HP 3468A - Page 46

|
.
(Cont’d)
When
the
3468A
was
placed
in
the
Single
Trigger
mode,
it
took
one
reading
and
stored
it
internally.
When
the
first
INSTAT
command
was
executed,
the
calculator
display
showed
a
”1”.
This
is
because
bit
O
of
the
3468A
Status
Register
was
set
due
to
the
measurement
data
being
ready.
When
Flag
OO
was
tested
(FS?
00)
it
was
set
and
the
calculator
displayed
“
YES”.
With
the
IND
command,
the
measurement
data
was
sent
to
the
calculator
and,
since
the
3468A
was
in
the
Single
Trigger
mode,
no
new
measurements
were
taken.
Therefore,
no
new
data
became
available
and
bit
O
in
the
Status
Register
is
clear.
This
is
evident
by
the
second
INSTAT
command
returning
a
“O”
and
the
test
for
Flag
00
being
“NO”.
The
FS?
or
FC?
tests
may
be
used
in
programs
to
branch
to
subroutines
if
data
is
or
is
not
ready.
Example
2.
Front
Panel
SRO
The
front
Panel
SRO
key
on
the
3468A
can
be
used
to
signal
the
calculator
to,
for
example,
begin
a
data
manipulation
subroutine.
As
in
the
previous
example,
we'll
use
the
INSTAT
and
Flag
test
commands,
except
that
we
will
test
Flag
04.
Flag
04
represents
bit
4
in
the
Status
Register.
Before
beginning
this
example,
make
sure
that
the
3468A
is
set
to
the
internal
trigger
mode.
|
Keystrokes
HP
41
Display
Comments
this indicates Data Ready.
ALPHA]
INSTAT
[ALPHA]
1.0000
As
in
the
previous
example
FS?}
04
NO
Flag
04
(bit
4)
is
not
set.
Now,
press
the
3468A
front
panel
SRO
key.
ALPHA]
INSTAT
[ALPHA]
17.0000
_
The
display
shows
17
for
bits
4
(value
16)
and
1
(value
1).
(0)
[Fs?7]
04
YES
Flag
04
(bit
4)
is
set
because
the
SRO
key
was
pressed.
After
the
3468A
front
panel
SRO
key
was
pressed,
bit
4
in
the
Status
Register
was
set.
Consequently,
when
the
INSTAT
command
was
executed,
Flag
04
was
set.
The
SRO
annunciator
did
not
come
on
and
the
SRQ
message
was
not
sent
because
the
SRO
mask
was
not
set
for
this
bit.
41