Model 5340A
Installation and Remote Programming
2
-
28.
Let’s look at the timing of the transition to the non
-
assertive state for these lines. DAV
may be driven high by the TALKERS after
it
recognizes that DAC
is
high. RFD may be set low as
soon
as
the LISTENER recognizes
that
DAV has been set low.
The
5340A requires RFD to be set
low no later than 50 nsec after the LISTENER sets DAC high. When the
5340A
is
a
listener
it
drives RFD low
at
the same time it sets DAC high.
The timing of DAC
is
similar to RFD, i.e.,
it
may go low
as
soon
as
DAV
is
high and
it
must be low no later than 50 nsec after RFD
is
driven
high. The 50 nsec permits a controller, when
working with only one 5340A on the bus, to
generate either DAC or RFD and invert
it
to get the other.
2
-
29.
Addressing the 534044
2
-
30. Before a 5340A can send output data or accept program information
it
MUST be addressed
to TALK or LISTEN. The method used to address it depends on the rear panel switch marked
TALK ALWAYS
-
ADDRESSABLE (See Figure 2
-
2). When in the TALK ALWAYS position, the
5340A is addressed
to
TALK
-
it outputs ONLY. It operates according to the front panel controls
and outputs each measurement. This position
is
intended for operation where there is no con
-
troller, e.g., with a digital recorder. When the rear panel switch
is
set to ADDRESSABLE, the
5340A can either be:
a.
Sent program information by
a
controller and the measured results are observed
visually, or
Both program and output information are passed on the
bus
managed by
a
controller.
b.
2
-
31.
Addresses are communicated on the data lines. When the controller sets ATN low, all
5340A’s interpret the information on data lines, DIOl through D105
as
an address. During this
time, the signal levels on D106 and
DI07, designate whether the addressed 5340A is to com
-
municate as
a
TALKER or
a
LISTENER.
D D D D
D D D
I
I
I I
I I I
0 0 0
0
0
0
0
7
6
5
4
3
2
1
1
0
A5 A4
A3
A2
A1
-
0
1
A5
A4
A3
A2
A1
-
0
0
X
X
X
X
x-
1
1
X X
X X
X
TALK ADDRESS*
LISTEN ADDRESS*
Ignored by
5340A
when
ATN
is
low
A,
-
Address switches on rear panel
X
-
Don’t care
*
-
The clear address characters
(11111)
not allowed.
I
2
-
32. The thirty
-
one
(31)
possible LISTEN and TALK address characters and their signal levels
are shown in Tables 2
-
2 and 2
-
3. A unique character is selected for each 5340A with the five
(5)
slide switches on the rear panel marked ADDRESS (A5, A4, A3, A2, A1) (see Figure 2-2). These
switches may be set to
ei4her
0
or
1
(0
represents
a
high level and
1
a
low level).
2
-
33. Two characters are yeserved for the special function of clearing or removing a 5340A from
the active
state
of
an addredsed TALKER or LISTENER. The 534014 is cleared
as
a
LISTENER
if
it is sent an ASCII
“?”
dhile ATN is low. The 5340A
is
cleared
as
a
TALKER if another instru-
ment
is
addressed to qALK or
it
is
sent an ASCII
‘‘-”
(underscore) while ATN
is
low.
It
is
cleared as either
a
TALKER or LISTENER when IFC
is
low.
,’
i
2
-
7
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