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AR# 32544

Virtex-4 Embedded Tri-mode Ethernet MAC Wrapper - Implementation of MII interface might fail in MAP due to I/O banking rules

Description

When a design with MII interface is implemented, intermittent failures occur in MAP with the following error:

"ERROR:Place:864 - Incompatible IOB's are locked to the same bank 2 Conflicting IO Standards are:
IO Standard 1: Name = LVCMOS25, VRR, VCCO = 2.50, TERM = NONE
List of locked IOB's: HOSTCLK

IO Standard 2: Name = LVTTL, VREF = NR, VCCO = 3.30, TERM = NONE
List of locked IOB's: MII_TX_CLK_1

These IO Standards are incompatible due to VCCO mismatch."

Solution

To avoid this error, add the following constraints in the UCF:

INST "MII_TX_CLK_1" LOC = "Bank4";
INST "MII_TX_CLK_0" LOC = "Bank4";
INST "MII_RX_CLK_1" LOC = "Bank4";
INST "MII_RX_CLK_0" LOC = "Bank4";

AR# 32544
Date Created 04/21/2009
Last Updated 12/15/2012
Status Active
Type General Article