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AR# 10945

3.x FPGA Express - When ports are assigned to a logic "zero" or "one", the error "NGDBuild: 397 Could not find NET <> in design" appears.

Description

Keywords: FPGA Express, ports, assign, zero, one, 0, 1

Urgency: Standard

General Description:
Using FPGA Express, I am attempting to constrain a number of ports that have been assigned to a logic "one" or "zero". During the Translate step, however, the following error appears:

"ERROR:NgdBuild:397 - Could not find NET '<>' in design '<>'. NET entry is 'NET "<>" LOC = "<>";"

Solution

FPGA Express is not inferring the proper output buffers on these ports; therefore, they can not be constrained.

To work around this problem, instantiate the proper output buffer component, then port a signal to that buffer component that has been assigned to the desired logic level:

:
:

component OBUF
port (I : in std_logic;
O : out std_logic);

signal Zero : STD_LOGIC;
signal One : STD_LOGIC;

begin

Zero <= '0';
One <= '1';

:
:

u0 : OBUF port map (I => one, O => output_port_1);
u1 : OBUF port map (I => zero, O => output_port_2);
AR# 10945
Date Created 02/07/2001
Last Updated 08/11/2003
Status Archive
Type General Article