Answers Database

XNFMERGE 5.2.0: FAST, MEDFAST, MEDSLOW properties dropped when attachedto OFD/OUTFF/OBUF/OBUFT macros


Record #1568

Product Family:  Software

Product Line:  FPGA Core

Problem Title:
XNFMERGE 5.2.0:	FAST, MEDFAST, MEDSLOW properties dropped when
attachedto OFD/OUTFF/OBUF/OBUFT macros



Problem Description:
There is currently a bug in XNFMERGE 5.2.0 where FAST, MEDFAST, and MEDSLOW
properties are lost when they are attached to OFD, OUTFF, OBUF, or OBUFT
macros in schematic designs done in all schematic entry platforms, except
for Viewlogic.	The problem is not seen in Viewlogic because the Viewlogic
output buffer and register macros have a special EXT property attached to the
underlying buffer and register primitives that define them to be external.


Solution 1:

The workaround is to avoid the use of macros when specifying FAST, MEDFAST,
or MEDSLOW slew rates in your design.

For 4000E:  attach the attribute to OBUFT, OBUF, or OFDX only
For 3000A:  attach the attribute to OBUFT, OBUF, or OFD

Attaching the attribute to a multiple-component macro such as OFD16,
for example will not work--you must instantiate each output individually.



Solution 2:

You can also add these properties manually to the appropriate EXT records
in the .XTF file produced by XNFPREP.

Example:

Say you want an output signal called "sig1" to go through
an output configured in FAST mode:


original EXT record:

  EXT, sig1, O,

Modified EXT record:

  EXT, sig1, O,, FAST


Note that the two commas following the "O" are required.  The first
comma is a reserved delimiter for the LOC= ("location") field.



To set it to MEDFAST:

  EXT, sig1, O,, MEDFAST


To set it to MEDSLOW:

  EXT, sig1, O,, MEDSLOW



End of Record #1568