What is abort points in LEC?

What is abort points in LEC?

A common issue that all LEC users must face is Abort points, cases where the tool is unable to complete verification of some points due to lack of computing power.

What is equivalence check in VLSI?

Definition. Equivalence checking is a portion of a larger discipline called formal verification. This technology uses mathematical modeling techniques to prove that two representations of design exhibit the same behavior.

How do you run conformal?

Learning Objectives

1. Use Conformal logic equivalence checking for flat and hierarchical design comparison.
2. Read libraries and designs.
3. Apply design constraints and modeling directives.
4. Apply the mapping process and debug unmapped key points.
5. Apply the compare process and debug non-equivalent points.

How do you run LEC?

Run the below commands on terminal in order to run the program file.

1. Step 1: lex filename.l or lex filename.lex depending on the extension file is saved with.
2. Step 2: gcc lex.yy.c.
3. Step 3: ./a.out.
4. Step 4: Provide the input to program in case it is required.

What is the difference between LVS and LEC in VLSI?

LEC and LVS are checks used in different stages of physical design to ascertain the functionality and layout sanity respectively. Both are done at different phases of the PNR flow. LEC starts as early as the front end and goes on till the final tape-out phase whereas LVS is primarily a backend sanity check.

What is FEV in VLSI?

Introduction to Formal Equivalence Verification (FEV)

What is LEC check in VLSI?

A logic synthesis tool guarantees that the netlist is logically equivalent to the RTL source code. LEC (Logic Equivalence Check) is the essential step to ensure the functional check between RTL and netlist as can also be depicted from the Fig. 1. Many EDA companies provide tools to do the check.

What is unmapped logic?

Unreachable unmapped points are key points that do not have an observable point, such as a primary output. Not-mapped unmapped points are key points that are reachable but do not have a corresponding point in the logic fan-in cone of the corresponding design.

What is conformal in VLSI?

Conformal technology combines low-power equivalence checking with structural and functional checks to enable full-chip verification of power-efficient designs. These advanced low-power design methods can also complicate the verification task, introducing risk during synthesis and physical implementation.

Why do people do LVS?

open, shorts, missing components, and missing global net connect are potential issues that can affect the functionality of design and may not be detected at early implementation stage, so LVS is useful to report these issues in design.

What is functional equivalence?

Functionally equivalent means when a practice, method, technique, procedure, design, material, or component performs the same function and provides the same or improved utility as is being required through the rule.

What is logic cone in VLSI?

A logical cone is a window that displays only a portion of a netlist. You can add individual instances, blocks, and ports to a logical cone. You can also remove objects from this cone. Logical cones help you navigate and analyze a specific part of the design.

What are not-mapped unmapped points?

Not-mapped unmapped points are key points that are reachable but do not have a corresponding point in the logic fan-in cone of the corresponding design. After the Conformal tool maps the key points, the next step of the verification is comparison.

How to execute the conformal tool using LEC?

For the execution of LEC, the Conformal tool requires three types of files. .lec file guide the Conformal tool to execute different command in a systematic way. .scan_const file provides scan related constraints like if we want to ignore some scan connections/serdes input/output pins which are defined in this file.

How do I map key points in the conformal tool?

The Conformal tool employs two name-based methods and one no-name method to map key points. Name-based mapping is useful for gate-to-gate comparisons when minor changes have been made to the logic. Conversely, the no-name-mapping method is useful when the Conformal tool must map designs with completely different names.

What is the main check with LEC?

Normally the main check with LEC is to find non-equivalent points. Why are you interested in not-mapped points? Said. Whenever I debug the Not Equivalent Point, I come across the Non-Mapped Point as a Non Corresponding Support. So I am assuming that this is the cause of the failure. what kind of EqCheck are you doing : g2g or r2g?