HP
5384A and
HP
5385A
Service
8-65. Dependency Notation
8-66.
GENERAL
EXPLANATION.
Dependency
notation
is
the
powerful
tool
that
sets
the
I
EC
symbols
apart
from
previous systems and makes compact,
meaningful, symbols possible.
It
provides the means
of
denoting
the
relationship between inputs,
outputs,
or
inputs and outputs
without
actually
showing
all
the
elements and
interconnections
involved. The
infor-
mation
provided
by
dependency
notation
supple-
ments that
provided
by
the
qualifying
symbols
for
an
element's
function.
In
cases
where
it
is
not
evident
which
inputs must
be
considered
as
being the affecting
or
the
affected ones
(e.g.,
if
they stand in
an
AND
relationship),
the
choice
may be made
in
any
convenient
way.
8-68.
So
far,
11
types
of
dependency
have been
defined
and
10
of
these are used
in
the
Texas
Instruments data
book.
They are listed
below
in
the
order
in
which
they
are presented and are sum-
marized
in
Table 8-5.
8-67.
In the convention
for
the
dependency
notation,
use
will be made
of
the terms "affecting" and "affected".
Table 8-5.
Summary
of
Dependency
Notation
TYPE
OF
LETTER
AFFECTING
INPUT
AFFECTING
INPUT
DEPENDENCY
SYMBOL*
AT
ITS
1-STATE
AT
ITS
0-STATE
Address A Permits action (address selected)
Prevents action (address
not
selected)
Control
c
Permits action Prevents action
Prevents action
of
inputs.
0
outputs
off.
Enable
EN
Permits action V
outputs
at
external
high
impedance
no
change
in
internal
logic
state.
Other
outputs
at
internal
0 state.
AND
G
Permits action Imposes 0 state
Mode
M Permits action (mode selected) Prevents action
(mode
not
selected)
Negate
(X-OR)
N
Complements
state
No
effect.
RESET
R
Affected
output
reacts
as
it
No
effect
would
to
S =
0,
R = 1
SET
s
Affected
output
reacts
as
it
No
effect
would
to
S = 1, R = 0
OR
v Imposes 1 state Permits action
Transmission X
Bidirectionally
connected
input
Input
to
output
bidirectionally
to
output
not
connected
Interconnection
z Imposes 1 state Imposes 0 state
*These letter symbols
appear
at
the
AFFECTING
input
(or
output)
and
are
followed by a
number.
Each
input
(or
output)
AFFECTED
by
that
input
is
labeled
with
that
same
number.
When
the
labels
EN,
R,
and
S
appear
at inputs
without
the
following
numbers,
the
descriptions
above
do
not
apply. The action of
these
inputs
is
described
under
"Symbols Inside
the
Outline".
8-10
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