External Interface Test Signal Routing for Live IC Debugging
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Solution Overview
Problem
Integrated circuits face a challenge in acquiring internal operational signals for debugging and testing without increasing the cost and size by dedicating separate test signal output paths, which conflicts with the goals of ease of debugging and cost-effective manufacturing.
Innovation Solution
A method and structure that utilize a test signal routing hierarchy to select and apply internal operational signals to an external interface during normal operation, eliminating the need for dedicated test output paths by routing these signals through existing communication channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated test signal output paths are implemented, then internal operational signals can be acquired for debugging and testing, but the cost and space occupation on the die increase
Solution Approach 1:
The patent applies multi-functionality by enabling external interfaces to serve dual purposes: their original communication functions during normal operation and test signal output functions during testing. The test signal routing hierarchy allows the same physical interface to be dynamically configured for either data communication or test signal acquisition, eliminating the need for separate dedicated test output paths and thereby reducing die space occupation while maintaining debuggability
2Reliability
If dedicated test signal output paths are implemented, then internal operational signals can be acquired for debugging and testing, but the manufacturing cost increases
Solution Approach 1:
The patent reduces manufacturing cost by making existing external interfaces multi-functional. Instead of adding dedicated test output paths that会增加 manufacturing complexity and cost, the invention configures the test signal routing hierarchy to utilize already-present communication interfaces, thereby achieving debuggability without additional manufacturing expenses
3Area of stationary object
If MUXs are used to route test signals, then the number of output paths is reduced, but the circuit complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the test signal routing hierarchy with MUXs and control logic during circuit design and fabrication. The control registers and routing structures are built-in advance, allowing simple runtime configuration through software or control signals rather than requiring complex dynamic reconfiguration, thereby reducing operational complexity despite the added structural elements
Data Source
AI summary
Methods and structure are provided for routing internal operational signals of a circuit for output via an external interface. The structure includes an integrated circuit. The integrated circuit comprises a block of circuitry components operable to generate internal operational signals for performing designated functions during normal operation of the circuit, a control unit, a test signal routing hierarchy, and an external interface. The test signal routing hierarchy is coupled to receive the internal operational signals and controllably selects the internal operational signals for acquisition and applies them to the control unit. The external interface provides communications between the integrated circuit and an external device during normal operation of the integrated circuit. The control unit receives the selected internal operational signals from the test signal routing hierarchy, and applies the selected internal operational signals to the external interface during normal operation of the integrated circuit.