Shared Test Channels for Non-Identical Circuit Blocks
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Solution Overview
Problem
The limited number of input/output channels for test stimuli and test response data in circuit testing creates a bottleneck when dealing with non-identical circuit blocks, leading to insufficient encoding capacity and reduced effective compression ratios.
Innovation Solution
The method involves generating compressed test patterns and control data for non-identical circuit blocks, using shared test data-only input channels for pattern shifting and separate control data input channels, with decompressors configured to handle the patterns and compactors to manage response data, allowing for efficient channel sharing among circuit blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated test channels are allocated to each circuit block, then testing reliability is improved, but device complexity and channel count increase
Solution Approach 1:
Multiple circuit blocks share common test channels through time-division multiplexing. The patent combines test resources by allowing different circuit blocks to use the same input/output channels at different time slots, thereby reducing the total number of channels required while maintaining testing reliability through coordinated access control.
Solution Approach 2:
The test channel allocation is made dynamic through time-division multiplexing. Channels are dynamically assigned to different circuit blocks based on testing schedules, allowing the system to adapt channel usage to actual testing needs rather than maintaining static dedicated allocations, thus reducing overall channel complexity.
2Productivity
If time-division multiplexing is used for channel sharing, then channel utilization is improved, but test application time increases
Solution Approach 1:
The patent implements periodic time-division multiplexing where test channels are systematically allocated to different circuit blocks in repeating time cycles. This periodic structure allows for efficient channel utilization by ensuring each block gets regular access to shared resources, while the cyclic nature enables predictable scheduling that can optimize overall test application time.
3Reliability
If compression logic is embedded in each core, then testing independence is improved, but device complexity and routing overhead increase
Solution Approach 1:
The patent merges compression functionality into shared test channels rather than embedding separate compression logic in each core. By consolidating compression resources at the channel level, the system maintains testing independence through proper channel allocation while significantly reducing routing overhead and device complexity associated with multiple distributed compression units.
Data Source
AI summary
Various aspects of the disclosed techniques relate to channel sharing techniques for testing circuits having non-identical cores. Compressed test patterns for a plurality of circuit blocks are generated for channel sharing. Each of the plurality of circuit blocks comprises a decompressor configured to decompress the compressed test patterns. Test data input channels are thus shared by the decompressors. Control data input channels are usually not shared by non-identical circuit blocks in the plurality of circuit blocks.