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AR# 4173

M1.5 9500XL Fitter/Library - Clock-enable p-term not used for FDPE in Cadence and Mentor schematics.


Keywords: CPLD, Fitter, 9500, 9500XL, Mentor, Cadence, Concept, FDPE, CE

Urgency: Standard

General Description:
In M1.5, the symbols "FDCE" and "FDPE" in the 9500/XL schematic libraries are
supposed to be primitives and cause the 9500XL fitter to use the macrocell clock-
enable p-term to implement the CE-input. In Cadence (Concept and Verilog) and
Mentor libraries, FDPE is incorrectly configured as a macro; its CE input is
implemented as gate logic on the flip-flop D-input path.


To implement a flip-flop with an asynchronous preset and clock-enable using the
9500XL clock- enable p-term, use a FDCE primitive in negative logic form instead of
FDPE. Invert the D-input and Q-output of the FDCE, and connect your asynchronous
preset to its CLR input. Also, apply the INIT property to the FDCE, indicating the
opposite power-on state than you would normally specify for a FDPE.

This has been fixed as of version 2.1i.
AR# 4173
Date Created 08/31/2007
Last Updated 10/06/2008
Status Archive
Type General Article