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Fault Injection (FI) is the most popular technique used in the evaluation of fault effects and the dependability of a design. Fault Simulation/Emulation (S/E) is involved in several applications such as test data generation, test set evaluation, circuit testability, fault detection & diagnosis, and many others. These applications require a faulty module of the original design for fault injection testing. Currently, Hardware Description Languages (HDL) are involved in improving methodologies related to the digital system testing for Field Programmable Gate Array (FPGA). Designers can perform advanced testing and fault S/E methods directly on HDL. To modify the HDL design, it is very cumbersome and time-consuming task. Therefore, a fault injection tool (RASP-FIT) is developed and presented, which consists of code-modifier, fault injection control unit and result analyser. However, in this paper, code modification techniques of RASP-FIT are explained for the Verilog code at different abstraction levels. By code-modification, it means that a faulty module of the original design is generated which includes different permanent and transient faults at every possible location. The RASP-FIT tool is an automatic and fast tool which does not require much user intervention. To validate these claims, various faulty modules for different benchmark designs are generated and presented.

Triple Modular Redundancy (TMR) technique is one of the most well-known techniques for error masking and Single Event Effects (SEE) protection for the FPGA designs. These FPGA designs are mostly expressed in hardware description languages, such as Verilog and VHDL. The TMR technique involves triplication of the design module and adding the majority voter circuit for each output port. Building this triplication scheme is a non-trivial task and requires a lot of time and effort to alter the code of the design. In this paper, the RASP-TMR tool is developed and presented that has functionalities to take a synthesizable Verilog design file as an input, parse the design and triplicate it. The tool also generates a top-level module in which all three modules are instantiated and finally adds the proposed majority voter circuit. This tool, with its graphical user interface, is implemented in MATLAB. The tool is simple, fast and user-friendly. The tool generates the synthesizable design that facilitates the user to evaluate and verify the TMR design for FPGA-based systems. A simulation scenario is created using Xilinx ISE tools and ISim simulator. Different fault models are examined during simulations such as bit-flip and stuck at 1/0. The results using various benchmark designs demonstrate that the tool produces synthesizable code and the proposed majority voter logic perfectly masks the error/failure.

Reliability and fault tolerance of FPGA systems is a major concern nowadays. The continuous increase of the system's complexity makes the reliability evaluation extremely difficult and costly. Redundancy techniques are widely used to increase the reliability of such systems. These techniques provide a large area & time overheads which cause more power consumption and delay, respectively. An experimental evaluation method is proposed to find critical nodes of the FPGA-based designs, named "hardness analysis technique" under the proposed RASP-FIT tool. After finding the critical nodes, the proposed redundant model is applied to those locations of the design and the code is modified. The modified code is functionally equivalent and is more hardened to the soft-errors. An experimental setup is developed to verify and validate the criticality of these locations found by using hardness analysis. After applying redundancy to those locations, the reliability is evaluated concerning failure rate reduction. Experimental results on ISCAS'85 combinational benchmarks show that a min-max range of failure reduction (14%-85%) is achieved compared to the circuit without redundancy under the same faulty conditions, which improves reliability.