74lvth652 Fairchild Semiconductor, 74lvth652 Datasheet - Page 3

• Manufacturer Part Number: 74lvth652
• Description: Low Voltage Octal Transceiver/register With 3-state Outputs
• Manufacturer: Fairchild Semiconductor

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, SBA) controls can multiplex stored and
real-time.
The examples below demonstrate the four fundamental
bus-management functions that can be performed with the
LVTH652.
OEAB
OEAB
X
L
L
L
OEBA
OEBA
H
X
H
L
Real-Time Transfer
Bus B to Bus A
CPAB
CPAB


X
X
Storage
CPBA
CPBA


X
X
SAB
SAB
X
X
X
X
SBA
SBA
X
X
X
L
3
Data on the A or B data bus, or both can be stored in the
internal D-type flip-flop by LOW-to-HIGH transitions at the
appropriate Clock Inputs (CPAB, CPBA) regardless of the
Select or Output Enable Inputs. When SAB and SBA are in
the real time transfer mode, it is also possible to store data
without using the internal D-type flip-flops by simulta-
neously enabling OEAB and OEBA. In this configuration
each Output reinforces its Input. Thus when all other data
sources to the two sets of bus lines are in a HIGH imped-
ance state, each set of bus lines will remain at its last state.
OEAB
OEAB
H
H
OEBA
OEBA
H
L
Real-Time Transfer
Transfer Storage
Bus A to Bus B
Data to A or B
CPAB
CPAB
H or L
X
CPBA
CPBA
H or L
X
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SAB
SAB
H
L
SBA
SBA
X
H