Philips pm2521 - Page 133

141
74LS74
DUAL D-TYPE
FLIP FLOP
PIN
CONFIGURATION LOGIC
SYMBOL
9
8
MODE
SELECT-TRUTH
TABLE
OPERATING
MODE
inputs
outputs
^D
Rd
CP D O
Q
Asynchronous Set L
H X X
H L
Asynchronous
Reset
(Clear)
H L X X
L H
Undetermined
(c)
L
L X X
H H
Load
"1"
(Set) H
H
t
h H L
Load
"0"
(Reset) H H t 1
L H
H
=
HIGH
voltage
level steady state.
h
=
H IGH
voltage
level one setup
time prior to the LOW to
HIGH clock
transition.
L
=
LOW
voltage
level
steady
state.
I
=
LOW
voltage
level one setup time prior to
the LOW to
HIGH clock
transition.
X
=
Don't care.