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Roland Exclusive Messages
| Data Format for Exclusive Messages
Roland's MIDI implementation uses the following data
format for all exclusive messages (type IV):
FOH
41H
DEV
MDL
CMD
(BODY)
F7H
Exclusive status
Manufacturers ID (Roland)
Device ID
Model ID
Command ID
Main data
End of exclusive
# MIDI status: FOH, F7H
An exclusive message must be flanked by a pair of status co-
des, starting with a Manufacturers-ID immediately after FOH
(MIDI version 1.0).
# Manufactures-ID: 41H
The Manufactures-ID identifies the manufacturer of a MIDI in-
Strument that triggers an exclusive message. Value 41H repre-
sents Roland's Manufactures-ID.
# Device-ID: DEV
The Device-ID contains a unique value that identifies the indi-
vidual device in the multiple implementation of MIDI instru-
ments. It is usually set to OOH-OFH, a value smaller by one than
that of a basic channel, but value OOF-1FH may be used for a
device with multiple basic channels.
# Model-ID: MDL
The model-ID contains a value that uniquely identifies one mo-
del 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 E
each representing a unique model:
1H
02H
03H
OOH, 01H
00H, 00H, 01H
* Command-ID: COM
The Command-ID indicates the function of an exclusive mes-
sage. The Command-ID format may contain ООН in one or mo-
re places to provide an extended data field. The following are
examples of valid Model-IDs, each representing a unique func-
tion:
01H
02H
03H
00H, 01H
00H, оон, 01H
# Main data: BODY
This field contains a message to be exchanged across an inter-
farce. 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 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 loca-
tions 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.
** One-way transfer procedure (See Section 3 for details)
This procedure is suited for the trasnfer of a small amount of
data. It sends out an exclusive message completely indepen-
dent of a receiving device status.
106
Connection Diagram
Device (A)
Device (B)
MIDI OUT
MIDI IN
MIDI OUT
MIDI IN
Connection at point 2 is essential for «Request data» procedu-
res (See Section 3).
One-way Transfer Procedure
This procedure sends out data all the way until it stops when
the messages are so short that answer backs need not be
checked.
For long messages, however, the receiving device must acqui-
re each message in time with the transfer sequence, which in-
serts intervals of at least 20 milliseconds in between.
Types of Messages
Message
Command 10
вот (11H)
от: (12H)
Request data 1
Data set 1
# Request data 1: RO1 (11H)
This message is sent out when there is no need to acquire data
from a device at the other end of the interfarce. tt contains da-
ta for the address and size that specify designation and length,
respectively, of data required.
On receiving and ВОТ 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 (DT1)» message, which contains the re-
quested data. Otherwise, the device will send out nothing.
Exclusive status
Manufacturers ID (Roland!
Device ID
Model ID
Command 10
Address MSp
Byte
Check sum
End of exclusive
* The size of the requested data does not indicate the number
of bytes that will make up a OT1 message, but represents
the address fields where the requested data resides.
* Some models and data are subject to limitations in data for-
mat used for a single transaction. Requested data, for exam-
ple, may have a limit in length or must be divided into prede-
termined address fields before it is exchanged across the in-
terface.
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