Ethernet Transmitter Tap Zeroing Under KR Training Limits
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Solution Overview
Problem
The existing IEEE 802.3 KR Training protocol lacks a clear method to individually set the pre and post-taps of a link partner's transmitter to a zero gain setting, leading to ambiguity in transmitter tap status during training.
Innovation Solution
A system and method that uses iterative commands to maintain the center tap at its maximum setting while adjusting the pre and post-taps to zero, utilizing IEEE 802.3 Clause 72 messages to manage voltage gain taps and detect limit signals, ensuring accurate zero setting of selected taps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the KR Training protocol is used to adjust transmitter taps, then the transmitter taps can be manipulated to optimize signal quality, but there is no method to individually set pre and post-taps to zero gain setting
Solution Approach 1:
The patent segments the tap adjustment process into distinct phases: first adjusting the pre-tap or post-tap toward zero, then adjusting the center tap to maximum. This segmentation allows individual control of each tap parameter, resolving the inability to individually set pre and post-taps to zero while maintaining protocol manageability.
Solution Approach 2:
The patent introduces dynamic adjustment sequences where the center tap is adjusted in response to pre/post-tap changes. The protocol dynamically determines when to adjust which tap based on current settings, enabling flexible individual zeroing of pre/post-taps while automatically optimizing the center tap setting.
2Reliability
If the center tap is maximized to optimize signal quality, then the pre and post-taps cannot be decreased due to maximum swing voltage limit
Solution Approach 1:
The patent applies preliminary action by first adjusting the pre-tap or post-tap toward zero before maximizing the center tap. This sequence ensures that the differential voltage limits are not violated, as the pre/post-tap adjustments are made while the center tap is still at its initial value, leaving headroom for subsequent center tap maximization.
Solution Approach 2:
The patent inverts the conventional approach by not maximizing the center tap first and then adjusting pre/post-taps. Instead, it adjusts pre/post-taps first and then maximizes the center tap, reversing the traditional sequence to avoid voltage limit conflicts and enable individual zeroing of pre/post-taps.
3Reliability
If the PRESET command is used to set center tap to maximum and pre/post-taps to zero, then the center tap is optimized, but the pre and post-taps cannot be individually controlled
Solution Approach 1:
The patent replaces the monolithic PRESET command with segmented adjustment sequences. Instead of forcing all taps to predetermined values, the protocol segments the adjustment into: (1) adjusting the selected pre-tap or post-tap toward zero, and (2) adjusting the center tap to maximum. This segmentation enables individual control of pre/post-taps while maintaining center tap optimization.
Solution Approach 2:
The patent applies partial action by adjusting only the necessary taps in a controlled sequence rather than applying the full PRESET command that forces all taps to extreme values. The protocol performs partial adjustments - setting pre/post-tap to zero when needed and center tap to maximum - giving precise control over which taps are adjusted and to what values.
Data Source
AI summary
A system and method are provided for zeroing pre and post-tap settings in a link partner using a plurality of voltage gain taps. The method provides a link partner (LP) transmitter. A network-connected local device (LD) selects an LP pre-tap or post-tap. The LD also chooses a zero gain setting for the selected LP tap. In a first iteration, the LD directs the LP to decrease the difference between the selected tap gain setting and the zero setting by 1 step. If a limit signal is not received by the LD, the LP is directed to maximally increase the center tap gain setting until a limit signal is received. The iterations are continued until a limit signal is returned in response to the LD directing the LP to decrease the difference between the selected tap gain setting and the zero setting.