HP 5384A Service Manual

HP 5384A and HP 5385A
Service
I I
L--.J
TRANSPARENT
LATCHES
r-- -,
I I
-fcm r
I I
L • •• .J
EDGE- TRIGGERED
r---,
I I
~ Cm1~
I I
L --- .J
PULSE-TRIGGERED
r---1
I 1
--fcm•r
I I
L-- ·-'
DATA-LOCK-OUT
B
1
1
D
1/2 SN7475
1/2 SN7474
fl
12/SN74LS107
1/2 SN74107
1/2 SN74111
Figure 8-24. Four Types of Bistable Circuits
8-127. Transparent latches have a level-operated
control input. The D input is active as long asthe C
input is at its internal 1 state. The outputs respond
immediately. Edge-triggered elements accept data
from D, J, K, R, or S inputs on the active transition of C.
Pulse-triggered elements require the setup of data
before the start of the control pulse; the C input is
considered static since the data must be maintained as
long as Cis at its 1 state. The output is postponed until
C returns to its 0 state. The data-lock-out element is
similar to the pulse-triggered version except that the
C input is considered dynamic in that shortly after C
goes through its active transition, the data inputs are
disabled and data does not have to be held. However,
the output is still postponed until the C input returns
to its initial external level.
8-128. Notice that synchronous inputs can be readily
recognized by their dependency (10, 1J, 1K, 15, 1R)
compared to the asynchronous inputs (S,R), which
are not dependent on the C inputs.
8-129. Coders
8-130. The general symbol for a coder or code
converter is shown in Figure 8-25. X and Y may be
replaced by appropriate indications of the code used
to represent the information at the inputs and at the
outputs, respectively.
8-18
Figure 8-25. Coder General Symbol
8-131. Indication of code conversion is based on the
following rule:
Depending on the input code, the internal logic
states of the inputs determine an internal value.
This value is reproduced by the internal logic states
of the outputs, depending on the output code.
8-132. The indication of the relationships between
the internal logic states of the inputs and the internal
value is accomplished by:
a. labeling the inputs with numbers. In this case
the internal value equals the sum of the weights
associated with those inputs that stand at their internal
1 state, or by;
b. Replacing X by an appropriate indication of the
input code and labeling the inputs with characters
that refer to this code.
8-133. The relationships between the internal value
and the internal logic states of the outputs are indi-
cated by:
a. labeling each output with a list of numbers
representing those internal values that lead to the
internal1 state of that output. These numbers shall be
separated by solidi (slant:/) as in Figure 8-26. This
labeling may also be applied when Y is replaced by a
letter denoting a type of dependency (see paragraphs
8-135 and 8-136). If a continuous range of internal
values produces the internal1 state of an output, this
can be indicated by two numbers that are inclusively
the beginning and the end of the range, with these
two numbers separated by three dots, e.g., 4 ... 9 =
4/5/6/7/8/9, or by;
TRUTH TABLE
INPUTS OUTPUTS
c
b
a
g
I
e
d
0
0 0
0
0 0
0
XIV
0
0
1 0
0
0
1
a-
1 1/4
~d
0 1 0 0 0 1 0
b-
2
2/3
t--e
0 1
1
0 1 1 0
C-
4 3/4
t--1
7
t--9
1
0 0 0 1 0
1
1
0
1
a·
0
0 0
1
1
0
0
0 0
0
1
1 1
1
0
0 0
Figure 8-26. An X-Y Code Converter
•
•
•

HP 5384A Specifications

General

Brand	HP
Model	5384A
Category	Cash Counter
Language	English