Fundamental Operations in BALM - The Unknown Component Problem: Theory and Applications - page 150

-1 1
.names G16 G15 G9
0- 1
-0 1
.end

9.1 Extracting an Automaton from a Sequential Circuit

The operation extract aut builds the automaton corresponding to the FSM
extracted from a given sequential circuit, according to the construction introduced in
Definition 3.1.7, by which the inputs and outputs of the FSM are merged to become
the inputs of the automaton. In the example, the sequential circuit is given as a netlist
in BLIF format.

read_blif S27.blif
extract_aut S27.aut

The result is the automaton S27.aut shown in Fig. 9.1 .
The S27.blif file has 3 binary latches for a total of 8 possible states. However,
the result of extract aut indicates that only 6 states are reachable from the initial
state 000. The octagonal node at the top indicates that it is the initial state. The output
indicates that the automaton is incomplete with all 6 states being incomplete. Thus
when we complete the automaton, there will be a transition from each state to the

The automation is incomplete (6 states) and deterministic.
5 inputs 6 states 25 transitions
Inputs = { G0, G1, G2, G3, G17 }

00-01
011-1

000

-0-10

-0-10
0-1-0
00--0

0-1-1

010-1

010

110-1

0-1-1 010-0 0-1-0

10-01
111-1

0-1-1
00--1

110-1

001

0-0-1

011

0-0-0

10-01
111-1

1-0-1 1-0-1

0-0-1

010-1 1-1-1

101

1-1-1

1-0-1

1-1-1

110-1

100

1-1-1
10--1

Fig. 9.1 Graphical output of BALM showing the automaton s27.aut obtained by extraction
from the sequential circuit S27.blif