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AR# 4678

map 1.4:ERROR:baste:263 - The LOC constraint "P21" (a IOB location) is not valid..

Description

Keywords: map, alliance, leonardo

Urgency: Hot

General Description:
Trying to source a global clock buffer from a non-dedicated clock I/O. In VHDL, by making a signal assignment to the input signal in order to force an ibuf
between the input signal and the clock buffer.

When the design is run through MAP, M1 falls over with the error:

ERROR:baste:263 - The LOC constraint "P21" (a IOB location) is not valid for
symbol "reset_200msn.PAD" (pad signal=reset_200msn), which is being mapped
to the following site types: CLKIOB

Solution

Leonardo optimizes the ibuf out which is reflected in the resulting netlist.

The reason this has occurred is because the netlist dictates
that the clock signal comes into the device and directly into
the input of a global buffer. However, because the clock
signal is not placed to an IOB with this direct access to a
global buffer, this is an illegal connection.

The solution is to insert an input buffer between the pad and
the global buffer.
AR# 4678
Date Created 09/24/1998
Last Updated 03/27/2000
Status Archive
Type General Article