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AR# 12003

Virtex-E/Spartan-IIE Data Sheet - How do I determine VREF pins for a specific device and package combination from a pin-out table?

Description

General Description:

How do I determine VREF pins for a specific device and package combination?

For example, in the Virtex-E pin-out table data sheet version 2.3 (http://support.xilinx.com/partinfo/ds022-4.pdf),a note regarding the pin-out for the FG680 on page 81 (Module 4 of 4) states:

1. VREF or I/O option only in the XCV1000E, 1600E, 2000E. (FG680 package!)

What is the pin when I have a V600E? Is it unused, I/O-only, or VREF-only?

(In the Spartan-IIE data sheet, this pins are listed per device/package combination.)

Solution

The bigger devices need more VREF, and the smaller ones need less. So by default, if it is not explained and the pin is designated <IO_VREF_#...>, then it is automatically I/O.

For example, examine pin AV14 in Bank 4, which is listed as IO_VREF_L144P_YY in the FG680 pin-out for "Note 1". In this case, the package file "v600Efg680.pkg" listed this I/O as "IO_L144_YY", which means it can be used as an I/O. The package file "v1000efg680" listed this I/O as "IO_VREF_4_L144P_YY", which means it can be used as either an I/O or a VREF.

The same applies to Spartan-IIE pin-outs. If it is NOT listed as "IO_VREF_#...", it is not a VREF in that package.

The best way to determine what pins are I/O is to view the package file for the specific device and package information. The package file can be obtained through one of the following methods:

1. Run "partgen -v <device_package_combination>" on a command prompt with the Xilinx software installed.

For example:

partgen -v v600efg680

The <device>.pkg file will be copied into your directory.

2. Access the package files on the web:

For Virtex-E:

http://www.xilinx.com/products/virtex/vepackages.htm

For Spartan-IIE, use the "partgen" command.

AR# 12003
Date Created 08/29/2007
Last Updated 12/15/2012
Status Active
Type General Article