dm74als652 Fairchild Semiconductor, dm74als652 Datasheet - Page 2

• Manufacturer Part Number: dm74als652
• Description: Dm74als652 Octal 3-state Bus Transceiver And Register
• Manufacturer: Fairchild Semiconductor

www.fairchildsemi.com
Function Table
H
L
X
H/L
Note 1: The data output functions may be enabled or disabled by various signals at the G and DIR inputs. Data input functions are always enabled,
Note 2: Select control
Logic Diagram
LOW Logic Level
Positive-going edge of pulse
HIGH Logic Level
Don’t Care (Either LOW or HIGH Logic Levels, including transitions)
GAB
Either LOW or HIGH Logic Level excluding transitions
X
H
H
H
H
L
L
L
L
L
L
Select control
i.e., data at the bus pins will be stored on every LOW-to-HIGH transition on the clock inputs.
GBA
H
H
H
H
H
H
X
L
L
L
L
L; clocks can occur simultaneously
H; clocks must be staggered in order to load both registers.
H or L
CAB
H/L
H/L
X
X
X
Inputs
H or L
CBA
H/L
H/L
H/L
X
X
(Note 2)
SAB
X
X
X
X
X
X
X
X
X
H
L
(Note 2)
SBA
X
X
X
X
H
X
X
X
X
H
L
Not Specified
2
A1 thru A8
Output
Output
Output
Output
Input
Input
Input
Input
Input
Input
Data I/O (Note 1)
Not Specified Store A, Hold B
B1 thru B8
Output
Output
Output
Output
Input
Input
Input
Input
Input
Input
Store B, Hold A
Store A and B Data
Isolation, Hold Storage
Real-Time B Data to A Bus
Stored B Data to A Bus
Real-Time A Data to B Bus
Stored A Data to B Bus
Store A in both Registers
Store B in both Registers
Stored A Data to B Bus and
Stored B Data to A Bus
Operation or Function