93L00 Datasheet, PDF (4/8 Pages) National Semiconductor (TI) – 4-Bit Universal Shift Register

Functional Description
The Logic Diagrams and Truth Table indicate the functional
characteristics of the 93L00 4-bit shift register The device is
useful in a wide variety of shifting counting and storage
applications It performs serial parallel serial-to-parallel or
parallel-to-serial data transfers
The 93L00 has two primary modes of operation shift right
x (Q0 Q1) and parallel load which are controlled by the
state of the Parallel Enable (PE) input When the PE input is
HIGH serial data enters the first flip-flop Q0 via the J and K
inputs and is shifted one bit in the direction
x x x Q0 Q1 Q2 Q3 following each LOW-to-HIGH
clock transition The JK inputs provide the flexibility of the
JK type input for special applications and the simple D-type
input for general applications by tying the two pins together
Truth Table
Operating
Inputs (MR e H)
Mode
PE
J
K
P0
P1
H
L
L
X
X
Shift Mode
H
L
H
X
X
H
H
L
X
X
H
H
H
X
X
Parallel
L
X
X
L
L
Entry Mode
L
X
X
H
H
t_na₁ e Indicates state after next LOW-to-HIGH clock transition
H e HIGH Voltage Level
L e LOW Voltage Level
X e Immaterial
When the PE input is LOW the 93L00 appears as four com-
mon clocked D flip-flops The data on the parallel inputs
P0 – P3 is transferred to the respective Q0 – Q3 outputs fol-
lowing the LOW-to-HIGH clock transition Shift left opera-
x tion (Q3 Q2) can be achieved by tying the Qn outputs to
the Pnb1 inputs and holding the PE input LOW
All serial and parallel data transfers are synchronous occur-
ing after each LOW-to-HIGH clock transition Since the
93L00 utilizes edge triggering there is no restriction on the
activity of the J K Pn and PE inputs for logic operation ex-
cept for the setup and release time requirements A LOW on
the asynchronous Master Reset (MR) input sets all Q out-
puts LOW independent of any other input condition
Outputs t_na₁
P2
P3
Q0
Q1
Q2
Q3
Q3
X
X
L
Q0
Q1
Q2
Q2
X
X
Q0
Q0
Q1
Q2
Q2
X
X
Q0
Q0
Q1
Q2
Q2
X
X
H
Q0
Q1
Q2
Q2
L
L
L
L
L
L
H
H
H
H
H
H
H
L
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