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!
  1. Xilinx - Adaptable. Intelligent.
  2. Support
  3. AR# 2509: Foundation XVHDL - Cannot instantiate the XBlox TRISTATE component without pullups

AR# 2509

Foundation XVHDL - Cannot instantiate the XBlox TRISTATE component without pullups

Description

Keywords: xblox, metamor, xvhdl, tristate, pullup

Urgency: Standard

General Description:
When instantiating an XBlox TRISTATE component within a Foundation XVHDL design, the synthesiser will complain if you do not pass both the ENCODING and FLOAT_VAL parameters. The only values allowed for the FLOAT_VAL parameter are PULLUP and PULLUP_D. This means that internal tristates must have pullups on the outputs. However, the documentation says that this should be an 'optional' parameter.

Solution

Open the "Xblox.vhd" file in the "C:\active\VHDL\VHDL\Vhdl_lib" directory and change the following line :

component TRISTATE is
generic (FLOAT_VAL : string;
ENCODING : string := "");

to

component TRISTATE is
generic (FLOAT_VAL : string :="";
ENCODING : string := "");

by inserting the extra :=""

This will allow you to omit the FLOAT_VAL parameter in your VHDL source code. The result will be internal tristates with
no pullups.
AR# 2509
Date 12/06/2005
Status Archive
Type General Article
Page Bookmarked