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AR# 21375

LogiCORE Ethernet Statistics v1.1 and v2.1 Core - Virtex-4 Verilog simulations in ModelSim PE cause memory collision errors

Description

In performing Verilog UniSim or SimPrim simulations of the LogiCORE Ethernet Statistics v1.1 and v2.1 Core targeted to Virtex-4 in ModelSim PE, the following memory collision error might occur: 

 

"# Memory Collision Error on RAMB16 : testbench.dut.statistics_gathering.\BU2/U0/ethernet_statistics_64bit/store_lower32_bits .collision_message_task at simulation time 7080.000 ns.  

 # A read was performed on address 04c0 (hex) of port B while a write was requested to the same address on port A. The write will be successful; however, the read value on port B is unknown until the next CLKB cycle."

Solution

Note that this fails only in MTI PE versions of ModelSim (MTI SE simulations work successfully). This is a ModelSim issue and not a core issue. ModelSim is currently investigating the issue. 

 

This Answer Record will be updated as new information becomes available.

AR# 21375
Date Created 09/04/2007
Last Updated 05/19/2014
Status Archive
Type General Article