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GPIB
IEEE488
MANUAL
INSTALLATION
switch
settings
dn
dn
up
up
up
up
= &HCOOOO
Refer
to Section
2 of the
IBM Technical
Reference
Manual
for
a
complete
system
memory
map layout.
The address
chosen
in
the
above
diagram
is COO00 hex which
is in the
192 Kbyte
expansion
area
after
the display
buffers.
This
is usually
a clear
area
on
most
IBM P.C.'s.
Make
a note
of
the
MEMORY
ADDRESS
and
the
BASE
ADDRESS
of
the
boards
for
initialization.
*****************et
WARNING
*******t*t****ttt*tt
NO CHECK
IS
MADE
ON THE
MEMORY
ADDRESS,
MAKE
SURE
THERE
IS
NO
OTHER
MEMORY
ASSIGNED
TO THE
SELECTED
ADDRESS.
The next
switch
setting
is
for
the
interrupt
vectors
and DMA
channel
selection.
The IBM-PC
has eight
(8) interrupt
vector
levels
and two levels
(0 & 1) are not
accessible
since
they
are
used
by
the
operating
system.
The remaining
6
vectors
are
available
to the
user.
The IBM-PC
interrupt
vector
map is
as
shown below
with
the
standard
assignments
of function
made by
IBM.
LEVEL
VECTOR
0
1
---------------
---------------
3"
-----------____
---------------
4
---------------
5
---------------
6
---------------
7
---------------
FUNCTION
[TIMER - SYSTEM ONLY)
[KEYBOARD - SYSTEM ONLY)
USER OR LPT2:
COMM2: ADAPTER
COMMl: ADAPTER
FIXED DISK OR LPT3:
FLOPPY DISKETTE DRIVES
PRINTER #l
(LPTl:)
The INTERRUPT LEVEL & DMA selector
switch
is
located
in
the
bottom
center
of the board.
The switch
is marked
INT (1 2 4) and
is set as follows:-
INTERRUPT
0
1
2
3
4
5
6
7
LEVEL
SW(2)-1
2
2
::
d":
SW(3)-2
UP
::
dn
up
a":
dn
SW(4)-4
up
RESERVED
UP
RESERVED
UP
UP
dn
dn
dn
dn
The standard
switch
setting
is vector
level
5 and is
shown in
bold
print.
It
is the users
responsibility
to select
an interrupt
level
that
does not
conflict
with
the
operating
system
hardware.
If
the
system
is using
a spooler
for
the printer
then
Interrupt
Level
7 will
be in use.
Note
that
the
interrupts
are
only
used
during
DMAtransfers,
therefore
if DMA is notusedthe
setting
is
irrelevant.
Page 7
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