Philips Semiconductors
Octal bus transceiver/register, inverting (3-State)
Product specification
74ABT648
FUNCTION TABLE
INPUTS
DATA I/O
OE
DIR
CPAB CPBA SAB SBA
An
Bn
OPERATING MODE
X
X
↑
X
X
X
Input
Unspecified
output*
Store A, B unspecified
X
X
X
↑
X
X
Unspecified
output*
Input
Store B, A unspecified
H
H
X
↑
↑
X
X
X
H or L H or L
X
X
Input
Input
Store A and B data
Isolation, hold storage
L
L
L
L
X
X
X
X
L
H or L
X
H
Output
Input
Real time B data to A bus
Stored B data to A bus
L
L
H
X
X
H
H or L
X
L
X
H
X
Input
Output
Real time A data to B bus
Stored A data to B bus
H = High voltage level
L = Low voltage level
X = Don’t care
↑ = Low-to-High clock transition
*
The data output function may be enabled or disabled by various signals at the OE input. Data input functions are always enabled, i.e.,
data at the bus pins will be stored on every Low-to-High transition of the clock.
LOGIC DIAGRAM
OE 21
DIR 3
23
CPBA
22
SBA
1
CPAB
2
SAB
4
A0
1of 8 Channels
1D
C1
Q
1D
C1
Q
20
B0
5
A1
6
A2
7
A3
8
A4
A5 9
10
A6
A7 11
1998 Jun 08
DETAIL A X 7
4
19
B1
18
B2
17
B3
16
B4
15
B5
14
B6
13
B7
SA00081