December 1990 4
Philips Semiconductors Product specification
4-bit bidirectional universal shift register 74HC/HCT194
FUNCTION TABLE
Notes
1. H = HIGH voltage level
h = HIGH voltage level one set-up time prior to the LOW-to-HIGH CP transition
L = LOW voltage level
I = LOW voltage level one set-up time prior to the LOW-to-HIGH CP transition
q,d = lower case letters indicate the state of the referenced input (or output) one set-up time prior to the
LOW-to-HIGH CP transition
X = don’t care
↑ = LOW-to-HIGH CP transition
OPERATING MODES
INPUTS OUTPUTS
CP MR S
1
S
0
D
SR
D
SL
D
n
Q
0
Q
1
Q
2
Q
3
reset (clear) X L XXXXXLLLL
hold (“do nothing”) X H I I X X X q
0
q
1
q
2
q
3
shift left
↑
↑
H
H
h
h
I
I
X
X
I
h
X
X
q
1
q
1
q
2
q
2
q
3
q
3
L
H
shift right
↑
↑
H
H
I
I
h
h
I
h
X
X
X
X
L
H
q
0
q
0
q
1
q
1
q
2
q
2
parallel load ↑ HhhXXd
n
d
0
d
1
d
2
d
3
Fig.4 Functional diagram.
