Circuit Verification Using Observation Points for Code Coverage
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Solution Overview
Problem
The increasing complexity of LSI circuits and the need for reduced design time lead to verification misses, as existing methods rely on code coverage indices that are impractical for actual tests, lacking objective standards for test coverage properties.
Innovation Solution
A circuit verifying apparatus and method that measures code coverage by extracting signals from observation points within the logic circuit, using a coverage observing unit to determine executed code ratios, and a coverage collecting unit to quantify and output these ratios, enabling objective test coverage evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If code coverage measurement is performed using existing methods, then verification accuracy is improved, but the method becomes impractical for actual tests due to lack of objective standards
Solution Approach 1:
The patent introduces an intermediary mechanism (coverage observing unit and coverage collecting unit) that bridges the gap between simulation test coverage measurement and actual test coverage measurement. This intermediary system enables objective code coverage measurement in actual tests by inserting observation points in the logic circuit and collecting execution information, thus making coverage measurement practical and standardized for actual testing scenarios.
2Adaptability or versatility
If LSI circuit complexity increases, then circuit functionality is improved, but verification miss rate increases
Solution Approach 1:
The patent applies segmentation by dividing the complex LSI circuit into multiple segments with observation points inserted at strategic locations. The coverage observing units are distributed throughout the circuit, each monitoring a specific segment. This segmentation approach makes verification of complex circuits manageable by breaking down the overall verification task into smaller, monitorable units, thereby maintaining verification accuracy despite increasing circuit complexity.
3Productivity
If design time is reduced, then productivity is improved, but verification coverage may be insufficient
Solution Approach 1:
The patent implements preliminary action by pre-inserting observation points and coverage observing units into the logic circuit during the design phase. This preparation is done before actual testing, so that when tests are executed, coverage measurement is already in place and can immediately provide objective feedback. This eliminates the need for time-consuming setup during testing, thus maintaining fast design cycles while ensuring comprehensive verification coverage.
Data Source
AI summary
A circuit verifying apparatus, which calculates code coverage of a measurement-target logic circuit written in a hardware description language, including: a coverage observing unit which measures whether a code corresponding to a measurement-target signal extracted from each of plural observation points, which are arranged inside the measurement-target logic circuit, is carried out or not; and a coverage collecting unit which collects measurement results acquired by the coverage observing unit, and measures quantitatively a ratio of tested codes to whole codes which describe the measurement-target logic circuit, and outputs the ratio.