L- and H-Tile Transceiver PHY User Guide

ID 683621
Date 7/20/2022
Public
Document Table of Contents

2.5.1.11. Preset Mappings to TX De-emphasis

Table 115.   Intel® Stratix® 10 Preset Mappings to TX De-emphasis
Preset C+1 C0 C-1 VOD 38 First Pre-tap First Post-tap
P0 001111 101101 000000 31 -15
P1 001010 110010 000000 31 -10
P2 001100 110000 000000 31 -12
P3 001000 110100 000000 31 -8
P4 000000 111100 000000 31
P5 000000 110110 000110 31 -6
P6 000000 110100 001000 31 -8
P7 001100 101010 000110 31 -6 -12
P8 001000 101100 001000 31 -8 -8
P9 000000 110010 001010 31 -10
P10 010110 100110 000000 31 -20

Use the pipe_g3_txdeemph[17:0] port to select the transmitter de-emphasis. The 18 bits specify the following coefficients:

  • [5:0]: C-1
  • [11:6]: C0
  • [17:12]: C+1

The PCIe Gen3 full swing (FS) value is 60, and the PCIe Gen3 low frequency (LF) value is 20.

Intel recommends transmitting Preset P8 coefficients for the Intel® Stratix® 10 receiver to recover data successfully.

38 The VOD setting is fixed at 31 (for example, FS/2 + 1 = 60/2 + 1) for both full-swing mode operation and reduced-swing mode operation. FS denotes the Full Swing value.

Did you find the information on this page useful?

Characters remaining:

Feedback Message