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Roland
Exclusive
Messages
Data Format
for
Exclusive
Messages
Roland's
MID!
implementation uses
the
following data
format
for
all
exclusive
messages
(type IV):
Byte
Description
FOH
Exclusive status
41H
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, staning with a
Manufacturer-ID immediately
after
FOH
(MIDI
version
1
.0).
#Manufacturer-iD:
41
The
Manufacturer-ID
identifies
the
manufacturer of
a
MIDI
instrument
that triggers
an
exclusive message.
Value
41H
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
instruments.
It
is
usually
set lo
OOH
-
OFH,
a
value
smaller
by
one
than
that
of
a basic
channel, but value
OOH
—
1FH may
be used
for a
device with
multiple basic channels.
#Modei-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.
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
#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
OOH,
02H
OOH, OOH,
OIH
#Maindata:
BODY
This
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 (See
Section 3
for
details.)
This procedure
is
suited for
the transfer
of
a
small
amount
of
data.
It
sends out an
exclusive me.ssage
completely independent of
a
receiving
device
status.
Connection Diagram
Device
(A)
Device
(B)
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 lakes place.
Handshaking
ensures
that reliability
and
transfer
speed
are
high
enough
to
handle
a large
amount
of
data.
Connection
Diagram
Device
(A)
Device
(B)
MIDI
OUT
MIDI
IM
MIDI
IN
MIDI
OUT
Connection
at
points
1
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.
One-way
Transfer
Procedure
This
procedure sends
out data
all
the
way
until
it
slops
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
lUlessages
Message
Command
ID
Request
data
1
Data
set
1
RQ1
(11H)
DTI
(12H>
#Request
data #1
:
RQ1
(1
1
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
mes.sage,
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
nothing.
Address-mapped
Data Transfer
Address
mapping
is
a
technique
for transferring
messages conforming
to
the
data
format
given
in
Section
I.
It
assigns
a series
of
memory-resident records-waveform and
tone
data,
switch
status,
and
parameters,
for
example~to
specific
locations
in
a
machine-dependent
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.
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
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