Specifications
5.2
UNIBUS
WINDOW
MODULE
5.2.1
FUNCTIONAL DESCRIPTION
The
M7452
module
is
a
standard
hei~ht
hex
size
module
used
as
an
interface
between
the
VS100
and
the
VAX11/7XX
cpu.
The
module
connects
to
the
VAX
unibus
backplane
and
recieves
its
power
from
the
VAX.
The
M7852
is
connected
to
the
VS100
b~
a 2
channel
fiber
optic
cable.
The
M7452
has
8-16
bit
re~isters
used
for
the
transfer
of
data
between
the
VS100
and
the
VAX
cpu.
The
VAX
is
allowed
to
address
the
control/status
re~isters
onl~.
The
VS100
can
address
either
the
control/status
reSisters
or
the
VAX
memory.
The
M7452
is
an
NPR
device
and
is
also
capable
of
interrupts
to
the
VAX.
The
address
ran~e
of
the
module
is
selected
b~
switches.
The
interrupt
vector
addresses
are
pro~rammable.
The
Interrupt
level
is
selected
b~
a
standard
BR
chip,
set
at
level
BR5.
The
unibus
module
is
capable
of
suPPortin~
one
(1)
VS100
communications
link
The
maximum
len~th
of
Fiber
optic
cable
that
can
used
with
the
VS100
is
300
meters.
MAINTANCE
MODE
LOOPBACK
The
M7452
module
is
provided
with
the
capability
to
perform
loopback
of
data
while
under
program
control.
This
is
accomplished
on
two
levels.
The
first
is
an
electrical
loopback
of
data
that
has
been
encoded
into
bi-phase
L
data
at
an
ECl
volta~e
level.While
in
this
mode,the
XMIT
ON
bit
should
be
dis-asserted.
this
will
prevent
data
from
bein~
transmitted
to
the
VS100displa~
processor
board.
Also,while
in
this
mode,
the
CRC
generator
ma~
be
disabled.
The
second
level
of
loopback
is
the
OPTICAL
loopback.
this
mode
reauires
that
an
optical
loopback
connector
(DEC
PT.
t
12-~y~~~-zz)
be
installed
on
the
fiber
optic
connectors.
While
in
this
mode,
the
XMIT
ON
bit
must
be
asserted,
and
the
CRC
generator
may
be
either
asserted
or
de-asserted.
The
loopback
process
is
started
by
first
settins
the
appropriate
bits
in
CSR
O,then
loadin~
the
data
to
be
looped
back
into
CSR5.
LoadinS
of
data
into
CSR5
will
initiate
the
loopback
seauence.
Data
will
be
loaded
into
CSR6.
If
interrupts
are
enabled,the
unibus
module
will
interrupt
the
host,with
the
vector
address
that
was
previously
loaded
onto
CSR7.
5.2.3
SWITCH SELECTABLE
BUS
ADDRESSES
The
base
address
of
the
M7852
is
selectable
throuSh
a
set
of
switches
located
on
the
module.
The
ran~e
of
addresses
is
760000-777760
(BASE
8)
The
numberin~
and
location
of
the
switches
is
as
~ollows:
address
bit
ON
OFF
switch
?osition
12
11
10
9
8
7
6
5
4
UNIBUS
ADDRESS
I
ON
ION,
I
ON
I
ON
I
I
ON
I
ON
I I
ON
I
760440(8)
JOFF I
IOFF I
FFE120(16)
1
2 3
4
5
6
7
8
9