Advertisement
Roland
Exclusive
Messages
J
Data
Format
for
Exclusive
Messages
|
Roland's
MIDI
implementation
uses the following data format for
all
exclusive
messages
(type iV):
Byte
Description
FOH
Exclusive slalus
41
H
Manufacturer
ID (Roland)
DEV
Device
ID
MDL
Model
ID
CMD
Command
ID
[BODY)
Main
data
F7H
End
of
exclusive
!
MIDI
Status:
FOH,
F7H
An
exclusive
message must be
flanked
by
a pair
of
status
codes, sianing
with
a
Manufacturer-ID immediately
after
FOH
(MIDI
versionl.O).
Manufacturer-ID: 41
H
The
Manufacturer-ID
identifies
the
manufacturer of a
MIDI
instrument
that
triggers
an exclusive message.
Value
4IH
represents
Roland's Manufacturer-
ID.
Device-ID:
DEV
The
Device-ID
contains a
unique
value
that identifies
the individual
device
in
the multiple
implementation of
MIDI
instrumenis.
It
is
usually
set
to
OOH
—
OFH,
a
value smaller
by one
than
that
of
a basic channel, hut value
OOH
—
IFH may
be used
for a
device with
multiple basic channels.
Model-ID:
MDL
The Model-ID
contains a value
that
uniquely
identifies
one model from
another. Different
models, however,
may
share
an
identical
Model-ID
if
they
handle
similar
data.
i
One-way
transfer
procedure
(See Section 3
for
details.)
This procedure
is
suited for the transfer
of
a small
amount
of
data.
It
sends
out
an
exclusive
message
completely independent of
a receiving
device
status.
Connection Diagram
Dtr/ictW
OvA^tfS)
MtDIOUT
MIOIIN
MIDI
114
MIDI
OUT
^-.2__.
Connection
at
point
2
is
essential for
"Request
data" procedures,
(See
Section
3.)
Handshake-transfer procedure
(This
device
does
not cover
this
procedure)
This procedure
initiates
a predetermined
transfer
sequence (handshaking)
across
the interface
before data
transfer takes place.
Handshaking
ensures
that
reliability
and
transfer
speed
are
high
enough
to
handle a
large
amount
of
data.
Connection Diagram
D«vlC8(A)
Oniu(B)
-
UW
IN
MIDI
out
MIDIIN
M
2
Connection
at
points
I
and 2
is
essential.
Notes
on
the
above two procedures
•
There
are separate
Command-IDs
for different transfer
procedures.
•
Devices
A
and
B
cannot
exchange
data unless they use the
same
transfer
procedure, share
identical
Device-ID and
Model
ID,
and
are
ready
for
communication.
The
Model-ID
format
may
contain
OOH
in
one
or
more
places
to
provide an
extended
data
field.
The
following
are
examples
of
valid
Model-IDs, each
representing
a unique model:
OIH
02H
03H
OOH,
OIH
OOH,
02H
OOH, OOH,
OIH
I
Command-ID:
CMD
The
Command-ID
indicates the function
of an exclusive message.
The
Command-ID
format
may
contain
OOH
in
one
or
more
places
to
provide
an
extended
data
field.
The
following
are
examples of
valid
Command-IDs,
each
representing a
unique
function:
OIH
02H
03H
OOH,
OIH
00H,02H
OOH, OOH,
OIH
Main
data:
BODY
JTiis field
contains
a message
to
be exchanged
across
an
interface.
The
exact
data
size
and
contents
will
vary with
the
Model-ID
and
Command-ID.
One-way
Transfer
Procedure
[^
Address-mapped
Data Transfer
Address
mapping
is
a
technique
for transferring
messages conforming
to the
data
format given
in
Section
1. It
assigns a
series
of
memory-
res
idem
records--waveform and
tone
data,
switch
status,
and
parameters,
for
example—
to
specific locations
in
a
machine
-de
pendent address
space,
thereby allowing access
to
data residing
at
the address
a message
specifies.
Address-
mapped
data
transfer
is
therefore
independent of
models and
data
categories.
This technique allows use of
two
different transfer
procedures:
one-way
transfer
and handshake
transfer.
This procedure sends out data
all
the
way
until
it
stops
and
is
used
when
the
messages
are
so
short that
answerbacks need
not
be
checked.
For
long messages,
however,
the
receiving device
must
acquire
each
message
in
time with
the transfer
sequence,
which
inserts intervals
of
at least
20
milliseconds
in
between.
Types
of
Messages
tvleddage
Command
ID
Request
data
1
Data
set
1
RQl
(11H)
DTI
(12H)
Request
data
#1
:
RQl
(11
H)
This
message
is
sent out
when
there
is
a
need
to
acquire data
from
a
device
at
the
other
end of
the
interface.
It
contains data for the address
and
size
that
specify designation
and
length, respectively,
of
data
required.
On
receiving
an
RQl
message,
the
remote device checks
its
memory
for the
data address
and
size that satisfy the request.
If
it
finds
them
and
is
ready
for
communication,
the
device
will
transmit a
"Data
set
1
(DTI)" message, which
contains
the
requested
data.
Otherwise,
the device
will
send out
nodiing.
Byte
Description
FOH
Exclusive status
41H
Manufacturer
ID (Roland)
DEV
Device
ID
MDL
Model
ID
11H
Command
ID
aaH
Address
MSB
LSB
ssH
Size
MSB
'
LSB
sum
Check
sum
F7H
End
of
exclusive
45
Advertisement
