Fault tolerant FPGA processor based on runtime reconfigurable modules

The increasing use of field programmable devices for the implementation of embedded processors and systems-on-chip even in mission-critical applications demands for fault tolerant techniques to improve reliability and extend system lifetime. Furthermore, the runtime partial reconfiguration potentials of the latest FPGA devices along with the availability of unused programmable resources in most FPGA designs provide interesting opportunities to build fault tolerant mechanisms. In this paper, we exploit the latest dynamic reconfiguration advances and propose a fault-tolerant FPGA processor architecture based on runtime reconfigurable modules. We partition the processor core into reconfigurable modules and duplicate these modules to implement a concurrent error detection mechanism. For every duplicated module we generate precompiled configurations which include spare resources and are used to runtime repair the defective module. The processor freezes upon the detection of an error and an on-chip controller coordinates the processor recovery and repair in a reconfiguration process transparent to the processor. We demonstrate the proposed approach in OpenRISC core, a widely-used open-source soft processor.