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AR# 21525

7.1i XST, Virtex-4 - "Warning:XST:1902 - Value <-255 to 255> for attribute PHASE_SHIFT of instance <inst_name> in unit <unit_name> is not supported..."

Description

Keywords: DCM, DCM_ADV

Urgency: Standard

General Description:
When instantiating a DCM in a Virtex-4 design, I receive the following error:

"Warning:XST:1902 - Value <-255 to 255> for attribute PHASE_SHIFT of instance <inst_name> in unit <unit_name> is not supported.
Instance <inst_name> in unit <unit_name> of type DCM has been replaced by DCM_ADV"

The phase shift value is within the valid range (-255 to 255). Why does this occur?

Solution

This warning can be safely ignored. This is a problem with the device retargeting algorithm in XST. The warning can be avoided by instantiating a DCM_ADV instead of a DCM.

This issue will be fixed in ISE 8.1i.
AR# 21525
Date Created 09/04/2007
Last Updated 01/08/2009
Status Archive
Type General Article