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AR# 11531

3.1i Virtex-II Speed Files - Incorrect delay on differential buffers

Description

Keywords: time_sim, edn, LVDS, IBUFDS

Urgency: Standard

General Description:
The speed files for the Virtex-II are not reporting symmetrical delays for both pairs of differential input pins. (This information is reported in the time_sim file.)

An instance of this behavior is illustrated in the following snippet from a time_sim.edn. (Note that "portInstance IB" has no values.):

(instance (rename &_I10 "$I10")
viewRef view_1 (cellRef x_ibufds (libraryRef SIMPRIMS)))
(portInstance O
property RISE (integer 697)(unit TIME) (owner "Xilinx"))
(property FALL (integer 697)(unit TIME) (owner "Xilinx")))
(portInstance IB)
(portInstance I
(property RISE (integer 685)(unit TIME) (owner "Xilinx"))
(property FALL (integer 685)(unit TIME) (owner "Xilinx"))))

Solution

This problem is fixed in the latest 3.1i Service Pack, available at:
http://support.xilinx.com/support/techsup/sw_updates.
The first service pack containing the fix is 3.1i Service Pack 8.
AR# 11531
Date Created 05/03/2001
Last Updated 08/26/2002
Status Archive
Type General Article