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AR# 14268

4.1i XST - "WARNING:Xst:163 or 164 - Inserting OBUF on port <my_port> driven by tristate(s), possible simulation mismatch"

Description

Keywords: XST, 163, OBUF, 3, tri, state, simulation

Urgency: Standard

General Description:
During the netlist building stage of XST synthesis, the following warning occurs:

"WARNING:Xst:163 - Inserting OBUF on port <my_port> driven by tristate(s), possible simulation mismatch."

or

"WARNING:Xst:164 - Inserting OBUF on port <my_port<2>> driven by tristate(s), possible simulation mismatch."

Solution

This message indicates that XST acknowledges there are multiple internal 3-state buffers driving a single output port. Ensure that the control signals enabling the 3-state outputs are mutually exclusive.

These two warning messages differ only in the fact that "Xst:163" appears for single-bit signals and "Xst:164" appears for bits of buses.
AR# 14268
Date Created 03/21/2002
Last Updated 08/06/2003
Status Archive
Type General Article