F-Tile Architecture and PMA and FEC Direct PHY IP User Guide

ID 683872
Date 11/04/2024
Public
Document Table of Contents

3.5. Bit Mapping for PMA and FEC Mode PHY TX and RX Datapath

The tx_paallel_data bit ad x_paallel_data bit width depeds o the PMA width ad Numbe of PMA laes IP paametes. Use the followig equatio to detemie the total tx_paallel_data o x_paallel_data bit width:

29

Total tx_paallel_data o x_paallel_data Bit Width Equatio:

tx/x_paallel_data[(80*N*X)-1:0]

Whee:

  • N = Numbe of PMA laes value fom 1 to 16.
  • X = Numbe of steams fo the PMA cofiguatio. Depedig o PMA width, X ca be 1, 2, o 4.

Refe to Vaiables Defiig Bits fo the Itefacig Pots i Pot ad Sigal Refeece fo full vaiable defiitios.

The tx/x_paallel_data sigals iclude the valid paallel data bits ad othe fuctioality bits, such as the data valid bit, the wite eable fo TX coe iteface FIFO i elastic mode bit, the RX deskew bit, ad the aligmet make bits (fo FEC mode). These sigals tavel to ad fom the FPGA fabic to the F-tile, ad ae clocked by the same paallel clock. This paallel clock ca be a PMA clock o System PLL clock.

Example 1: Total tx/x_paallel_data Bit Width with 2 PMA Laes (N=2) ad 8-bit PMA Width (X=1)

tx_paallel_data [(80*2*1)-1:0] = tx_paallel_data [159:0]
x_paallel_data [(80*2*1)-1:0] = x_paallel_data [159:0]

Example 2: Total tx/x_paallel_data Bit Width with 4 PMA Laes (N=4) ad 64-bit PMA Width (X=2)

tx_paallel_data [(80*4*2)-1:0] = tx_paallel_data [639:0]
x_paallel_data [(80*4*2)-1:0] = x_paallel_data [639:0]

Paallel Data Mappig ifomatio fo TX ad RX

If the PMA width is less tha o equal to 32, D=PMA width.

If the PMA width is 64 o 128, D=32.

The lowe case x is defied as x=0 to X-1. Fo a give lae, ad give steam x, you ca calculate the TX ad RX paallel data ifomatio accodig to the followig tables:

Table 59.  PMA Diect Mode TX Paallel Data Ifomatio Calculatios (Eable Double width tasfe = 1)
TX Paallel Data MSB LSB
Wite Eable fo TX Coe FIFO i Elastic Mode 30 79 + (80 * x) +(80 * * X)
TX Data (Uppe Data bits) (40 + D-1) + (80 * x) + (80 * * X) 40 + (80 * x) + (80 * * X)
TX PMA Iteface Data Valid Bit 31 32 38 + (80 * x) + (80 * * X)
TX Data (Lowe Data bits) D-1 + (80 * x) + (80 * * X) 0 + (80 * x) +(80 * * X)
Table 60.  PMA Diect Mode RX Paallel Data Ifomatio Calculatios (Eable Double width tasfe = 1)
RX Paallel Data MSB LSB
Data valid fo RX Coe FIFO i Elastic Mode 33 79 + (80 * x) + (80 * * X)
RX Deskew 34 78 + (80 * x) + (80 * * X)
RX Data (Uppe Data bits) (40 + D-1) + (80 * x) + (80 * * X ) 40 + (80 * x) + (80 * * X)
RX PMA Iteface Data Valid Bit 29 38 + (80 * x) + (80 * * X)
RX Data (Lowe Data bits) D-1 + (80 * x) + (80 * * X) 0 + (80 * x) + (80 * * X)
Table 61.  PMA Diect Mode TX Paallel Data Ifomatio Calculatios (Eable Double width tasfe = 0)
TX Paallel Data MSB LSB
Wite Eable fo TX Coe FIFO i Elastic Mode 33 79 + (80 *)
TX PMA Iteface Data Valid Bit 29 30 38 + (80 *)
TX Data D-1 + (80 *) 0 + (80 *)
Table 62.  PMA Diect Mode RX Paallel Data Ifomatio Calculatios (Eable Double width tasfe = 0)
RX Paallel Data MSB LSB
Data valid fo RX Coe FIFO i Elastic Mode 33 79 + (80 *)
RX PMA Iteface Data Valid Bit 29 38 + (80 *)
RX Data D-1 + (80 *) 0 + (80 *)
Table 63.  FEC Diect Mode TX Paallel Data Ifomatio Calculatios (Eable Double width tasfe = 1)
TX Paallel Data MSB LSB
Aligmet Make 35 77 + (80 * x) +(80 * * X)
TX Data (Uppe 33 bits) 72 + (80 * x) + (80 * * X) 40 + (80 * x) + (80 * * X)
TX PMA Iteface Data Valid Bit 29 30 38 + (80 * x) + (80 * * X)
Aligmet Make 33 37 + (80 * x) + (80 * * X)
TX Data (Lowe 31 bits) 32 + (80 * x) + (80 * * X) 2 + (80 * x) + (80 * * X)
Syc Head 1 + (80 * x) + (80 * * X) 0 + (80 * x) + (80 * * X)
Table 64.  FEC Diect Mode RX Paallel Data Ifomatio Calculatios (Eable Double width tasfe = 1)
RX Paallel Data MSB LSB
RX Deskew 36 78 + (80 * x) + (80 * * X)
RX Data (Uppe 33 bits) 72 + (80 * x) + (80 * * X) 40 + (80 * x) + (80 * * X)
RX PMA Iteface Data Valid Bit 29 37 38
Aligmet Make 32 37
RX Data (Lowe 31 bits) 32 + (80 * x) + (80 * * X) 2 + (80 * x) + (80 * * X)
Syc Head 1 + (80 * x) + (80 * * X) 0 + (80 * x) + (80 * * X)
29 This sectio explais the bit mappig of TX ad RX paallel data if the Povide sepaate iteface fo each PMA optio is disabled. If the Povide sepaate iteface fo each PMA optio is eabled, efe to the itoductio of Sigal ad Pot Refeece to view the bit mappig diffeeces.
30 Applicable oly whe usig PMA clockig mode oly ad whe TX/RX coe FIFO is i elastic mode.
31 Applicable oly whe usig System PLL clockig mode.
32 Fo all boded cofiguatios, all TX PMA Iteface Data Valid bits must be asseted at the same cycle of tx_coeclki clock.
33 Split Iteface fo datapath Memoy mapped Avalo iteface oly suppoted fo PMA Diect mode.
34 Applicable oly whe usig PAM4 ad X=2 o 4
35 The two aligmet makes i this table must be dive togethe by the same sigal.
36 Applicable oly whe usig NRZ/PAM4 whe X=2 o 4 o N > 1
37 Oly oe pe system