Roland R-8M Owner's Manual page 120

Roland Exclusive
Messages
= Request data
:
ROD
(41
H)
This message
is
sent out
when
there
is
3
ned
to acquire data
from a device
at
(he other end of
the interface.
It
contains data
for the address
and
size
that specify
designation and
length,
respectively, of data re<)uircd.
On
receiving
an
RQD
message, the
remote device checks
its
memory
(or
the data address and
size
which
satisfy the request.
It it
finds
them and
is
ready
for
communication, the device
will
transmit a "Data
set
(DAT)'
message,
which
contains (he
requested data. Otherwise,
it
will return a "Rejection
(RJC)"
message.
Byie Oesc
riot
ion
FOH
Exclusive status
41H Manufacturer
ID (Roland)
oev
Device ID
MOL
Model
ID
41H
Command
ID
agH Address
MSB
LS5
SSH
Size
MSB
LSS
sum Check sum
F7H End
of exctusivs
*Thc
size of the requested data
does not
indicate
the
numtwr
of liytcs that
make
up
a
'Data
set
(DAT)' message,
t)ut
represents the address
fields
where
(tic
requested data
rcsides-
ixSome models
arc subject to limitations
in
data format used
for
3
sinitle transaction.
Requested data, for example,
may
have
a limit in length or
must be divided
into
predetermined
address
fields Ixtforc
it is
exchanged across (he
interface.
*Thc same number
of bytes comprises address
and
size daia.
which.
hoivc\'er,
vary wiih
the
Model
ID.
*The
error
checking process uses
a checksum
that provides
a
bit
patiem
where
(he
least significant
7
bits
arc zero
when
values
for
an
address, site,
and
that
cheeKsum
are
summed.
:
Data
set
:
OAT
(42H)
1'his
message corresponds
to the actual daia
transfer process.
Because every byte
in (t>e
data
is
assigned a unique
address,
the
message can
convey
the starting address of
one
or
more
data as well as a
series
of data formatted
in
an address-
dependent order.
Aiihou»{b the .MIDI standards
inhibit
non-real time messages
from interrupting
an exclusive one, some devices support a
"sofi'ihrouKh"
mechanism
for such interrupts.
To maintain
compatibility with such devices, Roland has
limited
the D.'\T to
256
bytes
so
that
an excessively long
message
is
sent out
in
separate scRmcnis.
Byte
Description
FOH
Exclusive status
4IH Manufacturer
ID
(Roland)
DEV
Device
10
MDL
Model
ID
42H Command
iD
aaH
Address
MSB
LSB
dOH
Data
sum Check
sum
F7H End of exclusive
*.\
DAT
message
is
capable of providing only
the valid data
among
those specified
by an
RQD
or
WSD
message.
«Some
models are subject to timi(3(ions in
data format used
tor
a single transaction.
Requested
data, for example,
may
have a limil
in
length or
must be divided
into
predetermined
address fields before
it is
exchanged acn^ss the
interface.
• The number
of bytes comprising address data varies
from
one model ID to another.
«Thc
error checking process uses a
checksum
that
provides
a bit
pattern
where
the least significant
7
bits
arc zero ivhen
valties tor
an
address,
size,
and
that
checksum are
summed.
:
Acknowledge:
ACK
clSH)
This
message
is
sent out
when
rto
error
was
delected
un
reception
of a
WSa
DAT, "End
of data (EOD)', or
some
other
message and a
requested setup or
aciitwi
is
conmletc. Unless
ii
receives
an
ACK
message,
the device
at
the other end «in
not proceed
to
the next operation.
Byte
Ds
scrip lion
FOH
Exclusive status
4IK
Manufacturer ID (Roland)
DEV
Oeviea
ID
MDL
Model
ID
43
H Command
ID
F7H
End of exclusive
=
End
of
data
EOD
(45H)
This message
is
sent
out
to
inform a remote device of the
end
ot a
message, (iimmunicatioo, however,
will not
tome
lo
an
end
unless the
remote device returns an .\CK
IUL^^41W evi-n
though an
EOD
message was
transmitted.
Byte Description
FOH
Exclusive
status
41
H
Manufacturer ID (Roland)
DEV
Device ID
MDL
Model ID
4SH
Command
10
F7H
End ot exclusive
:
Communications
error
:
ERR
(4EH)
1'his
message warns
the remote device ut a
Lummunica
lions
fault
encountered during message transmission due.
f<ir
example,
to
a checksum
error.
An
UUlt message may
lie
replaced
wiih a
"Rejection
(WO"
one.
which
icrminaics the
current message
transaction in
midsircam.
When
it
receives
an ERR
message, (he senilinc device ma>-
either attempt
to
send out the
last
messaKO a second time or
terminate communication by sending
out
an
\i)C nK-f^in.:
Byco Description
FOH
Exclusive status
41H
Manufacturer
ID
(Roiand)
DEV
Device
10
MDl.
Model
ID
4EH Command
ID
F7H
End of exclusive
:
Rejection
:
RJC (4FH)
This
message
is
sent out
when
there
is
a need lo terminate
communication by overriding the current ntcM^xe.
An
iiJC
message win be
triggered
when
;
•
a
WSD
or
RQD
message has
spccifiiil
an
iJJcKjl data addiv.v.
or size.
•
the dev'ice is
not ready
for (.'i)inniiiiii(jLl«n.
•
an
illegal
number of addresses or datu has
i>ocn deiecuil.
•
data (ransfer has been
terminated
liy
on
niuraKir,
•
a communications error
has
occurrwl.
An ERR
message may be sent out by a
deviui: iin either side
of the
interface.
Communicatinn must
\k
tcrniiiiuii.il
immediately
when
cither side irisKcrs
an
liKIi
luessaw.
Byte
Oescription
FOH
Exclusive status
41
H
Manufacturer
ID
(Roland)
DEV
Device
10
MDL
Model ID
4FH
Command
10
F7H
End of exclusive
118