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Roland Exclusive Messages
EE Data Format for Exclusiva Messages]
Roland's
MIDI
implementation
uses
the following data
format
far aii
exclusive messages
(type IV):
Byte
| Description
FoH
Exciusive status
ATH
Manufacturer
ID (Roland)
Dev
Device ID
Modest ID
Command
iO
Mein date
End of exclusive
z MIDI status,
FOH, F7H
An exclusive message must be flanked by a pair of status codes, starting
with a ManufacturerID immediately after FOH (MIDI versioni.o).
= Manufacturer ID: 41H
'The ManufactureriD identifies
the manufacturer of a MIDI instrument
thet triggers an exclusive message,
Value 41H represents Roland's
Manufacturer iD.
zDevicelD : DEV
The Device D contains a unique value that identifies the individual device
in the multiple Implementation of MIDI instruments. it is usually set to
noH
- OFH,
zhue smaller by one than that of a basic channel but
value OOH ~ IFH may be used [or a device with multiple basic channels.
z ModellD : MOL
The ModeklD contains a value that uniquely identifies one model from
another.
Different models, however, may share an identical ModelID if
they handle similar data.
The ModeltD
format may contain 00H in one or more places to. provide
an extended
data field. The following are examples
of valid ModelIDs.
each
representing
a unique
model:
DiH
02H
03H
NOH. 01H
00H, 02H
OO, OOH, DIH
=Command|ID:
CMD
The Command ID indicates the function of an exclusive message.
The
Commundi®
format may contain GOH in one or more
places to provide
un extended
dats
field. The following are examples
of valid Command-
IDs. cach representing a unique function:
Ot
azt
03H
OOH, 01H
OOH, 02H
OOH. OOH, 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 ModelID and
Command 10.
D
iE
Q
2 3 p S 3 F 5
Oo
oO
[5
[v]
S x g
E
= 3 È 3 2 B
3j
Adress
ping
technique
for transferring messages conforming
te ihe
data format
m in Section
1. M assigns a series of memory-
resident records-wavelorm and tone data, switch status, and parameters,
for
imple-Lo. specific locations in a machine-dependent
address space,
thereby
alluwing
access
to data
residing ai 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.
= Oneway transfer procedure
(Ses Section 3 for details;
This procedure is sulted for the transfer of a small amount of data.
It sends out an exclusive message completely independent of e receiving
device status.
Connection
Diagram
Devica (A)
Device (8)
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 dala transfer takes place. Handshaking ensures
that reliability and transfer speed are high enough lo handle a large
amount of data.
Connection Disgram
Device (A)
Device (B)
|
eT
— À e ris
MON
atit out
Connection
at paints
1 and 2 is essential,
Notes on the above two procedures
*
There are separate CommandDs
for different transfer procedures,
*
Devices
A and
B cannot exchange
data
unless
they
use
the seme
transfer procedure, share identical Device 1D and Model 1D, and are
ready for communication.
Oneway
Transfer Procedure
This procedure sends out data oll the way until it stops and is used
when the messages are so short that answerbacks need nol be checked,
For long messages, however, the receiving device must acquire euch
message in time with the transfer sequence, which inserts intervals of
at least 20 milliseconds in between.
Typas
of Messages
RQ
(1TH)
|?" (12H)
Request data !
Data set 1
zRequest data s
1. RQI
(ih)
This message is sent out when there is a need to acquire data fram
a device at the other end of the interface. It contains dats for the address
and size that specify designation and length, respectively, of data required.
On receiving an RQl message, the remote device checks iis memory for
the data address and size that satisfy the request.
Hf it finds them and is ready for communication, the device wii transmit
a "Data set i (DT1)"
message, which contains the requested data.
Otherwise, the device will send out nothing.
Byte
Description
FOH
sgive status
2H
Manufacturer ID (Roland)
DEV
Device 1D
MDL
Model ID
nH
Command ID
sah
Address MSB
ssH
Size
LSB
sum
Check
sum
F7H
End of exclusive
9727
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