74LCX32646 Datasheet, PDF (6/11 Pages) Fairchild Semiconductor – Low Voltage 32-Bit Transceiver/Register with 5V Tolerant Inputs and Outputs (Preliminary)

Preliminary
Functional Description
In the transceiver mode, data present at the HIGH imped-
ance port may be stored in either the A or B register or
both. The select (SAB_n, SBA_n) controls can multiplex
stored and real-time. The examples shown below demon-
strate the four fundamental bus-management functions
that can be performed for data I/O 1A and 1B: 0 - 7.
The direction control (DIR_n) determines which bus will
receive data when OE_n is LOW. In the isolation mode (OE_n
HIGH), A data may be stored in one register and/or B data
may be stored in the other register. When an output func-
tion is disabled, the input function is still enabled and may
be used to store and transmit data. Only one of the two
busses, A or B, may be driven at a time.
Real-Time Transfer
Bus B to Bus A
Real-Time Transfer
Bus A to Bus B
OE₁ DIR₁ CPAB₁ CPBA₁ SAB₁ SBA₁
L
L
X
X
X
L
Transfer Storage
Data to A or B
OE₁ DIR₁ CPAB₁ CPBA₁ SAB₁ SBA₁
L
H
X
X
L
X
Storage
OE₁ DIR₁ CPAB₁ CPBA₁ SAB₁ SBA₁
L
L
X H or L X
H
L
H H or L X
H
X
OE₁
L
L
H
H
DIR₁
H
X
X
X
CPAB₁ CPBA₁ SAB₁
X
L
 X
X
X
X
 X
X
SBA₁
X
L
X
X
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