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AR# 15437

7.1i CPLD CoolRunner-II, Pin2UCF - CONFIG VREF statements are not written into the User Constraints File (UCF)

Description

General Description: 

In CoolRunner-II devices, VREF pins may be configured on any user I/O pin. If I do not specify these VREF pins, the CPLD Fitter will create them for me. However, when the "Lock Pins" process executes, these VREF statements are not written into the User Constraints File (UCF).

Solution

After implementing the design, inspect the GYD file (designname.gyd), at the bottom of the report, a section lists all VREFs used by the design. 

 

They will have a format similar to the following: 

 

CONFIG VREF = P23; 

 

Copy and paste all CONFIG VREF statements into your UCF. Re-implement and verify that the statements are used by inspecting the pin-out section at the bottom of the fitter report.

AR# 15437
Date Created 09/03/2007
Last Updated 05/14/2014
Status Archive
Type General Article