Abstract
Keywords Embedded Systems, Testing Methods, In-circuit Emulation, On-chip Debugging, Software Test
Abstract Nowadays control units in a motor vehicle are usually part of larger complex electronic systems which often have to accomplish safety relevant tasks. It is obvious which fatal consequences it can have if these systems are faulty. With the fast growing share of microcontrollers and the increasing safety requirements, the development methods and testing of the control software becomes of major importance.
A variety of tools are available to track down software faults. These tools mainly differ in the efficiency and the technology to find faults. For the so-called debugging (process of finding software faults) mainly in-circuit emulators are used. Other alternatives such as software debuggers usually do not conform with the high requirements in the automotive industries. However the tendency to use more and more 32-Bit microcontrollers running at high-frequencies pushes the possibilities of in-circuit emulation to its limits. New approaches for testing have to be found.
To counteract this development the microcontroller manufacturers have developed a new technology, called on-chip debugging. A variety of debugging functionalities are implemented directly on the microcontrollers. With external equipment the debug functionality is made accessible for the developer. Many different on-chip debug techniques have been developed. Such as OCDS, BDM, JTAG, OCE or NEXUS. These different approaches offer a wide range of debugging functionalities that has a strong impact on the testability of an embedded system. An outlook on the technology trends in this area and a detailed analysis of these differences will be outlined during this lecture. Test procedures like the dynamic software unit test round off the topic.