MC74AC646_15 Datasheet, PDF (3/10 Pages) ON Semiconductor – Octal Transceiver/Register with 3-State Outputs

MC74AC646, MC74ACT646
FUNCTION TABLE
Inputs
G
DIR CAB CBA SAB SBA
Data I/O*
A₀−A₇
B₀−B₇
Operation or Function
H
X
H or L H or L
X
X
H
X
X
X
Input
Input
Isolation
Store A and B Data
L
L
L
X
X
X
L
L
X
X
X
H
Output
Input
Real Time B Data to A Bus
Stored B Data to A Bus
L
H
X
X
L
X
L
H
H or L
X
H
X
Input
Output
Real Time A Data to B Bus
Stored A Data to B Bus
*The data output functions may be enabled or disabled by various signals at the G and DIR inputs. Data input functions are always enabled;
i.e., data at the bus pins will be stored on every LOW−to−HIGH transition of the appropriate clock inputs.
NOTE: H = HIGH Voltage Level; L = LOW Voltage Level; X = Immaterial; = LOW−to−HIGH Transition
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