Answers Database

M1.4 CPLD: Some designs which used to fit in M1.3 failed with M1.4.


Record #2910

Product Family:  Software

Product Line:  CPLD Implementation

Problem Title:
M1.4 CPLD: Some designs which used to fit in M1.3 failed with M1.4.


Problem Description:
Keywords: fit, multi-level logic optimization

Urgency: standard

General Description:

Some CPLD designs that fit with M1.3 in a particular device won't fit any more
with M1.4. In some cases the fitter will fail to meet the Timing
Specifications as well.

For backward compatibility with M1.3 do the following:


Solution 1:

Through the Design Manager invoke the Flow Engine. Go to Setup -> Options. Click

on Edit Template button in the Program Option Template box. Go to the Advanced
Optimization TAB of the XC9500 Implementation Options Template. Turn the
Multi-level Logic Optimization off by clicking on the button on the left of the
text.



Solution 2:

In the Advanced Optimization TAB, also change the "Collapsing Pterm Limit" value
 to 15.



End of Record #2910