Verification of Robustness for FPGAs and CEH to meet DO-254 & FAA Order 8110.105 Objectives
The verification of Robustness is conceptually simple, once the reasonable set of “abnormal operating conditions” has been established. During testing those conditions are created and the FPGA/CEH response is noted. Depending upon system requirements, sometimes the FPGA/CEH response need not be “to work normally” but should at a minimum return to normal operation once normal conditions are reestablished. Part of the analysis is to establish acceptable FPGA/CEH responses to the “abnormal operating conditions”. Some of the acceptable responses may actually affect the LRU/CCA hardware performance or software functions hosted on the system, an early identification of such interdependence is essential for the planning of robustness testing.
The test cases implementing robustness testing conform to the same constraints and pedigree as any requirements based test case. The key here is to know the scope of the tests and plan accordingly. The understanding that the test environment will need to be capable of generating these “abnormal operating conditions” is key to properly planning for and establishing the infrastructure needed. Attempting to modify or adapt a Test Infrastructure later in the life cycle is never beneficial as there is limited success with regard to effectiveness, time and costs.
This white paper introduces the reader to a set of methodologies for understanding, identifying, and addressing the Verification of Robustness within FGPA/CEH devices.
The understanding and identification of FPGA/CEH component robustness is described as the ability of the FPGA/CEH to tolerate or respond to abnormal operating conditions. In practice, this description is somewhat open-ended. This paper establishes a reasonable boundary or limit for defining the abnormal operating conditions and how to account for them.
The discussions and examples presented here are not representative of the only methodology which will address the Verification of Robustness. They should be used as a guide to establishing processes and policy which integrate with your resources and documentation.