JTAG Mailbox Scan Event Mode for Asynchronous Reporting
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Solution Overview
Problem
Existing JTAG configurations face inefficiencies in event reporting and transmission, leading to time delays and increased pin requirements, which hinder debugging and diagnostics processes.
Innovation Solution
The implementation of a scan event mode in electronic devices with a JTAG port, where events are automatically mapped to the TDO pin, reducing the need for additional pins and minimizing overhead, and the use of registers to store and forward events efficiently, enabling asynchronous event reporting and prioritization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional pins are added for event reporting in JTAG configuration, then event transmission capability is improved, but device complexity and pin requirements increase
Solution Approach 1:
The patent applies multi-functionality by enabling the existing TDO pin to serve dual purposes: traditional JTAG data output and event reporting. By implementing scan event mode, the TDO pin is configured to automatically report events from the processing stage without requiring dedicated event pins, thus one pin performs multiple functions and device complexity is reduced
Solution Approach 2:
The patent merges the event reporting function with the existing JTAG data output function. By combining event transmission through the TDO pin with the standard JTAG data output capability, the system eliminates the need for separate event pins while maintaining both functionality, thereby reducing overall device complexity
2Ease of operation
If traditional polling method is used for event detection, then implementation simplicity is maintained, but time delays and processing efficiency deteriorate
Solution Approach 1:
The patent implements preliminary action by automatically mapping events to the TDO pin in advance through scan event mode configuration. Events are prepared and positioned for transmission before being detected, eliminating the need for continuous polling and enabling immediate event reporting, thus reducing detection time while maintaining operational simplicity
Solution Approach 2:
The system performs self-service by automatically detecting and reporting events through the scan event mode mechanism. The processing stage itself initiates event transmission without requiring external polling operations, making the system self-sufficient and eliminating time-consuming polling cycles while keeping the implementation straightforward
3Speed
If events are transmitted synchronously with program flow, then processing speed is maintained, but event handling flexibility and responsiveness deteriorate
Solution Approach 1:
The patent applies dynamics by enabling the system to switch between synchronous processing mode and scan event mode dynamically. The TAP controller can transition between normal operation and event scanning based on real-time needs, allowing the system to maintain high processing speed during normal operation while providing flexible event handling capability when required, thus achieving both speed and adaptability
Data Source
AI summary
An electronic device comprises a processing stage, a JTAG port including a test data input pin (TDI), a test data output pin (TDO), a test mode select pin (TMS), a test clock pin (TCK), and a test access port (TAP) controller having a data register (DR) shift state and an instruction register shift (IR) state. The electronic device operates in a scan event mode automatically mapped an incoming event to the TDO pin.