74F779 Datasheet, PDF (3/12 Pages) NXP Semiconductors – 8-bit bidirectional binary counter 3-State

Philips Semiconductors
8-bit bidirectional binary counter (3-State)
Product specification
74F779
LOGIC SYMBOL
11
10
14
CET
15
CP
S0
S1
TC
12
9
OE
I/O0 I/O1 I/O2 I/O3 I/O4 I/O5 I/O6 I/O7
V_CC=Pin 13
GND=Pin 4
16 1 2 3 5 6 7 8
SF01260
LOGIC SYMBOL (IEEE/IEC)
CTR DIV 256
11
10
0
0
M—
LOAD
DOWN
1
3 _UP
14
HOLD
EN4
15
2 +/C5
1–
9
EN6
16
[1]
6
[2]
1
[4]
2
3
[8]
5
[16]
6
[32]
7
[64]
8
[128]
4, 5, 8 CT=256
12
4, 5, 8 CT=0
SF01261
FUNCTION TABLE
INPUTS
OPERATING MODE
S1 S0 CET OE CP
X X X H X I/O0 to I/O7 in High impedance
X X X L X Flip-flop outputs appear on I/O lines
L L X H ↑ Parallel load all flip-flops
(not LL) H X ↑ Hold (TC held High)
H L L X ↑ Count up
L H L X ↑ Count down
H = High voltage level
L = Low voltage level
X = Don’t care
↑ = Low-to-High clock transition
(not LL) = S0 and S1 should never be Low voltage level at the
same time in the hold mode only.
1989 Sep 20
3