Low-Response-Time PC Interface for Real-Time Analysis of Embedded Systems

Abstract

Automotive industries are constantly increasing the number of electronically controlled units in a vehicle to provide performance, comfort and extra features to the user. Com- munication between these different electronic devices commonly occur through the Controller Area Network (CAN) bus. Due to the presence of a large number of nodes in the network, testing different nodes can be cumbersome. So to make the testing and verification efficient and precise, a system that acts as an interface between a Personal Computer (PC) and the CAN network has been designed in this project. Since CAN messages can be scheduled within 1 ms time frames at maximum baud rate, the response time of this interface must be of the same order to avoid missing any messages. With the help of this interface, specific test sequences can be injected to a particular node and the response can be observed. It can also be used to monitor the messages in the network at frame level. A prototype of such an interface has been designed and implemented using STM3240G-Eval Evaluation board. Ethernet and Universal Serial Bus (USB) are used as the physical interface between PC and Microcontroller. An evaluation of different physical interfaces were performed and it was found that Ethernet had a response time of 0.4 ms making it suitable for this application. On the other hand USB in high-speed mode had a very low response time of 0.08 ms and so can be used for applications that require very high performance.