provide the MOST interface.
Among the technical facts to ma- nage the tests of MOST communication and peripheral hardware conditions, some tests enforce simultaneous control of a quantity of DUTs (Device Under Test), e.g. reliability or long duration tests of several hours and days. To perform this method of testing, a modular structured system has to correlate with the abilities of the MOST networking architecture for the case of homogeneous DUTs.