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AR# 4141

Orcad Express: Using TIMESPEC to set global attributes in Xilinx

Description

Keywords: Orcad, Express, Windows, timespec, dummy

Urgency: standard

General Description: How can I use the TIMESPEC part from my Xilinx library to
specify global timing constraints when using Orcad Express?

Solution

In order for Express to recognize the TIMESPEC part, it must
place a "dummy" pin in the netlist while compiling. However,
you must remove this dummy pin (and any associated net) from
the netlist before building/implementing your design, in order
to avoid errors in XACTStep and M1. Follow these steps:


1.Place the TIMESPEC part and assign the appropriate Xilinx
timing attributes as you would normally.

2.Compile the design with the Compile command.

3.If you are using XACTStep, open the resulting XNF, search
for the string "TIMESPEC" and remove the line:
PIN, dummy, I, dummy
that immediately follows the TIMESPEC instance. For example:

Before:
LCANET, 6
PROG, EXPRESS.EXE, 7.10, 01/28/98
PART, 5206PC84-5
SYM,u1,TIMESPEC,LIBVER=2.0.0
PIN, dummy, I, dummy
EOF
END

After:
LCANET, 6
PROG, EXPRESS.EXE, 7.10, 01/28/98
PART, 5206PC84-5
SYM,u1,TIMESPEC,LIBVER=2.0.0
EOF
END



4.If you are using M1, search for the string "TIMESPEC" and
remove the sections marked with an asteric "*" in the following
example:

(edif mydesign (edifVersion 2 0 0) (edifLevel 0)
(keywordMap (keywordLevel 0))
(status (written (timestamp 1998 01 29 00 15 48)
(program "EXPRESS.EXE" (version "7.1" ) ) ) )
(external OrCAD_LIBRARY (edifLevel 0)
(technology (numberDefinition (scale 1 1 (unit distance))))

(cell TIMESPEC (cellType generic)
(view netlistview (viewType netlist)
(interface
* (port DUMMY (direction input))
)
))
)

(library MAIN_LIBRARY (edifLevel 0)
(technology (numberDefinition (scale 1 1 (unit distance))))

(cell SCHEMATIC1 (cellType generic)
(view netlistview (viewType netlist)
(interface)

(contents

(instance U1 (viewRef netlistview
(cellRef TIMESPEC (libraryRef OrCAD_LIBRARY) ) )
(property XIL_DEVICE (string "TIMESPEC"))
)

* (net DUMMY
* (joined
* (portRef DUMMY (instanceRef U1) )
* )
* )

)
))
) (design MYDESIGN (cellRef SCHEMATIC1 (libraryRef MAIN_LIBRARY) )) )



At this point you can Build the design normally. Express will relay
the global attributes specified on the TIMESPEC component to the
appropriate Xilinx implementation tool (XACTStep or M1).

For more Orcad related solutions, see the Orcad web pages:
http://www.orcad.com/odn/
http://www.orcad.com/techserv/vendors/xilinxm1.htm

AR# 4141
Date Created 08/31/2007
Last Updated 10/06/2008
Status Archive
Type General Article