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8286/8287
8286
r-------,
8287
r-------,
I I
I
L-_~~
I I
~
I
........
! L I
I
Figure
3.
Logic Diagrams
Table
1.
Pin Description
Pin
~e~crlpllon
T
TRANSMIT (Input). T is
an
input control signal ul!ed
to
control the direction
of
the transceivers.
When
HIGH,
it
configures the transceiver's Bo-B7 as outputs with ArrA7 as inputs. T LOW con·
figures Ao-A7 as the outputs with Bo-B7 serVing as the Inputs.
OE
OUTPUT ENABLE (Input).
OE
Is
an
input control signal used
to
enable the appropriate output
driver
(as
selected by
T)
onto
its
respective bus. This signal
Is
active
LOW.
Ao-A7
LOCAL
BUS
DATA PINS (Input/Output). These pins serve
to
either present data
to
or accept data
from the processor's
local bus depending upon the state
of
the T pin.
~-!!z
(8286)
SYSTEM
BUS
DATA PINS (Input/Output). These pins serve
to
either present data
to
or accept
Bo-
B7
(8287)
data from the system bus depending upon the state
of
the T pin.
FUNCTIONAL DESCRIPTION
The
8286
and 8287 transceivers are 8·bit transceivers with high impedance outputs. With T active HIGH and
OE
active
LOW, data at
~he
Ao-A7 pins
is
driven
onto
the Bo-B7 pins. With T inactive
LOW
and
OE
active LOW, data at the Bo-B7
pins is driven
onto
the Ao-A7 pins. No output low glitchlng will
occur
whenever the transceivers are entering
or
leaving
the high impedance state.
8-49
AFN
01506A