DO-254 / ED-80 - Design Assurance Guidance for Airborne Electronic Hardware B-3.3.1: Appendix B 3.3.1 Elemental analysis

Elemental analysis measures verification completeness bottom-up: every functional element in the FFP, at the level the designer created it, is identified and its intended function verified by requirements-based tests meeting the Section 6 objectives; it suits designs whose detail is visible and controlled (ASICs, PLDs). Criteria define the elements and the coverage each needs, chosen per element type and complexity (primitive blocks (adders, counters, multiplexers, registers and the like) or interconnected groups), without going below the designer's level; vendor library functions can be handled as COTS with their application verified against the vendor description; for HDL designs the synthesised output is included and the synthesiser assessed; for PLDs the programmed content and feature use are analysed. Tests used come from target-assembly, standalone prototype, manufacturing acceptance (limited) or assessed post-layout simulation environments; a simulator used to measure completeness must be shown able to judge each element type, and translated stimuli checked. Unverified elements are resolved by improving tests (including repeatable responses to don't-care conditions), fixing requirements and adding tests, isolating or deactivating unused functions or showing no adverse effect, or bounding by analysis elements of no safety consequence. Output data identifies the FFPs, levels and coverage criteria (in the PHAC or verification plan), the methods, traceability from verification procedures to elements, tests and requirements added, and the completeness achieved with unresolved discrepancies and their rationale.