Answers Database

M1.3 CPLD: Synopsys set_pad_type -slewrate command causes disconnected OBUF in CPLD.


Record #2654

Product Family:  Software

Product Line:  CPLD Implementation

Problem Title:
M1.3 CPLD: Synopsys set_pad_type -slewrate command causes disconnected
OBUF in CPLD.



Problem Description:
Keywords: synopsys, slewrate, cpld, set_pad_type

Urgency: standard

General Description:

The DC_shell 'set_pad_type -slewrate NONE|HIGH' command
normally used to specify FAST/SLOW outputs for CPLD designs
causes the output pad to become disconnected and trimmed away.
There may be no warning unless all logic back to an input pad
also gets trimmed and produces WARNING nd201 Removing unused
inputs. Otherwise, the trimmed output ports will simply be
missing in the report (.rpt).


Solution 1:

You can also obtain the latest CPLD patches located at:
ftp://ftp.xilinx.com/pub/swhelp/M1.3_alliance/

In this directory you will find epld*.tar.Z

Obtain the correct file with respect to your operating system.

(for example on an HP machine: epldhp121097.tar.Z)

The numbers after the OS represent the date the patch was
updated and can differ at the time this record was created.



Solution 2:

Use a UCF file instead of dc_shell script to specify FAST or
SLOW property, as in 'NET Q1 FAST;'.




End of Record #2654