Component-Based Safety Analysis of FPGAs

Component-based and modular software development techniques have become established in recent years. Without complementary verification and certification methods the benefits of these development techniques are reduced. As part of certification, it is necessary to show a system is acceptably safe which subsumes both the normal and abnormal (failure) cases. However, nonfunctional properties, such as safety and failures, are abstraction breakers, cutting across multiple components. Also, much of the work on component-based engineering has been applied to software-based systems rather than field programmable gate array (FPGA)-based systems whose use is becoming more popular in industry. In this paper, we show how a modular design embedded on a FPGA can be exhaustively analyzed (from a safety perspective) to derive the failure and safety properties to give the evidence needed for a safety case. The specific challenges faced are analyzing the fault characteristics of individual electronic components, combining the results across software modules, and then feeding this into a system safety case. A secondary benefit of taking this approach is that there is less uncertainty in the performance of the device, hence, it can be used for higher integrity systems. Finally, design improvements can be specifically targeted at areas of safety concern, leading to more optimal utilization of the FPGA device.