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AR# 15414

5.2i XST - XST does not consider default values for instantiated components

Description

Keywords: XST, component, initial, default, value, open, instance

Urgency: Standard

General Description:
When a declared component has default values on a port and the port is not connected, XST assigns incorrect initialization values. In the following example, XST reports the outputs as "0000" instead of "0010".

component Test

port ( I : in bit_vector(0 to 3) := "0010";
O : out bit_vector(0 to 3) );
end component;

begin
UUT : Test port map (I => open, O=>PO);
end architecture ;

Solution

This problem is fixed in the latest 5.2i Service Pack available at:

http://support.xilinx.com/xlnx/xil_sw_updates_home.jsp

The first service pack containing the fix is 5.2i Service Pack 2.
AR# 15414
Date Created 08/14/2002
Last Updated 10/20/2005
Status Archive
Type General Article