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Roland
Exclusive
Messages
1. [GES Format for Exclusive Messages
Roland's MIDI implementation uses the following data format
for alt exclusive messages (type 1V) :
Byte
Description
FOH
Exclusive
status
4lK
Manufacturer
ID (Roland)
DEV
Device
ID
MOL
Model
iD
cmd
Command
!D
[goby]
Main
data
FTH
End of exclusive
# MID!
status:
FOH, F7H
An exclusive message must be flanked by a pair of status
codes, starting with » Manufacturer—ID immediately after FOH
(MIDI version1.0),
# Manufacturer- ID:
41H
The Manutacturer—ID identifies the manufacturer of a MIDI
instrument
that triggeres an exclusive message.
Value 41H
represents Roland's Manufacturer—!D.
# Device~ ID:
DEV
The Device-ID contains a unigue value that Identifies the
individual device in the multiple implementation
of MIDI
instruments. Ht is usually set to OOH ~ OFH, a value smailer
by one than that of a basic channel, but value OOH — 1FH
may be used for a device with multiple basic channels,
# Model~ 1D:
MDL
The Model~{D 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
ta provide an extended data field. The following are exampies
of valid Model—IDs, each representing a unique model :
OH
02H
03H
OOH, 01H
OOH, 02H
00H, OOH, OH
# 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 :
OtH
02H
03H
00H, O1H
OOH, O2H
OOH, OCH, 01H
# 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.
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
jocatians
in
a
machine~dependent
address
space,
thereby
allowing
access
to data
residing
at ihe address
a message
specilies,
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.
Connection
Diagram
Device (A)
Device (B)
waint OUT
sane wv
Connectiunal point2 is essential for "Request data" procedures.
(See Sectiun3.)
Connection
Diagram
Device (8)
Device
(A)
Connectionat points] and 2 is essential,
Notes
on
the above
two
procedures
*There
are
scparate
Command~IDs
for different transfer
procedures.
%DevicesA
and B cannot
exchange data unless they use the
same transice procedure, share identical Device—ID and Model
ID, and are ready for cammunication,
Effone
way Transfer
Procedure
For long messages, however, the receiving device must acquire
each message in time with the Lransfer sequence, which inserts
intervals of at least 20milliseconds in between.
Types of Messages
Request data ! | RQ1 (13H)
Data
set
|
DT)
(12H)
# Request
data
#1:
RQ1
(11H)
This message is sent out when there is a need to require data
{rom a device al the other end of the interface, It contains data
for the address and size that specify designation and length,
respectively, of dala required,
On
receiving
an
RQI
message,
the remote
device checks its
memory for the dala address and size that satisfy the request.
Byte
Description
FOH
Exciusive
status
41H
Manufacturer ID (Roland)
DEV
Device ID
MDL,
Model 1D
11H
Command ID
aay
Address
MSB
sa
ssl
Size
MSB
use
sum
Check
sum
FIH
End
of
exclusive
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