Answers Database

M1.4 Ngdbuild - Schematic DRIVE property for 4KXV devices is not being passed to map and is lost.


Record #3113

Product Family:  Software

Product Line:  Merged Core

Problem Title:
M1.4 Ngdbuild - Schematic DRIVE property for 4KXV devices is not being
passed to map and is lost.



Problem Description:
The schematic DRIVE property is being dropped by ngdbuild
and lost so that map does not configure output buffers
properly.This can be verified by examining the IOBs in
question in EPIC using the Logic Block Editor.

Reference # 101935


Solution 1:

This problem can be worked around in one of two ways:

1. The DRIVE property can be set in the .ucf constraints
   file prior to mapping:

   NET "*" DRIVE=24 ; (Where "*" is a string that matches
   output net names)

   or

   INST "*" DRIVE=24 ; (Where "*" is a string that matches
   output buffer names)

2. The IOB configuration can be changed after mapping using
   EPIC, either manually using the the Logic Block Editor,
   or by running the following global commands:

   A. Load design in EPIC
   B. Type "a" to open EPIC command line window.
   C. Run command "select comp *" (Matching string can be
      varied to match IOBs that need to be changed)
   D. Run command "setattr config DRIVE:24" (This will change
      the drive strength for all IOBs selected).

In both work arounds, it does no harm for the matching strings
to match non-IOB objects.



End of Record #3113