EasyManuals Logo
Home>Korg>Synthesizer>DSS-1

Korg DSS-1 Service Manual

Korg DSS-1
74 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Page #34 background imageLoading...
Page #34 background image
9.
SYSTEM
EXPLANATION
1.
CPU
SYSTEM
The
DSS-1
digital
sampling
synthesizer
has
8
voices
(16
oscillators),
all
functions
are
controlled
by
software.
A
dual
CPU
system
is
employed.
The
division
of
labor
between
the
CPU
is
as
follows.
•
CPU
1
(8085A-2,
KLM-780)
•
CPU
2
(63B03X,
KLM-781)
1.
LCD
and
LED
indicators
1.
KEY
scan,
KEY
assign
2.
Panel
switch
input
processing
2.
MIDI
processing
3.
FDD
control
3.
VCF/VCA
control
4.
Tone
generator
processing
4.
DDL
control
5.
Interface
with
CPU
2
5.
Foot
switch
input
processing
6.
Interface
with
CPU
1
The
foliowings
are
examples
of
the
division
of
labor
in
specific
operations.
■
Sound
data
processing
Sound
data
such
as
waveform
data
and
VCFA
data
are
all
stored
on
a
floppy
disk
(FD).
CPU
1
supervises
this
storage
operation.
In
addition,
waveform
data
are
transferred
to
a
DRAM
under
the
supervision
of
CPU
1.
VCFA
data
are
transferred
to
CPU
2.
■
KEY
input
processing
CPU
2
does
KEY
scanning
and
KEY
assigning.
Whenever
KEY
goes
ON
or
OFF,
CPU
2
performs
VCFA
ON/OFF
processing,
and,
at
the
same
time,
output
to
MIDI
is
performed.
Data
are
also
transferred
to
CPU
1,
and
CPU
1
performs
TG
ON
processing.
■
PITCH
BEND,
MASTER
TUNE
processing
CPU
2
performs
A/D
conversion
of
CV
from
the
bender
and
TUNE
VR.
If
there
is
a
change,
the
changed
values
are
transferred
to
CPU
1,
CPU
1
ac
cesses
TG
and
the
musical
interval
is
changed
ac
cordingly.
I
Panel
switch
input
processing;
LCD
And
LED
in
dications
CPU
1
performs
a
switch
scan
and
gives
the
necessary
LCD
and
LED
indications.
I
DATA
ENTRY
A,
B
potentiometer
value
inputs
CPU
2
performs
A/D
conversion
of
CV
and
then
changes
values
as
necessary.
The
changed
values
are
transferred
to
CPU
1
and
then
processed
by
CPU
1.
If
a
cutoff
is
edited
in
PROGRAM/PARAMETER
mode,
when
DATA
ENTRY
B
is
moved
CPU
2
trans
fers
that
value
to
CPU
1
and
the
processing
is
per
formed
by
CPU
1.
Then
the
value
is
transferred
back
to
CPU
2,
and
CPU
2
changes
the
VCF
CUTOFF
CV.
I
Sampling
The
length
of
the
sampling
frequency
is
controlled
by
CPU
1.
Sampling
start
trigger
level
data
are
then
transferred
to
CPU
2,
and
CPU
2
controls
the
CV
in
accordance
with
those
data.
I
Hand
drawing
After
hand
drawing
is
started,
CPU
2
performs
A/D
conversion
of
DATA
ENTRY
A
data
every
16
ms.
The
resulting
values
are
transferred
to
CPU
1.
CPU
1
stores
those
values
in
the
RAM.
When
512
values
have
been
transferred,
the
operation
terminates.
CPU
1
produces
8
waveforms
(for
8
octaves)
from
those
data
and
transfers
them
to
the
DRAM.
I
Sine
synthesis
CPU
1
performs
the
synthesis
based
on
the
sine
table
in
the
EPROM,
produces
8
waveforms
(for
8
octaves)
and
transfers
them
to
the
DRAM.
2.
Explanation
of
custom
LSI
In
the
DSS-1,
since
it
is
necessary
to
transfer
a
large
quantity
of
data
at
high
speed,
the
DMA
(DIRECT
MEMORY
ACCESS)
system
is
adopted.
In
this
system,
data
are
transferred
directly
between
I/O
and
memory
without
going
through
the
CPU
registers.
The
LSIs
developed
for
this
purpose
are
the
custom
GATE
AR
RAY
^PD65030G-043
(GA-I)
and
/*PD65040G-099
(GA-
n).
The
GA-I
receives
DMA
requests
on
16
channels
(maximum
of
24
channels),
encodes
them
and
gener
ates
timing.
The
GA-E
stores
8 channels
worth
of
generates
timing.
The
GA-n
stores
8
channels
worth
of
memory
addresses,
increments
addresses
in
response
to
requests
and
outputs
in
accordance
with
the
GA-I
timing.
In
the
DSS-1,
two
GA-IIs
are
needed
for
each
GA-I
to
cover
16
channels.
■
Caution
Both
the
GA-I
and
GA-n
use
80-pin
flat
packages.
Use
caution
in
repair
and
replacement.
3.
FDD
(FLOPPY
DISK
DRIVE)
A
FDD
(MD350)
is
used
to
READ/WRITE
sound
parameter
data
on
an
FD
(3.5-inch
FLOPPY
DISK).
The
basic
mechanical
movement
in
the
FDD
is
that
when
the
DISK
rotates
the
HEAD
moves
in
the
radial
direction.
It
is
made
up
of
a
great
many
mechanical
parts.
Special
jigs
developed
by
the
manufacturer
are
needed
for
repair
and
adjustment,
so
repair
by
anyone
other
than
the
manufacturer
is
impossible.
Consequently,
complete
units
must
be
replaced.
Judge
whether
an
FDD
is
malfunctioning
by
swapping
FDDs.
32
Scan by Manual Manor
http://www.markglinsky.com/ManualManor.html

Table of Contents

Other manuals for Korg DSS-1

Preview: Owner's Manual
Owner's Manual312 pages
Preview: User Guide
User Guide16 pages

Questions and Answers:

Question and Answer IconNeed help?

Do you have a question about the Korg DSS-1 and is the answer not in the manual?

Korg DSS-1 Specifications

General IconGeneral
BrandKorg
ModelDSS-1
CategorySynthesizer
LanguageEnglish

Related product manuals