Data Interface Timing Calibration Using Mission and Reference Paths
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Solution Overview
Problem
High clock rates and transmission line effects in integrated circuit systems lead to changes in signal timing, causing skew and jitter issues between data bits and strobe signals, which existing technologies fail to address dynamically and efficiently without disrupting system operation.
Innovation Solution
A continuously adaptive timing calibration mechanism is implemented, where a mission data path is calibrated using a reference path, allowing for dynamic re-calibration by adjusting delay settings without interrupting signal traffic, and utilizing multiple parallel calibrations to speed up the process and minimize jitter effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dynamic re-calibration is performed during system operation, then timing accuracy is improved, but system complexity increases
Solution Approach 1:
The system is divided into two separate paths: a mission data path for normal operations and a reference path for calibration operations. This segmentation allows calibration to be performed independently without affecting mission operations, enabling dynamic re-calibration while maintaining system simplicity.
Solution Approach 2:
A calibration controller acts as an intermediary that manages both the mission path and reference path. It determines calibration needs, controls reference path operations, and transfers delay parameters between paths, thereby coordinating the complex calibration process without requiring direct intervention in the mission path.
2Reliability
If frequent re-calibration is performed, then timing skew is reduced, but signal traffic interruption increases
Solution Approach 1:
The reference path performs calibration operations in advance and independently of the mission path. The calibration controller determines optimal delay parameters through reference path calibration before they are needed for mission operations, allowing frequent re-calibration without interrupting signal traffic on the mission path.
Solution Approach 2:
The reference path serves as a copy or model of the mission path for calibration purposes. By performing calibration on the reference path and then transferring the determined delay parameters to the mission path, the system achieves frequent re-calibration capability without disrupting actual data transmission.
3Productivity
If multiple parallel calibrations are implemented, then calibration speed is improved, but device complexity increases
Solution Approach 1:
The calibration process is segmented into multiple parallel operations on the reference path. Multiple delay parameters can be calibrated simultaneously through separate calibration operations, increasing calibration speed without requiring parallel mission path operations.
Solution Approach 2:
The reference path is designed to be multi-functional, serving both as a calibration target and as a source for determining delay parameters. The same reference path infrastructure supports multiple parallel calibration operations, providing universal functionality that increases productivity without proportionally increasing complexity.
Data Source
AI summary
Circuits and methods for implementing a continuously adaptive timing calibration training function in an integrated circuit interface are disclosed. A mission data path is established where a data bit is sampled by a strobe. A similar reference data path is established for calibration purposes only. At an initialization time both paths are calibrated and a delta value between them is established. During operation of the mission path, the calibration path continuously performs calibration operations to determine if its optimal delay has changed by more than a threshold value. If so, the new delay setting for the reference path is used to change the delay setting for the mission path after adjustment by the delta value. Circuits and methods are also disclosed for performing multiple parallel calibrations for the reference path to speed up the training process.