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Roland Exclusive Messages
1. Data Format for Exclusive Messages
Roland's MIDI implementation uses the following data format for all
Exclusive messages (type IV):
Byie
Description
POH
Exclusive Status
ait
Manufacturer ID (Roland)
DEV
Device 1D
MDL.
Modet 1D
eM
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, starting
with a Manufacturer [D immediately after FOH (MIDI version 1.0).
° Manufacturer ID: 41H
The Manufacturer ID identifies the manufacturer of a MIDI instrument that
sends an Exclusive message.
Value 41H represents Roland's Manufacturer
ID.
*Device ID: DEV
The Device [D contains a unique value that identifies individual devices in
the implementation
of several
MIDI
instruments.
It is usually set to
DOH-OFH, a value smaller by one than that of a basic channel, but value
OOH-1FH may be used for a device with several basic channels,
*Model ID: MDL
The Model
1D contains a value that 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 00H in one or more places to provide an
extended data field.
The following are examples of valid Model IDs, each
representing a unique model:
O1H
(2H
OSH
OOH, 01H.
OOH, 02H
OOH, 00H, 01M
*Command ID: CMD
The Command
ID indicates the function of an Exclusive message.
The
Command ID format may contain 00H in one or more places to provide an
extended
data field.
The following are examples of valid Command
IDs,
each representing a unique function:
OH
02H.
OBE
OOH, GLH
OOH, 02H
OOH, GOH, 01H
«Main data: BODY
This field contains a message to be exchanged across
an interface. The exact
data size and content will vary with the Model 1D and Command ID.
2. 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-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.
10
*One-way transfer procedure
(See Section 3 for
details.)
This procedure is suited to the transfer of a small amount of data. Tt sends
out an Exclusive message completely independent of the receiving device's
status.
Connection Diagram
Device A
Device B
MIDE OUT
7
MIDEIN,
MIDLOUT
MIDIIN
Connection at point 2 is essential for "Request data" procedures. (See Section
3)
¢Handshake-transfer procedure
(This device does
not use 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
Device A
Device B
MIDI GUT
MIDIIN
MIDEIN
2.
MIDIOUT
Connection at points 1 and 2 is essential.
Notes on the above 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.
3. One-way Transfer Procedure
'This procedure sends out data until it has all been sent and is used when the
messages are so short that answerbacks need not be checked.
For longer messages, however, the receiving device must acquire each
message in time with the transfer sequence, which inserts 20 milliseconds
intervals,
Types of Messages
| Message
Command 1D
Request data i | RQI(11H}
Data set 1
DTT 2H)
*Request data #1: RQ1 (11H)
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 RQI message, the remote device checks its memory for the
data address and size that satisfy the request.
Ef it finds them and is ready for communication, the device will transmit a
"Data set 1 (DT1)" message, which contains the requested data. Otherwise,
the device won't send out anything.
Byte
Description
POH
Exclusive Status
41H
Manufacturer 1D (Roland)
DEV
Device ID
MDL | Model ID
MH
Command ID
aaHi
Address MSB
i
1
f
LSB
ssHi
Size
MSB
\
:
i
i
LSB
sum
Check sum
FH
End of exctusive
4
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