New FPGA blind scrubbing technique

The, well known, blind scrubbing technique used in FPGA allows continuous and fast recovery of single event upsets that may appear due to space environmental effects. The required rate of scrubbing depends on the expected occurrence of single event upsets, which varies according to both space environment parameters in orbit and shielding used on board. Blind scrubbing techniques usually do not check the occurrence of an error that interrupts the normal operation of the chip; instead, it blindly overwrites the existing configuration bits with a pre-specified rate. Scrubbing controller should be very reliable and should not be interrupted in any case; else, its operation may be defected (even with one bit) causing dramatically unexpected behavior of the FPGA. Scrubbing controller uses a pre-stored configuration bit (sometimes-called golden stream) to overwrite the configuration stream. This methodology is one of the most effective fault tolerant techniques used on board satellites; however, the method implies usage of more reliable processing and storage components with less failure rate. In this paper, we introduce a new architecture for implementing blind scrubbing using commercial components. The proposed technique depends on magneto-resistive memory for storage of configuration stream the need for scrubbing controller is omitted and we only used this scheme (FPGA configuration based on MRAM) as an independent solution to avoid system complexity. Magneto-resistive memory is a newly developed technology that has been as a reliable storage platform with excellent performance in radiation environment. Results showed that the proposed technique is reliable and ready to be tested in radiation facility; it seems also that it may have promising applications since it enables low cost solutions and simple utilization of commercially available components with independence of needed critical controller.