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AR# 33274

11.3 PlanAhead - Default I/O standards are not written out into the UCF

Description

Keywords : LVCMOS25, LVDS_25

I imported a CSV file into the PlanAhead tool and then wrote out the ports into the ".ucf", but when I look in the UCF file, none of the LVDS_25 or the LVCMOS25 I/O standards have been written into the ".ucf". Why is this occurring?

Solution

This is the expected behavior for PlanAhead software; it will not write out the default I/O standards.

The default I/O standard for a single-ended standard is LVCMOS25, and for a differential standard it is LVDS_25. If you have any other standards other than the defaults, PlanAhead software writes those out to the ".ucf".
AR# 33274
Date Created 08/18/2009
Last Updated 09/16/2009
Status Active
Type General Article