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AR# 67842

10G Ethernet Subsystem IP example design simulation running at 10.309Ghz not 10.3125Ghz

Description

When I measure the line rate of the simulated example design the result is a line rate of 10.309GHz instead of the expected 10.3125GHz.

The comments in the simulation file give the following explanation.

`timescale 1ps / 1ps
`define FRAME_TYP [32*32+32*4+16:1]
// Define the refclk period in ps - in reality this should be 6400 ps = 66*96.969696..
// but that is not possible to model accurately, so use the next closest number...
`define BITPERIOD 98 // Closest even number above 96.969696..
`define PERIODCORECLK 66*98 // this is the clock for 156.25MHz based on bit period of 98ps

Solution

The comments are correct and this is expected behavior.

AR# 67842
Date Created 09/09/2016
Last Updated 09/23/2016
Status Active
Type General Article
Devices
  • Kintex UltraScale
  • Kintex-7
  • Artix-7
  • More
  • Virtex UltraScale
  • Virtex-7
  • Less
Tools
  • Vivado Design Suite
IP
  • AXI 10 Gigabit Ethernet