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1. Data Format for Exclusive Messages
RolandÕs MIDI implementation uses the following data for-
mat for all Exclusive messages (type IV):
Byte
Descripción
F0H
Estado Exclusivo
41H
ID Fabricante (Roland)
DEV
ID Aparato
MDL
ID Modelo
CMD
ID Comando
[BODY]
Datos Principales
F7H
Fin de Exclusiva
MIDI status: F0H, F7H
An Exclusive message must be flanked by a pair of status
codes, starting with a Manufacturer ID immediately after
F0H (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 RolandÕs Manufacturer ID.
Device ID: DEV
The Device ID contains a unique value that identifies indivi-
dual devices in the implementation of several MIDI instru-
ments. It is usually set to 00H-0FH, a value smaller by one
than that of a basic channel, but value 00H-1FH may be
used for a device with several basic channels.
Model ID: MDL
The Model ID 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 pla-
ces to provide an extended data field. The following are
examples of valid Model IDs, each representing a unique
model:
01H
02H
03H
00H, 01H
00H, 02H
00H, 00H, 01H
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 follo-
wing are examples of valid Command IDs, each represen-
ting a unique function:
01H
02H
03H
00H, 01H
00H, 02H
00H, 00H, 01H
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MENSAJES EXCLUSIVOS ROLAND
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 ID 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.
One-way transfer procedure
This procedure is suited to the transfer of a small amount of
data. It sends out an Exclusive message completely inde-
pendent of the receiving device's status.
Connection Diagram
Aparato (A)
MIDI OUT
MIDI IN
Connection at point 2 is essential for ÒRequest dataÓ proce-
dures. (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
Aparato (A)
MIDI OUT
MIDI IN
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.
(See Section 3 for details.)
Aparato (B)
1
MIDI IN
MIDI OUT
2
Aparato (B)
1
MIDI IN
MIDI OUT
2
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