UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 12770

5.1i XST - 3-state control logic is not replicated for each IOB

Description

Keywords: XST, 3, three, tri, state, tristate, VHDL, IOB

Urgency: Standard

General Description:
When I synthesize a design with 3-state control, XST does not replicate the logic for each IOB; one 3-state control logic is created for a bus of bidirectional ports.

Solution

To avoid this problem, change the synthesis pack option as follows:

1. Right-click on Synthesize -> Properties.
2. Choose "Xilinx-Specific Options".
3. Select "Pack Registers into IOBs".
4. Change the selection from "Auto" to "Yes".
AR# 12770
Date Created 10/05/2001
Last Updated 10/20/2005
Status Archive
Type General Article