DRAM-Based Scan Data Access for Higher-Coverage In-Field Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing in-field testing of processor-based systems lacks comprehensive testing coverage due to limitations in accessing and storing large-sized test scan data, which is crucial for identifying and repairing defects effectively.
Innovation Solution
The processor-based system is configured to utilize external dynamic random access memory (DRAM) for storing and accessing test scan data, allowing the built-in testing system to perform higher coverage testing by loading test data files into DRAM during boot-up operations, bypassing the memory controller to ensure efficient and extensive testing without relying on external storage devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If in-field testing is performed using conventional memory structures, then testing can be conducted, but the testing coverage is limited due to insufficient storage capacity for large-sized test scan data
Solution Approach 1:
The patent merges the test scan data storage function with the existing DRAM system memory, combining the built-in testing system with external memory resources. This allows the testing system to utilize the large capacity of DRAM (gigabytes scale) rather than being limited to small on-chip memory, thereby enabling comprehensive testing coverage while using existing system components.
Solution Approach 2:
The DRAM system memory is designed to serve dual purposes: normal system operation and test scan data storage. By making the memory system universal, the same physical memory resources can be used for both computational tasks and comprehensive testing, eliminating the need for separate dedicated test memory and enabling high-capacity test data storage.
2Reliability
If large-sized test scan data is stored in external memory, then comprehensive testing coverage is achieved, but the complexity of data access and management increases
Solution Approach 1:
The built-in testing system automatically manages the test scan data stored in DRAM without requiring external intervention. The system self-configures to use available DRAM capacity, automatically loads test patterns, and manages test data sequences, thereby reducing operational complexity while enabling comprehensive testing coverage.
Solution Approach 2:
Test scan data is pre-loaded into DRAM during system initialization or boot-up operations before actual testing begins. This preliminary action prepares the memory with all necessary test patterns in advance, eliminating the need for complex real-time data management during testing and simplifying the test execution process.
3Productivity
If test data is loaded into DRAM during boot-up operations, then efficient testing is enabled, but the boot-up process becomes more complex
Solution Approach 1:
The test data loading function is merged with the existing boot-up sequence, combining system initialization and test preparation into a single integrated process. This eliminates the need for separate test data loading operations and leverages existing boot-up infrastructure, thereby improving testing efficiency without significantly increasing overall system complexity.
Solution Approach 2:
The patent introduces a memory controller as an intermediary that manages data transfer between external storage and DRAM during boot-up. This intermediary component handles the complexity of large data transfers automatically, enabling efficient test data loading while shielding the rest of the system from complex memory management details.
Data Source
AI summary
Processor-based system supporting in-field testing using external dynamic random access memory (DRAM) for storing and accessing test scan data. The processor-based system includes a processor that includes one or more central processing units (CPUs) that each have access to resources, such as cache memory, a memory controller to access system memory (e.g., DRAM), interfaces circuits, to perform tasks by executing of program code. The processing-based system includes an internal, built-in testing system that allows the processor-based system to be placed into test mode to perform in-field testing of the processor-based system. To support larger-sized scan data, the processor-based system is configured for the built-in-test system to access test scan data stored in DRAM in the processor-based system in a test mode. In this manner, the DRAM supports storing larger-sized test scan data so that greater in-field test coverage can be performed in the processor-based system.