V-Series Transceiver PHY IP Core User Guide

ID 683171
Date 7/26/2022
Public
Document Table of Contents

4.4.1. 10GBASE-KR Link Training Parameters

The 10GBASE-KR variant provides parameters to customize the Link Training parameters.
Table 25.  Link Training Settings
Name Value Description
Enable Link Training On/Off

When you turn this option On, the core includes the link training module which configures the remote link-partner TX PMD for the lowest Bit Error Rate (BER). LT is defined in Clause 72 of IEEE Std 802.3ap-2007.

Enable daisy chain mode On/Off

When you turn this option On, the core includes support for non-standard link configurations where the TX and RX interfaces connect to different link partners. This mode overrides the TX adaptation algorithm.

Enable microprocessor interface On/Off

When you turn this option On, the core includes a microprocessor interface which enables the microprocessor mode for link training.

Maximum bit error count 15, 31,63, 127, 255

Specifies the maximum number of errors before the Link Training Error bit (0xD2, bit 4) is set indicating an unacceptable bit error rate. You can use this parameter to tune PMA settings. For example, if you see no difference in error rates between two different sets of PMA settings, you can increase the width of the bit error counter to determine if a larger counter enables you to distinguish between PMA settings.

Number of frames to send before sending actual data 127, 255

Specifies the number of additional training frames the local link partner delivers to ensure that the link partner can correctly detect the local receiver state.

PMA Parameters
VMAXRULE

0-63

Specifies the maximum VOD. The default value is 60 which represents 1200 mV.

VMINRULE

0-63

Specifies the minimum VOD. The default value is 9 which represents 165 mV.

VODMINRULE

0-63

Specifies the minimum VOD for the first tap. The default value is 24 which represents 440mV.

VPOSTRULE

0-31

Specifies the maximum value that the internal algorithm for pre-emphasis will ever test in determining the optimum post-tap setting. The default value is 31.

VPRERULE

0-15

Specifies the maximum value that the internal algorithm for pre-emphasis will ever test in determining the optimum pre-tap setting. The default value is 15.

PREMAINVAL

0-63

Specifies the Preset VOD Value. Set by the Preset command as defined in Clause 72.6.10.2.3.1 of the link training protocol. This is the value from which the algorithm starts. The default value is 60.

PREPOSTVAL

0-31

Specifies the preset Pre-tap Value. The default value is 0.

PREPREVAL

0-15

Specifies the preset Post-tap value. The default value is 0.

INITMAINVAL

0-63

Specifies the Initial VOD Value. Set by the Initialize command in Clause 72.6.10.2.3.2 of the link training protocol. The default value is 52.

INITPOSTVAL

0-31

Specifies the initial first Post-tap value. The default value is 30.

INITPREVAL

0-15

Specifies the Initial Pre-tap Value. The default value is 5.