R-tile Avalon® Streaming Intel® FPGA IP for PCI Express* User Guide

ID 683501
Date 6/20/2022

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4.4.4. Deskew Signals

In PIPE Direct mode, the PHY wrapper removes any lane-to-lane skew introduced while crossing the EMIB. A dedicated deskew marker is used for detecting and compensating for any multi-lane skew introduced by EMIB. The deskew logic can account for a maximum of up to 3 cycles of parallel skew. After a cold/warm/hot reset or CvP update, the deskew process will start.

The user application logic needs to send a deskew marker every 16 clock cycles for the purpose of deskewing the data on the EMIB channels. The PHY deskew logic will run the deskew process every time it receives the deskew marker.

Table 80.  EMIB TX Deskew Grouping for R-tile Topologies
PIPE Direct Tx Deskew Bundle Octet 1 Octet 0
Lane 15 Lane 14 Lane 13 Lane 12 Lane 11 Lane 10 Lane 9 Lane 8 Lane 7 Lane 6 Lane 5 Lane 4 Lane 3 Lane 2 Lane 1 Lane 0
1X16 Octet1_Dsk_0 Octet0_Dsk_0
2X8 Octet1_Dsk_0 Octet0_Dsk_0
4X4 Octet1_Dsk_2 Octet1_Dsk_0 Octet0_Dsk_2 Octet0_Dsk_0
8X2 Octet1_Dsk_3 Octet1_Dsk_2 Octet1_Dsk_1 Octet1_Dsk_0 Octet0_Dsk_3 Octet0_Dsk_2 Octet0_Dsk_1 Octet0_Dsk_0
16X1 No Tx Deskew
2X4; 1X8 Octet1_Dsk_2 Octet1_Dsk_0 Octet0_Dsk_0
4X2; 1X8 Octet1_Dsk_3 Octet1_Dsk_2 Octet1_Dsk_1 Octet1_Dsk_0 Octet0_Dsk_0
8X1; 1X8 No Tx Deskew Octet0_Dsk_0
1X8; 2X4 Octet1_Dsk_0 Octet0_Dsk_2 Octet0_Dsk_0
4X2; 2X4 Octet1_Dsk_3 Octet1_Dsk_2 Octet1_Dsk_1 Octet1_Dsk_0 Octet0_Dsk_2 Octet0_Dsk_0
8X1; 2X4 No Tx Deskew Octet0_Dsk_0 Octet0_Dsk_0
1X8; 4X2 Octet1_Dsk_0 Octet0_Dsk_3 Octet0_Dsk_2 Octet0_Dsk_1 Octet0_Dsk_0
2X4; 4X2 Octet1_Dsk_2 Octet1_Dsk_0 Octet0_Dsk_3 Octet0_Dsk_2 Octet0_Dsk_1 Octet0_Dsk_0
8X1; 4X2 No Tx Deskew Octet0_Dsk_3 Octet0_Dsk_2 Octet0_Dsk_1 Octet0_Dsk_0
1X8; 8X1 Octet1_Dsk_0 No Tx Deskew
2X4; 8X1 Octet1_Dsk_2 Octet1_Dsk_0 No Tx Deskew
4X2; 8X1 Octet1_Dsk_3 Octet1_Dsk_2 Octet1_Dsk_1 Octet1_Dsk_0 No Tx Deskew