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Table
5.1
-
Control Logie Levels by Function
Measurement
Control Line
Function:
Q0
Q1
Q2
Q3
Q4
FREQ A
1
1
0
1
0
PERIOD A
1
1
0
1
0
FREQ
B
1
0
0
1
0
PERIOD
B
1
0
0
1
0
FREQ C
1
1
0
1
0
T.I.
A-*"B
0
0
1
1
0
T.I.
B-^A
0
0
0
1
0
TOTAL
A
by
B
1
0
0
1
1
TOTAL
B
by
A
1
0
1
1
1
RATIO
C/B
1
1
0
1
1
RATIO
A/B
1
0
1
1
1
Special
Function
72
1
1
1
0
1
Special
Function
73
1
1
1
0
0
Special
Function
74
1
1
1
0
1
Special
Function
75
1
1
1
0
0
NOTES:
a.
The
FREQ
B,
PERIOD
3,
TOTAL
B
by A, and TJ. B-*-A
functions are
obtained
using
Special
Function
21.
b.
Special Functions
72 to 75
can
only
be used
when
CHECK
is
selected.
5.3.4
Display Block
5.
3.4.1
Functional Description
5.
3.4.1.
1
A
simplified
diagram
of the display
block
is
given
in
Figure
5.6.
The
GPIB
LEDs,
GATE
LED,
Channels
A
and
B
TRIGGER
LEDs, and
the
STANDBY LED
are held
on
or
off
by control
signals
from
other
systems.
The remainder
of the display
is
multiplexed
under
the control of
the
display drivers.
5.3.4.1.2
To
update
the
display, the
microprocessor
selects the
appropriate
display
driver using
the
MODE
1
and
MODE
2
control
lines.
A
string of nine 8-bit
words
(a
control
word and
eight data words)
is
then put onto the
bus.
Each word
is
entered
into
a
memory
within the display driver
under
the control of the
STROBE
signaL
5.
3.4.1. 3
The
display driver then sequentially puts the
data words onto
its
output
bus.
For
each data word,
the appropriate
numeric
indicator or
group
of
LEDs
is
enabled
by
a
signal
on
its
control
line.
5-10
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