Device Family: Stratix® V GS, Stratix® V GT, Stratix® V GX

Type: Answers

Area: Intellectual Property


Last Modified: May 25, 2017
Version Found: v16.1
Bug ID: FB: 409881;

Why does the runt statistics register of Legacy 40/100G Ethernet IP core read back as "X" in simulation?

Description

Due to a change in runt handling behavior in Quartus® Prime v16.1, the runt statistics register may read back as "X" in simulation in the Legacy 40/100G Ethernet Megacore®.

Normal core behavior is not affected, but when running the KR4 example testbench, the following messages may be seen:

# DUT 1 Sent                1027 packets
# DUT 2 Received           1027 packets
# Runts in RX data
# DUT 2 Sent                1027 packets
# DUT 1 Received            1027 packets
# Runts in RX data

These messages can be safely ignored.

Workaround/Fix

This problem will be fixed in a future version of the Quartus prime software.