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AR# 5085

FPGA/Design Compiler: TNM attribute created from DC2NCF causes warnings in NGDBUILD

Description

Keywords: basts:158, DC2NCF, TNM, TNM_NET, create_clock

Urgency: Standard

Description:

Using M1.5 DC2NCF with Synopsys, the following NCF notaction is
created for a create_clock command:

TIMESPEC TS_CLOCK = PERIOD : "CLOCK": 50 : HIGH : 25;
NET "CLOCK" TNM = "CLOCK";

This causes the following warning in the M1.5 version of NGDBUILD:

WARNING:basts:158 - PERIOD TIMESPEC 'TS_CLOCK' has TIMEGRP 'CLOCK'
which contains only PAD elements. This capability will soon be obsolete, as it has been replaced by the TNM_NET constraint.

Solution


The constraint still works properly; however, if you wish to see
these warnings disappear in NGDBUILD, you can manually change the
TNM constraint to a TNM_NET constraint as following:

TIMESPEC TS_CLOCK = PERIOD : "CLOCK": 50 : HIGH : 25;
NET "CLOCK" TNM_NET = "CLOCK";


The warning goes away, and the timespec will still translate
properly.

This change for DC2NCF has been proposed for the next release of
the software, M2.1.
AR# 5085
Date Created 08/31/2007
Last Updated 10/05/2008
Status Archive
Type General Article