STP 2 concept: a functional safety approach, grounded in IEC 61508, for the definition, design, and implementation of a two-out-of-two (2oo2), dual Field Programmable Gate Array-based architecture. It covers the development of a SIL 4 processing platform — a particularised instantiation of the generic safety requirements expressed by the standard and its derivatives. Validated through the ISO 26262 V-model and demonstrated through a hardware prototype implementing the SPHINXS protocol for cross-synchronisation and exchange of safety-critical data.