IRJET- Implementation of TPG-LFSR with Reseeding Pattern Value

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 06 Issue: 12 | Dec 2019 www.irjet.net p-ISSN: 2395-0072
© 2019, IRJET | Impact Factor value: 7.34 | ISO 9001:2008 Certified Journal | Page 2037
Implementation of TPG-LFSR with Reseeding Pattern Value
V. Hitesh1,YV. Narayana2, S. Rama SubbaReddy3, C. Venkateswarlu4,M. Pavan kumar5,
Venna Ramasubbareddy6
1,2,3,4,5Department of Electronics & Communication Engineering, Krishna Chaitanya Educational Institute,
Markapur, AP, INDIA
6Corresponding Author: Asst. Prof Venna Ramasubbareddy M.tech
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ABSTRACT:- In this paper we discuss about Reseeding
LFSR based test pattern generation. Traditional testing is
not a acceptable quality with the development of
integrated circuits and thickness. Testing causes the
designer to explore shortcomings and blunder present in
created circuit which diminishes time require to test and
accordingly diminishes odds of getting fizzled during
activity. Reducing the test time of the test pattern
generation is one of the most effected solution for the
process. Reseeding L_F_S_R is one of the technique to
generate test patterns. In this paper, pseudo-random test
patterns are generated to test
circuit exploitation R_L_F_S_R technique. It helps to scale
back the take a look at pattern needed to be hold on for
testing. this method is applied by exploitation principals
low-power VLSI and low take a look at
information volume. Reseeding will primarily be applied
for B_I_S_T that targets complete fault coverage and step-
down of the take a look at length information .
INTRODUCTION:
Very Large-Scale Integration created a major impact on
IC technology it is mainly used to reduce size and cost
but increases in complexity. Also it results the
performance and cost of the circuits which became boom
to the Integrated Circuits industries. Testing of circuits
became difficult as the scale of integration is increasing.
Normal testing approach is not sufficient with the
increase in growth of devices and limited area. In this
Traditional testing involves Automatic Testing
Equipment becoming more non-suitable due to the
growth of Integrated Circuits technology. Linear
Feedback Shift Registers are commonly used as pseudo-
random test pattern generators in B_I_S_T process, it is a
technique that can be used to test itself which has as an
effective approach for testing. For absolute checking of
errors in test pattern Built-In-Self Test technique gives
an optimized response some of the components of BIST
are test pattern generation and circuit under test
Response In this we mainly use T-P-G for generation of
test pattern.
• Reseeding LFSR :
Linear feedback shift registers are used to generate
pseudo-random test pattern in B_I_S_T schemes. Their
structure is simple, they require very small area
overhead and it can used for test pattern and response
generation. Some of the applications of L_F_S_R are,
counters, pseudo random pattern generation, pseudo
random sequences resistant faults. In this we use one xor
gate
Fig1: Architecture of Test pattern
For any testing methodology, some of the factors has to
be considered such as high and easy fault verifiable,
speed testing, short testing time. When there is number
of circuits in chip then it becomes complex. Then we
have to test the chip design with increasing circuit
complexity, it becomes difficult to test the chip
externally. Thus we use B_I_S_T technique provides a
multiple solution to above demands. Another advantage
of this methodology is that the test patterns are cannot
be applied by external A_T_E.
Fig2: ANDgate

Fig3: Pseudo random pattern generation 8-bit
Maximum length of seed worth given by formula 2n-
1, think about AND gate that has n input lines in
fig2.The likelihood of obtaining bit one at the output of
the AND gate is zero once unbiased random
inputs are applied. It becomes not possible to work
out the stuck at zero fault if zero applied at
input face. It’s inconceivable to acknowledge the stuck at
zero faults gift within the circuit. So, it's troublesome to
discover such form of fault from that take a look at
pattern generated. Such a Fig. 3. The implemented
design can able to generate the test patterns according to
the seed value given to the reseeding LFSR. For N bit
number the code can generate the test pattern according
to the formula 2n-1. shows the given input values are
accountable for the output generation result that is given
to the reseeding LFSR.
L_F_S_R can accomplish high flaw inclusion by
decreasing connection between the test vectors.
Reseeding is an amazing technique for diminishing the
test information volume and capacity, Size of the test
information can be diminished by L_F_S_R clock which is
inert for a few clock cycles after the information seed is
given.
• PROPOSED BLOCK DIAGARAM FOR TEST
PATTERN GENERATION
Counter is used in the system to produce the seed value.
The seed value generated should be stable for 2n-1
clock cycle. In this the circuit can be worked up to 256
(8) bits. It can accept the input value up to 256bits.
Fig-4: proposed model
Counter one price is given to the reseeding LFSR as a
seed price to n bit reseeding LFSR to get Pseudo Random
check Patterns for the actual seed value, During this the
This check patterns won't be used for testing the CUT,
since it's a lock state. LFSR is especially accustomed
enhance the fault detectability and shorten the testing
method. The reseeding LFSR comprises primitive
polynomial which will facilitate to get all the doable
combination with relevancy seed price. The seed price
that is given to LFSR is taken from the counter one. in
line with the given seed price check patterns area unit
generated. The received check patterns area unit given
to Circuit beneath check for testing the planning. Counter
is employed within the system to supply the seed value.
The seed worth generated ought to be stable for 2n-1
clock cycle. within the projected system the circuit will
exercise to bits [8]. The system will settle for the input
worth up to 256 bits. This take a look at patterns won't
be used for testing the CUT, since it's a lock state. The
reseeding LFSR include primitive polynomial which will
facilitate to get all the attainable combination with
reference to seed worth. The seed worth that is given to
LFSR is taken from the counter one. consistent with the
given seed worth take a look at patterns are generated.
That take a look at patterns are given to chop for testing
the planning.
• Experimental result :
From the implementation of Reseeding LFSR Test
pattern generation we can reduce fault circuit
occurrence, increase the efficiency by using this method.
In this BIST technique we use TPG by following
operation we can generate the result as schematic form.
Fig-5: combinational circuit output

We use counters in this technique, it is used to count the
number of cycles to perform the task, In R-LFSR we use
one XOR gate to give the inputs and in normal LFSR we
use number of XOR gates, in order to reduce complexity
we introduce RLFSR technique. We perform write (wr),
read (rd) operations and inputs are given, according to
inputs, wave forms will change and there is occurrence
of shifting operation with one clock pulse delay.
Fig-6: Reseeding LFSR
The architecture shown in Fig. 4 can be used to test the
built-in circuits to reduce the storage and time to
generate the test patterns.
Counter used to produce the automatic generation of
seed continuously which are feed to reseeding L-F-S-R
to generate required pseudo-random pattern called as
test pattern which will be provided to CUT. Test patterns
are generated through reseeding LFSR and are given to
CUT. The schematic diagram of the proposed system is
shown in Fig6. The proposed method is completed using
verilog code.
• Conclusion and future scope :
Reseeding has been planned as an efficient technique for
testing circuits with random-pattern resistant faults,
since it are able to do complete fault coverage with an
appropriate range of check vectors. During this paper a
brand new reseeding technique for L_F_S_R based check
pattern generation, appropriate for test-per-clock
B_I_S_T schemes, was planned. The generation of the
seeds is performed on- the-fly by the inversion of the
logic values of a number of the bits of the L_F_S_R next
state. This paper represents a way to come up with check
pattern appropriate for circuits with Random Pattern
Resistant Fault The technique may be enlarged to satisfy
the necessity for low power, low time demand and low
volume of check knowledge. Reseeding will primarily be
applied for BIST that targets minimization of the check
length and complete fault coverage. knowledge time
compression for the check pattern needed for testing can
indirectly scale back the overall time needed to examine
the circuits. On chip testing system may be designed for
higher space coverage and reduced memory usage.by
using cut back method we can get the fault-free circuit
with 100% accuracy.
References
[1]N. Devika, K. Bhakthavatchal, Ramesh (2017). “Design
of recon-figurable LFSR for VLSI IC testing in ASIC and
FPGA.” 0928-0932. 10.1109/ICCSP.2017.8286506.
[2] S. Sooraj and R. Bhakthavatchalu, “Hamming 3
algorithm for improving the reliability of SRAM based
FPGAs,” 2017 International Conference on
Communication and Signal Processing (ICCSP), Chennai,
2017.
[3] Zaid Ali Salman, “Design and Implementation a PC
Based System for Circuit Testing”, B.SC. Electronics
Communication Engineering 2002.
[4] M. Abramovici, M. A. Breuer, and A. D. Friedman,
Digital Systems Testing and Testable Design, Computer
Science Press, New York, NY, 1990.
[5] P. H. Bardell, W. H. McAnney and J. Savir, Built-In
Test for VLSI: Pseudo-Random Techniques, Johh Wiley &
Sons, New York, NY, 1987.
[6] V. Agrawal, Ch. Kime and K. Saluja, “A tutorial on B-I-
S-T Part 1: Principles “IEEE Design & Test of Computers,
March 1993, pp. 73-82.

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IRJET- Implementation of TPG-LFSR with Reseeding Pattern Value