Roland
Exclusive
Messages
y
pData Format
for
Exclusive Messagasj
Roland's MIDI impiemenla lion uses the following
data format (or all
exclusive
messages {type IV)
:
Byte
Oesciotion
FOH Exclusive
slstus
41H
Manufacturer ID (Roland)
OEV
Device
ID
MOL
Model ID
CMD Command 10
[SODY] Main daia
F7H End of
.
otcfgsive
a
MIDI status: FOH. F7K
An
exclusive
mcssasc must be flanked by a pair of status codes, startins
Willi
a Manufacturer-ID immediately after FOM (MIDI
versionl.O).
s ManufacturerlD : 41
H
The
Manufacturer-ID identifies the manufacturer
o( a MIDI
instrument
that
triggers
an
exclusive
message.
Value
4IH represents Roland's
Manufacturer-
ID.
e Device ID: DEV
The
DevicclD
contains a
unique value that idcniifies
the
individual device
in the multiple implementation of MIDI instruments, tt is usually set to
OOH
-
OFH, a value smaller
by
one than that of a basic channel, but
value 00)1
-
tFII may be used (or a
device with
multiple basic channels.
s 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 i(
they handle similar data.
The ModeMD format may contain OOH in one or more places to provide
an extended daia field. The
following
are examples of
valid
Model
IDs.
each representing a unique model
;
out
02H
03H
OOH. OIH
OOH. 02H
OOH. OOH. OIH
ttCommantJID:
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 ot
valid Command-
IDs, each representing a unique function
:
OtH
02H
03H
OOH, OIH
OOH,
02H
OOH.
OOH.
OIH
::Main data : 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.
[Address mapped Data Transfer]
Address mapping is a
technique for transferring messages conforming
to the data formal given in Section 1. It assigns a
series of memory-
resident
records-waveform
and
tone
data,
switch status, and parameters,
(or example~io 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
ot
models and
data
categories. This technique
allows
use of
two different transfer
procedures : one-way transfer and handshake transfer.
One-way transfer procedure (See
Section 3 for details.)
This procedure
is suited for the transfer of a small anwunt
of data,
11 sends out an
exclusive
message compteicly independent
of a receiving
device
status.
Connaot ion Diagram
Device
(A) Oovic*
CB)
WOI OUT
MJO< >N
..
ma IN
MOOUT
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
thai reliability
and transfer speed are high enough to handle
a large
amount of data
Conntclion Diagram
Device (A) Device
(B)
MIOIOUT
MO m
MOl in
wa OUT
Connection at
points
1 and 2 is essential.
Notes on the above two procedures
*
There are separate Command-IDs (or 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 (or communication.
U
JOne-way Transfer Procedure]
This
procedure sends out data all the
way
until it stops and is used
when
the messages are so short that
answerbacks
need noi
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,
Typ«( of M«M(g«>
Messafls
Command 10
Request data
1
Data set t
RQl <HH)
DTI
{12H)
s Request data
al
: RQl (11H)
This message is sent out when there is
a need to acquire data from
a device at the other end
o(
the interface, it contains
data for the address
and size that specify designation and length, respectively,
of data re<iuircd.
On receiving an
RQl message,
the
remote
device
checks its memory for
the data address and size thai satisfy
the rcquesl.
If
it finds them
and
is
ready
for communication,
the
device win
transmit
a "Data set 1 (DTt)" message, which contains the requested
daia.
Oihcrwise, the device will send
out
nothing.
6vt8
Oescfiption
POH Exclusive
stalus
41H Manufacturer ID (Roland)
OEV Oevice
ID
MDL Model ID
11H Command ID
aaH Address MSB
LSB
SSH
Sije
MSB
LSB
sum
Check
sum
F7H end of exclusive
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