Multilane Link Deskew With FIFO-Based Clock Domain Crossing
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Solution Overview
Problem
Conventional systems face challenges in minimizing latency during clock domain crossing for data transmission over multilane links due to the need for multiple processing cycles to synchronize data streams across different lanes and with the destination clock domain.
Innovation Solution
The data streams are clocked into FIFO deskew buffers using recovered clock signals and then clocked out using the target clock domain signal, eliminating the need for a separate clock domain crossing buffer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If data is transmitted over a multilane link with physically different lane lengths, then data skew occurs between lanes, but using conventional deskewing methods increases latency
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal read timing values in lookup tables before data arrives. The deskew buffer uses these pre-computed timing values to immediately correct skew without requiring complex real-time analysis, thus reducing latency while achieving signal synchronization.
Solution Approach 2:
The patent introduces deskew buffers as intermediary elements between the skewed lane inputs and the destination clock domain. These buffers act as mediators that absorb the timing differences between lanes and provide synchronized output, resolving the contradiction between skew correction and latency reduction.
2Reliability
If multiple FIFO buffers are used for deskewing and clock domain crossing, then synchronization is achieved, but device complexity increases
Solution Approach 1:
The patent merges the deskewing function and clock domain crossing function into a single integrated FIFO buffer structure. Instead of using separate buffers for each function, the invention combines them into one unified buffer that performs both deskewing and clock domain translation, thereby reducing device complexity while maintaining synchronization reliability.
Solution Approach 2:
The patent makes the FIFO buffer universal by designing it to perform multiple functions: deskewing skewed signals, synchronizing to the destination clock domain, and enabling data transfer between clock domains. This multi-functional design eliminates the need for multiple specialized buffers, reducing overall system complexity.
Data Source
AI summary
Systems and methods for communicating data via a multilane data link from a first clock domain to a second clock domain, where the data streams of a multilane link are clocked into FIFO deskew buffers using clock signals that are recovered from the data streams themselves. Each data stream is clocked into the deskew buffer with the clock signal recovered from that data stream. The data is clocked out of the deskew buffers using the clock signal of a target clock domain so that the data streams clocked out of the deskew buffers are synchronized with each other and with the clock signal of the target clock domain (the target clock signal) to eliminate the need for a separate clock domain crossing buffer.