|
CD54AC191 Datasheet, PDF (9/10 Pages) Texas Instruments – Presettable Synchronous 4-Bit Binary Up/Down Counter | |||
|
◁ |
CD54AC191, CD54ACT191
LOAD
P0
PRESET P1
INPUTS P2
P3
CLOCK
DOWN/UP
ENABLE
Q0
Q1
Q2
Q3
TERMINAL COUNT
RIPPLE CLOCK
H
L
H
H
L
L
H
H
L
H
L
13 14 15 0 1 2
H
L
2 2 1 0 15 14 13
COUNT UP INHIBIT
LOAD
COUNT DOWN
Sequence:
1. Load (preset) to binary thirteen.
2. Count up to fourteen, ï¬fteen, zero, one, and two.
3. Inhibit.
4. Count down to one, zero, ï¬fteen, fourteen, and thirteen.
FIGURE 10. CD54AC191 DECODE COUNTERS TYPICAL LOAD, COUNT, AND INHIBIT SEQUENCES
DIRECTION
CONTROL
ENABLE
CLOCK
U/D
CE
CP TC
U/D
CE
CP TC
U/D
CE
CP TC
FIGURE 11. SYNCHRONOUS N-STAGE COUNTER WITH PARALLEL GATED TC/RC
DIRECTION
CONTROL
ENABLE
CLOCK
U/D RC
CE
CP
U/D RC
CE
CP
U/D RC
CE
CP
FIGURE 12. SYNCHRONOUS N-STAGE COUNTER USING RIPPLE TC/RC
9
|
▷ |