How to test and validate the new isochronous and IP/Ethernet features of MOST150 Testing the New Capabilities

MOST150 test setup: MOST PCI Tool Kit, OptoLyzer G2, Automotive Test System and OS81110 evaluation board.
Figure 1. MOST150 test setup: MOST PCI Tool Kit, OptoLyzer G2, Automotive Test System and OS81110 evaluation board.

In addition to the classic audio applications, the latest MOST generation enables high-performance packet and video applications in vehicles. Higher bandwidth and additional transmission mechanisms are available with MOST150 and make the applications mentioned above possible. All the new features and capabilities can be experienced easily with existing MOST150 tool solutions. Tailor-made evaluation platforms simplify the implementation of custom applications; various tool solutions for transmitting data via the new isochronous channels as well as via the Ethernet channel on MOST150 are available. Test engineers can now benefit from new possibilities with MOST150 network analysis and monitoring.

For the car buyer, a failure-free operation of the vehicle is mandatory. For this reason, carmakers insist on high reliability and quality for all the electronic control units (ECU) and systems in the vehicle. For safety reasons, the carmakers and their device- and sub-suppliers have installed test processes along the complete supply chain. Measures for safeguarding the devices and systems are considered during the creation of specifications, via design and implementation, and up to validation, verification, and integration of devices into the systems.  In order to implement these processes in the infotainment domain as well, specific tool solutions are available which also incorporate features to test MOST ECUs.

These tools are typically divided into test & simulation tools and analysis & verification tools. The test & simulation tools primarily offer the ability to run initial tests of newly implemented features during the development phase. Therefore, such tools send control message data via the network to the device under test (DUT), or they might fill packet data and audio/video streams onto MOST to be sent to the DUT. Adding more features and capabilities to such simulation setups can create full MOST device simulations or rest bus simulations. These simulations typically act as counterparts to the DUT and the developer can check whether the DUT works correctly with the simulated devices. The analysis and verification tools mainly monitor and display the communication between the devices in a MOST network on all channels in order to quickly and efficiently identify issues, failures, and misbehaviour. All these features and how they can be used are explained in the following sections by means of a typical test setup containing MOST150 tool solutions. This setup is shown in figure 1 .  

Standard tool requirements   

The injection of control, packet, and streaming data has been an important use case since the early days of MOST. Therefore, a lot of tool solutions for MOST25 and MOST50 offer comprehensive support in this respect and first solutions for MOST150 are already available on the market. In general, test & simulation tools provide data injection capabilities, where the injection of audio and video data is crucial.  A solution covering this in a very simple way is the MOST PCI Toolkit from SMSC, which equips any standard PC with a MOST interface. The included driver set installs various drivers into the Windows operating system. The audio driver, as one part of the driver set, installs for example up to eight MOST audio interface devices (four for receiving, four for recording).

This way, standard audio player software such as WinAmp can send audio data easily from the PC to the MOST network. The player software just needs to use the installed MOST audio interfaces, and when the user pushes the play button in the player software (figure 2), the audio stream is sent to the MOST network. An audio-related DUT in the MOST ring, such as an amplifier, can easily be tested with regard to the audio features by running such test procedures. This enables the user to run multiple types of tests with- out the need to put a real audio source device (e.g. a DVD Player) into the test setup. Test & simulation tools may extend such use cases up to real device and rest bus simulations. Analysis & verification tools display the complete message and data traffic on the MOST bus, which eases the identification of error situations and atypical behaviour in a very efficient way. While the functionality of such tools has remained consistent, the presentation of the monitored data has improved significantly in recent years. In addition to the standard method of displaying the data in a chronological sorted viewer list showing all messages, including all parameters (e.g. pre-emptive acknowledge), there are also software solutions available that provide a graphical representation of the data. MOST System Radar, for example, shows all details of the communication in a MOST system, including the logical order of devices in the MOST ring, the communication paths or the amount of messages per node. This way the user can easily find potential issues within the system. In addition, relevant aspects affecting the MOST nodes will be displayed, such as the logical node address or the FBlock IDs residing in the node. This provides a system overview and as well helps to identify errors quickly.