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AR# 1051

XNFPREP: Error 3526: Illegally inverted pin with XBLOX SYNC_RAM symbol

Description

Keywords: xnfprep, error 3526, xblox, RAM

Urgency: Standard

General Description:

During compilation of a XC4000E design containing an XBLOX SYNC_RAM
component, XNFPrep may give the following error:

XNFPREP: ERROR 3526:
The pin 'D' on the symbol <symbol name> (type = RAMS, output signal =
[signal name]) is illegally inverted. This pin in non-invertible.

This error is occurs while placing either an INVBUS symbol or INV symbol on
the WR_CLK pin to clock the synchronous RAM on the falling edge. XBLOX
pushes the inversion onto the device pin instead of leaving the inverter
separate as it should.

Solution

Place an X (explicit) property on the net between the INV/INVBUS and the
SYNC_RAM. This will prevent the inverter from being absorbed into the D
pin of the synchronous RAM.
AR# 1051
Date Created 06/10/1996
Last Updated 05/24/1999
Status Archive
Type General Article