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This paper evaluates the area and performance overhead of a programmable cryptographic accelerator specialized to sup-port ARX (Add, Rotate, and Xor) based encryption stan-dards, which are common in symmetric cryptography. This overhead is measured by comparing to a variety of custom ARX

to the resulting circuits their considerable overhead due to the implementation of handshaking protocols. In our proposed method, the overhead is reduced 50 % by separating the control and data path units. This solution increases the forks, and causes complexity in physical implementation. By applying some

The concept of Random Access Scan (RAS) where every Flip-Flop is addressed uniquely has been subject to criticism at the very thought. It seems at the first impulse that the cost associated with routing is overwhelming. This argument has shelved the idea for 25 years now. In this paper we propose an architecture that minimizes the signals to the RAS Flip-Flop (FF) and give an estimate of the increase in area due to the increase in gates and increase in routing. Two global signals, scanin and mode control, have been eliminated from the previous RAS designs presented in the literature. For n flip-flops, instead of routing n address wires, one to each FF, we use √ n wires in an xy matrix layout. A unique toggle mechanism is incorporated in the RAS FF that totally eliminates the scanin signal wire and reduces the vector set up to 60 % compared to traditional serial scan (SS). The SS induces unnecessary circuit activity during scan and the circuit under test (CUT) dissipates an enormous amount of power. Our design reduces the power dissipation by 99%. The problem of delay testing is highly constrained in SS and the scan-cell is often modified to assist delay testing. Any single input change delay test can be directly applied in our design. Hence all testable paths in the circuit can be effectly tested without constraints. We also propose a multistage scanout system to observe the addressed FF avoiding a slow output bus with very high capacitance. 1

, this scheme can be efficiently utilized to drive down the hardware of BIST pattern generation, as well. Comparisons with previously presented schemes indicate that the proposed scheme compares favorably with respect to the required hardware. Index Terms: BIST, test per clock, VLSI testing, weighted test

and providing more information per memory access. For the Leon processor and a set of benchmarks from the Mediabench and MiBench suites the habitual overheads due to security trend to zero in comparison to a system without security neither compression.

This paper describes a methodology of creating a built-in diagnostic system of a System on Chip and experimental results of the system application on the AT94K FPSLIC with cores designed according to the IEEE 1500 standard. The system spares memory and keeps acceptable test access mechanism requirements. The diagnostic system uses a built-in processor for test control, the embedded RAM memory for storing both the compressed test vectors and the partial reconfiguration bit streams and the FPGA (Fieldprogrammable gate array) part of the chip for the wrapped cores implementation. The highly compressed test vectors are transferred from the memory to those selected cores that are reconfigured into the embedded tester cores. The patterns are decompressed within the internal scan chains of the embedded tester cores and they are simultaneously fed into the parallel scan chains of the cores under test through Test Access Mechanism (TAM) and standard wrappers. After having tested the first cores under test the TAM of the System on Chip (SoC) is partially reconfigured with the help of the partial reconfiguration bitstreams stored in the RAM memory and the till now untested cores are tested by those cores that start to serve as embedded testers. By this traveling reconfiguration and testing the whole circuit can be tested. For test data compression we use a test pattern compaction and compression algorithm called COMPAS. It reorders and compresses test patterns previously generated in an Automatic Test Pattern Generation (ATPG) in such a way that they are well suited for decompression by the scan chains in the embedded tester cores. The algorithm compresses the test patterns by overlapping patterns originally generated by an ATPG. The volume of test data stored in the embedded RAM is

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due to the fast switching scan enable signal, the hybrid delay scan does not require a strong buffer or buffer tree to drive the fast switching scan enable signal. Hardware overhead added to standard scan designs to implement the hybrid approach is negligible. Since the fast scan enable signal

communication costs. Research prototypes of message driven machines demonstrate low communication overhead, but poor processor cost/performance. We introduce a simple communication mechanism, Active Messages, show that it is intrinsic to both architectures, allows cost effective use of the hardware, and offers