The document discusses design for testability (DFT) techniques. It explains that DFT is important for testing integrated circuits due to unavoidable manufacturing defects. DFT aims to increase testability by making internal nodes more controllable and observable. Common DFT techniques mentioned include adding scan chains, which allow testing at speed by launching test vectors from a shift register. Stuck-at fault and transition fault models are discussed as well as methods for detecting these faults including launch-on-capture and launch-on-shift. Fault equivalence and collapsing techniques are also summarized.
Scan design is currently the most popular structured DFT approach. It is implemented by Connecting selected storage elements present in the design into multiple shift registers, called Scan chains.
Scannability Rules -->
The tool perform basic two check
1) It ensures all the defined clocks including set/Reset are at their off-states, the sequential element remain stable and inactive. (S1)
2) It ensures for each defined clocks can capture data when all other defined clocks are off. (S2)
Level sensitive scan design(LSSD) and Boundry scan(BS)Praveen Kumar
This presentation contains,
Introduction,design for testability, scan chain, operation, scan structure, test vectors, Boundry scan, test logic, operation, BS cell, states of TAP controller, Boundry scan instructions.
Spyglass DFT is comprehensive process of resolving RTL Design issues, thereby ensuring high quality RTL with fewer design bugs.
Improves test quality by diagnosing DFT issues early at RTL or netlist.
Shortens test implementation time and cost by ensuring RTL or netlist is scan-compliant.
Scan design is currently the most popular structured DFT approach. It is implemented by Connecting selected storage elements present in the design into multiple shift registers, called Scan chains.
Scannability Rules -->
The tool perform basic two check
1) It ensures all the defined clocks including set/Reset are at their off-states, the sequential element remain stable and inactive. (S1)
2) It ensures for each defined clocks can capture data when all other defined clocks are off. (S2)
Level sensitive scan design(LSSD) and Boundry scan(BS)Praveen Kumar
This presentation contains,
Introduction,design for testability, scan chain, operation, scan structure, test vectors, Boundry scan, test logic, operation, BS cell, states of TAP controller, Boundry scan instructions.
Spyglass DFT is comprehensive process of resolving RTL Design issues, thereby ensuring high quality RTL with fewer design bugs.
Improves test quality by diagnosing DFT issues early at RTL or netlist.
Shortens test implementation time and cost by ensuring RTL or netlist is scan-compliant.
01 Transition Fault Detection methods by Swethaswethamg18
Fault Models
Stuck-at fault test covers
Shorts and opens
Resistive shorts – Not covered
Delay fault test covers
Resistive opens and coupling faults
Resistive power supply lines
Process variations
Delay Fault Testing
Propagation delay of all paths in a circuit must be less than clock period for correct operation
Functional tests applied at operational speed of circuit are often used for delay faults
Scan based stuck-at tests are often applied at speed
However, functional and stuck-at testing even if done at-speed do not specifically target delay faults
A VLSI (Very Large Scale Integration) system integrates millions of “electronic components” in a small area (few mm2 few cm2).
design “efficient” VLSI systems that has:
Circuit Speed ( high )
Power consumption ( low )
Design Area ( low )
Introduction of testing and verification of vlsi designUsha Mehta
This slides are introductory slides for the course testing and verification of VLSI Design which cover the basics of Why, Where, When and How of VLSI design testing
01 Transition Fault Detection methods by Swethaswethamg18
Fault Models
Stuck-at fault test covers
Shorts and opens
Resistive shorts – Not covered
Delay fault test covers
Resistive opens and coupling faults
Resistive power supply lines
Process variations
Delay Fault Testing
Propagation delay of all paths in a circuit must be less than clock period for correct operation
Functional tests applied at operational speed of circuit are often used for delay faults
Scan based stuck-at tests are often applied at speed
However, functional and stuck-at testing even if done at-speed do not specifically target delay faults
A VLSI (Very Large Scale Integration) system integrates millions of “electronic components” in a small area (few mm2 few cm2).
design “efficient” VLSI systems that has:
Circuit Speed ( high )
Power consumption ( low )
Design Area ( low )
Introduction of testing and verification of vlsi designUsha Mehta
This slides are introductory slides for the course testing and verification of VLSI Design which cover the basics of Why, Where, When and How of VLSI design testing
Wavelet Based on the Finding of Hard and Soft Faults in Analog and Digital Si...ijcisjournal
In this paper methods for testing both software and hardware faults are implemented in analog and digital
signal circuits are presented. They are based on the wavelet transform (WT). The limit which affected by
faults detect ability, for the reference circuits is set by statistical processing data obtained from a set of
faults free circuits .In wavelet analysis it has two algorithm one is based on a discrimination factor using
Euclidean distances and the other mahalanobis distances, are introduced both methods on wavelet energy
calculation. Simulation result from proposed test methods in the testing known analog and digital signal
circuit benchmark are given. The results shows that effectiveness of existing methods two test metrics
against three other test methods, namely a test method based on rms value of the measured signal, a test
method utilizing the harmonic magnitude component of the measured signal waveform
Vlsi Design of Low Transition Low Power Test Pattern Generator Using Fault Co...iosrjce
Now a day’s highly integrated multi layer board with IC’s is virtually impossible to be accessed
physically for testing. The major problem detected during testing a circuit includes test generation and gate to
I/O pin problems. In design of any circuit, consuming low power and less hardware utilization is an important
design parameter. Therefore reliable testing methods are introduced which reduces the cost of the hardware
required and also power consumed by the device. In this project a new fault coverage test pattern generator is
generated using a linear feedback shift register called FC-LFSR which can perform fault analysis and reduces
the total power of the circuit. In this test, it generates three intermediate patterns between the random patterns
which reduces the transitional activities of primary inputs so that the switching activities inside the circuit under
test will be reduced. The test patterns generated are applied to c17 benchmark circuit, whose results with fault
coverage of the circuit being tested. The simulation for this design is performed using Xilinx ISE software using
Verilog hardware description language
Enhanced Skewed Load and Broadside Power Reduction in Transition Fault TestingIJERA Editor
This Paper Proposes the T-algorithm technique to optimize the testing Skewed Load and Broadside architecture. And the architecture used to the compare the test pattern results. In this architecture, T-algorithm used to optimize the testing architecture. This architecture compare the test pattern output for the required any type of combinational architecture. The optimization process mainly focused by gate optimization for secure architecture. The proposed system to use the T-algorithm, to optimize the testing clocking level for the required test patterns. This technique to replace the flip flop and the mux arrangement. To reduce the flip flops in Skewed Load architecture. And to develop the accuracy for testing architecture. The proposed system consists of the secure testing architecture and includes the XOR-gate architecture. So the modification process applied by the Broadside and over all Skewed Load architecture. The proposed technique to check the scanning results for the testing process. The testing architecture mainly used to the error attack for the scanning process and the scanning process work with any type of testing architecture. The scanning process to be secure using the T-algorithm for the Skewed Load architecture. And to develop the testing process for the fault identification process. The diagnosis technique to detect error for the scanning process in any type combinational architecture. The T-algorithm used to reduce the circuit complexity for the testing architecture and the testing architecture used to reduce the delay level. And the future process, this technique used to reduce the gate level for the sticky comparator architecture and to modify the clocking function for the testing process. This technique to develop the accuracy level for the testing process compare to the present methodology.
Design for Testability in Timely Testing of Vlsi CircuitsIJERA Editor
Even though a circuit is designed error-free, manufactured circuits may not function correctly. Since the manufacturing process is not perfect, some defects such as short-circuits, open-circuits, open interconnections, pin shorts, etc., may be introduced. Points out that the cost of detecting a faulty component increases ten times at each step between prepackage component test and system warranty repair. It is important to identify a faulty component as early in the manufacturing process as possible. Therefore, testing has become a very important aspect of any VLSI manufacturing system.Two main issues related to test and security domain are scan-based attacks and misuse of JTAG interface. Design for testability presents effective and timely testing of VLSI circuits. The project is to test the circuits after design and then reduce the area, power, delay and security of misuse. BIST architecture is used to test the circuits effectively compared to scan based testing. In built-in self-test (BIST), on-chip circuitry is added to generate test vectors or analyze output responses or both. BIST is usually performed using pseudorandom pattern generators (PRPGs). Among the advantages of pseudorandom BIST are: (1) the low cost compared to testing from automatic test equipment (ATE). (2) The speed of the test, which is much faster than when it is applied from ATE. (3) The applicability of the test while the circuit is in the field, and (4) the potential for high quality of test.
Discrete-event simulation: best practices and implementation details in Pytho...Carlos Natalino da Silva
Discrete-event simulation is one of the most useful techniques to evaluate quickly and effectively the performance of systems. It enables benchmarking proposed strategies against existing ones in a time- and computing-efficient manner. However, there are several aspects that should be considered when designing and implementing your simulation environment. In this tutorial, a number of best practices when designing and implementing event-driven simulations will be discussed. A use case of routing in optical networks will be used as an example. The implementation of the main simulator components using Java and Python will be described.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
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Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
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A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
2. Agenda
Importance of Testing.
What is Testability.
What is DFT? Why?
DFT Technique.
Manufacturing Defects.
Fault Modelling.
Methods To Test Transition Fault.
Fault Equivalence / collapsing.
Structured Approach.
3. Importance of Testing
§ According to Moore’s law feature size is decreasing.
defects are unavoidable.
§ Testing is required to guarantee fault-free chips.
§ Product quality depends on the following parameters,
ü Test cost
ü Test quality
ü Test time
§ DFT – “The game changer”
4. What is Testability?
The ability to put a design into a known initial state, and then control
and observe internal signal values.
Circuit without DFFs: Circuit is controllable and observable.
Circuit with DFFs: Low testability.
Two basic properties determine the testability of a node:
Controllability
The ability to set node to a specific value.
Observability
The ability to observe a node’s value.
5. What is DFT?
DFT refers to hardware design styles, or added hardware that reduces
test generation complexity.
Philosophy of DFT is Murphy's law:- ”whatever can go wrong, will go
wrong.”
Motivation:- : Test generation complexity increases exponentially with
the size of the circuit.
Basically DFT enables the manufacturing test.
It is a structural technique, which facilitates a design to become testable
after production .
6. Why DFT
To increase Productivity:
Shorter time-to-market
Reduced design cycle
Reduced cost
To improve Quality:
Reduced Defects per million (DPM)
Improved quality of test
7. DFT Technique
Ad-hoc Technique.
Ø As name implies Ad-hoc Technique is a temporary Technique.
Ø Is a strategy to enhance the design testability without making much change
to design style.
Ø Good design practices learnt through experience are used as guidelines for
ad-hoc DFT.
Structural Technique.
Ø Here it provides more systematic & automatic approach to enhance the
design testability.
Ø Targets manufacturing defects.
8. Manufacturing Defects
Physical problem in silicon:
q Extra metal-causing shorts.
q Insufficient Doping.
q Contamination causing opens.
q CMOS Stuck-ON.
q CMOS Stuck-OPEN.
q Slow Transistors.
9. Cont...
Defect: The term defect generally refers to a physical imperfection in
the processed wafer.
Some defects are observable through the optical or electron
microscope. Others are not visible and can only be detected by
electrical tests.
Fault: A representation of a “defect” at the abstracted function level is
called a fault.
Error: A wrong output signal produced by a defective system is called
an error.
Failure: Repeated occurrence of the same defect indicates the need for
improvements in the manufacturing process or the design of the device.
Procedures for diagnosing defects and finding their causes are known
as failure mode analyses (FMA).
10. Fault Modelling
Due to defect during manufacturing of integrated circuit, There is need to
model the possible faults that might occur during fabrication process, this is
called fault modelling.
v Stuck-at-fault.
v Transition fault.
§ Stuck-at-fault: From the beginning of the DFT single stuck-at fault model is
the most popular fault model used in practice. This is mainly due to process
variations, imperfection during photolithography and etching, the metal.
B
Y
A
11. Stuck-at-fault example
§ Fault activation
§ Fault propagation
§ Line justification
i
e
D
X
g
j
f
h
D
D
a
b=1
c
d
S-a-0
Figure Sensitization by b=1, Propagation path by e-f-g-h
12. D Algorithm
Target a specific stuck-at-fault.
Drive fault site to to opposite value.
Propagate error to primary outputs.
Generate patterns for one Stuck-at-fault at a time.
Involve decision-making at almost every step.
13. Transition Fault Model
§ The transition fault is similar to the stuck-at fault in many respects.
§ The effect of a transition fault at any point P in a circuit is that a rising or a
falling transition at P will not reach an observable output such as a scan
flip-flop or a primary output within the desired time.
A
B
C
14. Methods To Test Transition Fault
Delay tests require a vector pair to detect a fault.
Since the patterns must be applied at the rated speed, at-speed
testing is needed.
For full scan circuits, both the vectors in the scan flip-flops must be
ready for consecutive time frames to ensure atspeed testing.
Several different methods are used to apply the vectors at-speed.
Transition faults are detected through scan chain. There are two
methods to detect transition faults.
Skew Load or Launch-From-Shift (LOC).
Skew Load or Launch-From-Shift (LOS).
16. Fault Equivalence / collapsing
The gates behaves the same for any input
SA0 ,SA1 or the output SA0 ,SA1 .
The fault after collapsing are included in the
fault universe called primary faults, the faults
after collapsing are not included in the fault
universe are called Equivalent fault of primary
faults.
Fault Coverage = # of Detectable faults
Total no of faults
Test Coverage = # of Detectable faults
# of Detected faults.
17. Structured Approach
The structured DFT approach tries to boost the overall testability of a
circuit with a test oriented style methodology.
This approach is organized and systematic with far more inevitable results.
Scan style, the most widely used structured DFT methodology, tries to
boost testability of a circuit by rising the controllability and observability of
storage elements in an exceedingly sequential style.
Typically, this is often accomplished by converting the sequential design
into a scan design with 3 modes of operation they are,
normal mode.
shift mode.
capture mode.
Circuit operations with associated clock cycles conducted in these 3 modes
are referred to as normal operation, shift operation, and capture operation,
respectively.
18. Scan Cell Designs
There are three types of scan cell designs, they are:
Muxed-D scan cell.
Clocked scan cell.
LSSD scan cell.
Muxed-D Scan cell:
19. Need for Scan Design
The need for Scan design in a sequential design can be well understood by
considering a example shown in Figure below.
20. Cont...
These scan chains are made externally accessible by connecting the scan
input of the first scan cell in a scan chain to a primary input and the output
of the last scan cell in a Scan chain to a primary output.
•
Scan design is currently the most popular structured DFT approach. It is
implemented by Connecting selected storage elements present in the
design into multiple shift registers, called Scan chains