Clock Domain Crossing Control with Random Delay Against Metastability
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Solution Overview
Problem
The increasing complexity of clock domain crossing (CDC) issues due to the use of various clock frequencies in integrated circuits leads to meta-stability problems during data transmission between asynchronous clock domains, which existing methods have not adequately addressed.
Innovation Solution
An integrated circuit with multiple clock generators and logic circuits that identify meta-stability based on clock signal frequencies, randomly delaying at least one clock signal to mitigate meta-stability, thereby ensuring synchronized communication between logic circuits operating with different clock signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If various clock sources and clock dividers are used to generate clocks of various frequencies, then the adaptability and functionality of the integrated circuit are improved, but the complexity of clock domain crossing increases and meta-stability problems occur
Solution Approach 1:
A clock domain crossing controller is introduced as an intermediary component that manages data transmission between asynchronous clock domains. The controller identifies meta-stability information based on clock signal frequencies and applies random delay control to clock signals, thereby mediating the interaction between different clock domains and reducing meta-stability issues while maintaining support for various clock frequencies.
Solution Approach 2:
The system dynamically adjusts clock signal timing by applying random delay control based on identified meta-stability information. The delay amount varies dynamically according to the specific clock frequency combination and meta-stability conditions, allowing the system to adaptively optimize clock domain crossing for different operating scenarios rather than using a fixed delay approach.
2Adaptability or versatility
If data is transmitted between asynchronous clock domains, then the functionality and communication capability are improved, but meta-stability occurs reducing reliability
Solution Approach 1:
The system performs preliminary identification of meta-stability information based on clock signal frequencies before data transmission occurs. By detecting potential meta-stability conditions in advance, the system can pre-apply appropriate random delay control to clock signals, preventing meta-stability from occurring during the actual data transmission process rather than reacting after the problem arises.
Solution Approach 2:
The clock domain crossing controller performs preliminary analysis of clock frequency relationships and identifies meta-stability risks before enabling data transmission between clock domains. This preliminary action allows the system to configure appropriate delay parameters in advance, ensuring reliable transmission without waiting for meta-stability issues to manifest.
3Reliability
If clock signals are delayed to reduce meta-stability, then the reliability of data transmission is improved, but the clock signal timing precision deteriorates
Solution Approach 1:
The system changes the timing parameter of clock signals by applying controlled random delays. Rather than using a fixed delay value, the delay parameter is dynamically adjusted based on the specific clock frequency combination and identified meta-stability conditions. This parameter change approach resolves meta-stability issues while minimizing the impact on overall timing precision by only delaying enough to break harmful synchronization patterns.
Data Source
AI summary
Provided is an integrated circuit. The integrated circuit includes a plurality of clock generators configured to respectively generate a plurality of clock signals, a plurality of logic circuits configured to operate in synchronization with the plurality of clock signals, and controller circuitry configured to identify meta-stability information based on frequencies of the plurality of clock signals, and configured to control at least one clock generator so that at least one of the plurality of clock signals is randomly delayed in response to the meta-stability information.