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AR# 20950

Spartan-3/E - Can I leave HSWAP_EN unconnected? Does HSWAP_EN have an internal pull-up prior to configuration?

Description

Can I leave HSWAP_EN unconnected if it is not used? Does HSWAP_EN have an internal pull-up prior to configuration?

Solution

HSWAP_EN has an internal pull-up prior to configuration. The strength of the pull-up is defined by Irpu in the device data sheet. For Spartan-3 this internal pull-up is strong enough to hold the pin High so no external resistor is needed. For Spartan-3E the internal pull-up is weaker so extra precaution can be taken by adding a stronger external pull-up to ensure a logic level High.

For more information on hot swapping Spartan-3 devices, see (Xilinx Answer 19777).

The DC and Switching Characteristic datasheet for Spartan-3 can be found at:

http://www.support.xilinx.com/xlnx/xweb/xil_publications_display.jsp?sGlobalNavPick=&sSecondaryNavPick=&category=-1209725&iLanguageID=1

The DC and Switching Characteristic datasheet for Spartan-3E can be found at:

http://www.support.xilinx.com/xlnx/xweb/xil_publications_display.jsp?sGlobalNavPick=&sSecondaryNavPick=&category=-1211389&iLanguageID=1

AR# 20950
Date Created 09/04/2007
Last Updated 12/15/2012
Status Active
Type General Article