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AR# 14936

7.1i Virtex-II Pro MAP - IOBUFDS without a defined I/O standard uses incorrect default and fails with "ERROR: Pack: 1107..."

Description

General Description:

I receive a "MAP fails" with the following error. Why?

"ERROR:Pack:1107 - Unable to combine the following symbols into a single DIFFS component:

PAD symbol "inst0_IOBUFDS_IOB" (Pad Signal = inst0_IOBUFDS_IOB)

SlaveBuffer symbol "inst0_IOBUFDS_IOB.DIFFIN" (Output Signal = inst0_IOBUFDS_IOB.DIFFIN)

SlaveBuffer symbol "inst0_IOBUFDS_IOB.DIFFOUT" (Output Signal = inst0_IOBUFDS_IOB)

More than one SLAVE buffer. The current IOSTANDARD does not support bidirectional usage."

Solution

This pack error occurs because an IOBUFDS is being used, but no I/O standard is assigned to it, and an unsupported I/O standard is being selected by default. (Virtex-II Pro does not support bidirectional usage for LVDS_25.)

This problem will be fixed in design tools version 8.2i. Meanwhile, you can avoid the problem by assigning valid I/O Standards to all IOBUFDS symbols in Virtex-II Pro designs.

In general, when I/O Standards are not properly defined for all I/O components, default values are chosen by MAP. Appropriate values are not always chosen which can lead to a variety of failure modes including pack errors and I/O banking rule errors.

AR# 14936
Date Created 08/29/2007
Last Updated 12/15/2012
Status Active
Type General Article