Hardware Reference
In-Depth Information
6.4.3.2
2-Coupling Static Faults
2-coupling static FFMs are faults described by FPs involving two
f-cells
(
j
f
j D
2)
and sensitized by the application of at most a single memory operation (m
1). In
this condition, one of the two
f-cells
(usually denoted by the generic address
v
)isthe
victim cell where the effect of the faulty behavior manifests, while the second cell
(usually denoted by the generic address a) is the aggressor cell, responsible with the
victim for producing the faulty behavior. With this distinction three classes of
SOSs
can be generated:
1.
No cell accessed: the state of the cells sensitizes the fault.
2.
Only the aggressor cell is accessed.
3.
Only the victim cell is accessed: the aggressor contributes to the fault simply
with its initial state.
Starting with this classification it is possible to enumerate the space of 2-coupling
FPs of Table
6.2
composed of 36 different FPs. Only those combinations of opera-
tions that actually represent a faulty behavior have been considered.
As for the single-cell static FFMs, this set of FPs can be grouped to define a set
of seven well established and characterized FFMs:
1.
State Coupling Fault (CFst)
: the victim cell is forced into a given logic state
when the aggressor cell is in a given state, without performing any operation.
As for the state fault, this FFM is special, as no operation is required to sensi-
tize the fault. Four types of state coupling faults exist, defined as CF
st.xy/
D
f
<x
a
y
v
= y
v
=
>
g
,wherex; y
2 f
0; 1
g
. This covers FP
1
,FP
2
,FP
3
,andFP
4
.
Tabl e 6. 2
2-coupling FP space
#
FP
#
FP
<0
a
0
v
=1
v
= >
<0
a
0
v
;
w
1
=0
v
= >
1
19
<0
a
1
v
=0
v
= >
<1
a
0
v
;
w
1
=0
v
= >
2
20
<1
a
0
v
=1
v
= >
<0
a
1
v
;
w
0
=1
v
= >
3
21
<1
a
1
v
=0
v
= >
<1
a
1
v
;
w
0
=1
v
= >
4
22
<0
a
0
v
;
w
0
=1
v
= >
<0
a
1
v
;
w
1
=0
v
= >
5
23
<1
a
1
v
;
w
1
=0
v
= >
<0
a
1
v
;
w
0
=0
v
= >
6
24
<0
a
0
v
;
w
1
=1
v
= >
<0
a
0
v
;r
0
=0
v
=1
v
7
25
>
<1
a
0
v
;r
0
=0
v
=1
v
8
<0
a
1
v
;
w
1
=0
v
= >
26
>
<1
a
0
v
;
w
0
=1
v
= >
<0
a
0
v
;r
0
=1
v
=0
v
9
27
>
<1
a
1
v
;
w
0
=0
v
= >
<1
a
0
v
;r
0
=1
v
=0
v
10
28
>
<1
a
0
v
;
w
1
=1
v
= >
<0
a
0
v
;r
0
=1
v
=1
v
>
11
29
<1
a
1
v
;
w
1
=0
v
= >
<1
a
0
v
;r
0
=1
v
=1
v
>
12
30
<0
a
0
v
;r
0
=1
v
= >
<0
a
1
v
;r
1
=0
v
=0
v
13
31
>
<0
a
1
v
;r
0
=0
v
= >
<1
a
1
v
;r
1
=0
v
=0
v
14
32
>
<1
a
0
v
;r
1
=1
v
= >
<0
a
1
v
;r
1
=0
v
=1
v
15
33
>
<1
a
1
v
;r
1
=0
v
= >
<1
a
1
v
;r
1
=0
v
=1
v
16
34
>
<0
a
0
v
;
w
0
=1
v
= >
<0
a
1
v
;r
1
=1
v
=0
v
17
35
>
<1
a
0
v
;
w
0
=1
v
= >
<1
a
1
v
;r
1
=1
v
=0
v
18
36
>
