Configurable Decompression Circuitry for Scan Chain Interoperability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The integration of circuit blocks with scan chains into larger systems is constrained by proprietary compression and decompression schemes from specific EDA vendors, limiting interoperability and flexibility, as existing standards like the Open Compression Interface do not provide a truly vendor-neutral solution.
Innovation Solution
A data processing apparatus with configurable decompression and compression circuitry that supports multiple decompression and compression schemes, allowing selection and configuration of schemes via a configuration stimulus, enabling the use of test data from various EDA tools and providing flexibility in chip design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If proprietary decompression and compression schemes from specific EDA vendors are used, then test data can be processed through scan chains, but interoperability and flexibility are limited when integrating into larger systems
Solution Approach 1:
The decompression circuit is designed to support multiple decompression schemes (first and second schemes) within a single circuit block. The configuration circuit enables the same hardware to be adaptively configured to match different EDA vendor schemes, making the circuit universal and compatible with various test data sources without requiring separate dedicated circuits for each vendor
Solution Approach 2:
The decompression circuit transitions from a static, vendor-specific design to a dynamic, reconfigurable system. The configuration circuit receives a configuration stimulus and dynamically adjusts the decompression circuit's behavior to match the required scheme, enabling adaptability while maintaining a single hardware implementation
2Adaptability or versatility
If a single EDA vendor's scan compression scheme is used throughout a chip, then integration consistency is maintained, but flexibility to use different EDA tools is lost
Solution Approach 1:
The system dynamically adapts its decompression behavior based on the configuration stimulus that identifies which EDA vendor scheme is being used. This allows different circuit blocks on the same chip to be configured for different vendors while maintaining internal consistency within each block, resolving the conflict between flexibility and reliability
3Quantity of substance
If compressed input test data is received through a limited number of scan-in pins, then pin count is reduced, but decompression logic becomes EDA tool dependent
Solution Approach 1:
The decompression circuit is designed as a universal solution that can handle compressed data from multiple EDA vendors through the same scan-in pins. The configuration circuit enables the hardware to adapt to different compression formats, maintaining pin efficiency while achieving vendor neutrality
Data Source
AI summary
A data processing apparatus comprises a circuit block to be tested, and a plurality of scan chains, each scan chain providing a mechanism for providing input test data to, and receiving output test data from, at least a portion of the circuit block during a test mode of operation. Configurable decompression circuitry is provided for supporting a plurality of decompression schemes associated with more than one test generation tool, and configuration circuitry is responsive to a configuration stimulus to configure the configurable decompression circuitry to implement a selected decompression scheme. Thereafter, on receipt of compressed input test data, the configurable decompression circuitry applies the selected decompression scheme to the compressed input test data to produce the input test data to be provided to the plurality of scan chains. Configurable compression circuitry can also be provided in a similar manner, with the configuration stimulus being used to configure the configurable compression circuitry to implement a selected compression scheme to be applied to the output test data in order to produce compressed output test data to be issued from an output interface. Such a mechanism provides a particularly flexible approach for supporting compression and decompression schemes in association with the data input to, and output from, the plurality of scan chains.