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AR# 17635

3.1 System Generator for DSP - Why does the black box show the wrong output type of "double" when it is specified in the "_congif.m" file?

Description

Key words: Black box, no input port, Output type, simulation

Urgency: Standard

Problem Description:
Why does the black box show the wrong output type of "double" when it is specified in the "_congif.m" file?

Example:

A black box added to a System Generator design shows the output type as "double" rather than UFix_30_0 (which is specified in the ".._config.m" file).

Even trying to use the convert blocks fails.

In the end, the "double" data type causes an error (i.e., "--- Width of Input Type is insufficient for specified bit-slice range") because it is driving a slice block that is expecting fixed point data types.

Solution

This is identified as a bug to be fixed in SysGen v6.1.

Such a problem usually stems from not having input ports (other than CLK and CE) in the black box. The work-around is to add an input port to the black box (i.e., a RESET port). This allows SysGen to correctly analyze the black box.
AR# 17635
Date Created 07/17/2003
Last Updated 06/24/2004
Status Archive
Type General Article