JTAG Microcontroller Data Transfer via MEMORY_STREAM_ACCESS
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Solution Overview
Problem
The increasing complexity and density of surface mount technology and printed circuit boards require more efficient and cost-effective methods for testing, particularly for devices with high pin pitches and dual-sided ICs, where conventional contact test methods become costly and complex.
Innovation Solution
The implementation of a JTAG-based system that allows for efficient sequential block data transfer within a microcontroller system using the MEMORY_STREAM_ACCESS instruction, enabling data transfer without changing the JTAG state machine's state, thereby increasing bandwidth and reducing hardware complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional contact test methods are used for high pin pitch devices and dual-sided ICs, then testing capability is achieved, but device complexity and test fixture complexity increase significantly
Solution Approach 1:
The patent replaces mechanical contact-based testing with non-contact electromagnetic field-based testing. The test fixture uses electromagnetic fields to interact with boundary scan cells in the IC, eliminating the need for physical probes to contact pins. This substitution resolves the contradiction by maintaining testing capability while eliminating the complexity associated with mechanical contact fixtures for high pin pitch and dual-sided devices.
Solution Approach 2:
The patent introduces boundary scan cells as intermediary elements between the test fixture and the IC pins. These cells provide controlled and observed signal paths that allow testing without direct physical contact. The boundary scan architecture acts as a mediator that enables non-contact testing while maintaining full testing capability, thus reducing test fixture complexity.
2Manufacturing precision
If probe tips are made smaller to test high pin pitch devices, then testing resolution is improved, but manufacturing precision and cost increase
Solution Approach 1:
The patent replaces mechanical probe tips with electromagnetic field-based testing. Instead of manufacturing increasingly smaller physical probes to achieve higher resolution, the system uses electromagnetic fields that can be precisely controlled and directed without physical contact. This eliminates the need for expensive, precision-manufactured small probe tips while maintaining or improving testing resolution.
3Adaptability or versatility
If conventional JTAG data transfer methods are used, then protocol compatibility is maintained, but data transfer bandwidth is limited
Solution Approach 1:
The patent implements dynamic data transfer modes that can operate in both traditional byte-by-byte JTAG mode and accelerated block transfer mode. The system dynamically selects the appropriate transfer mode based on the operation requirements, allowing it to maintain protocol compatibility for standard operations while achieving high bandwidth for bulk data transfers. This dynamic approach resolves the contradiction between compatibility and productivity.
Solution Approach 2:
The patent segments data transfer into two distinct modes: traditional byte-by-byte transfer for compatibility and block transfer for high bandwidth. By dividing the data transfer function into these two segments, the system can use the appropriate mode for each operation, maintaining protocol compatibility when needed while achieving high productivity during bulk transfers.
4Productivity
If additional hardware is added to increase JTAG bandwidth, then data transfer rate is improved, but hardware complexity increases
Solution Approach 1:
The patent achieves high data transfer rates by dynamically utilizing existing JTAG hardware resources more efficiently. Instead of adding static hardware components, the system dynamically configures and controls the existing boundary scan cells and shift registers to enable accelerated block transfers. This dynamic resource utilization increases productivity without increasing hardware complexity.
Data Source
AI summary
System and methods transfer data over a microcontroller system test interface. The system can read data from and write data to microcontroller system memory using the described method. The method provides for the efficient transfer of data, minimizing redundancies and overhead present in conventional microcontroller test system protocols.