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AR# 9401

3.1i XST - XST selects one-hot encoding for state machines, regardless of what encoding was chosen.


Keywords: WebPACK, encoding, scheme, XST, ISE, one-hot, Project, Navigator

Urgency: Hot

General Description:
I have selected Johnson encoding for my state machine when synthesizing with XST. After fitting the design, it appears as if the software has ignored the request and is using one-hot encoding instead.

From the report:

---- Other Options
c : Johnson
| Encoding | automatic
Selecting encoding for FSM_0 ...
Encoding for FSM_0 is One-Hot, flip-flop = D

The same thing happens if other encoding schemes are selected, and the problem is apparently not specific to any device family.


This problem is fixed in the latest 3.1i Service Pack, available at:
The first service pack containing the fix is 3.1i Service Pack 6.
AR# 9401
Date Created 06/01/2000
Last Updated 08/20/2002
Status Archive
Type General Article