Answers Database

Foundation State Editor F1.3/F1.4, XABEL: One-hot state machine is created "Cold"


Record #3151

Product Family:  Software

Product Line:  Aldec

Problem Title:
Foundation State Editor F1.3/F1.4, XABEL:  One-hot state machine is
created "Cold"



Problem Description:
Keywords:  abel, one-hot, fsm, initialize

Urgency:  Standard

General Description:

When creating a one-hot state machine through the Foundation
State Editor with Abel as the synthesis language, the state
machine produced will be "cold", ie, it will never move from
the "000" state.


Solution 1:

This problem is caused by the fact that the Abel code is
produced with all state registers initializing to 0.  This
means that the state machine powers up to all 0's, and
therefore is not in any state in the one-hot encoded state
machine.

The workaround is to manually edit the ABEL code such that the
code will initialize to the initial-state.  To do this, add
the following line to the Equations section of the Abel code:

<INIT_STATE>.AP = 0;

where <INIT_STATE> is the desired initial state.

This will force this particular state register to be a "preset"
register, and therefore power-up to '1', and therefore the
one-hot state machine will be in this state to begin with.



End of Record #3151