Fine-grained module-based error recovery in FPGA-based TMR systems

Space processing applications deployed on SRAM-based Field Programmable Gate Arrays (FPGAs) are vulnerable to radiation-induced Single Event Upsets (SEUs). Compared with the well-known SEU mitigation solution - Triple Modular Redundancy (TMR) with configuration memory scrubbing - TMR with module-based error recovery (MER) is notably more energy efficient and responsive in repairing soft-errors in the system. Unfortunately, TMR-MER systems also need to resort to scrubbing when errors occur in sub-components, such as nets, which are not recovered by MER. This paper addresses this problem by proposing a fine-grained module-based error recovery technique that without additional system hardware can localize and correct errors that classic MER fails to do. We evaluate our proposal via a fault-injection campaign on a Xilinx Artix-7 application circuit and compare the reliability, the error correction latency and the energy cost of repairing errors, of our proposal with those of a conventional MER approach and with periodic and on-demand blind scrubbing. We find the reliability of our proposal to be the highest and the energy expenditure to be the lowest amongst those methods considered.