Roland LA SOUND MODULE CM-32L Owner's Manual page 24

z Data set:
zRequest data: ВОЮ (41H)
This message is sent out when there is a need to acquire data
from a device at the other end of the interface. It contains data
for the address and size that specify designation and length,
respectively, of data required.
On receiving an RQD message, the remote device checks its
memory for the data address and size which salisfy the request.
ff it finds them and is ready for communication, the device will
transmit а "Data set (DAT)" message, which contains the
requested data, Otherwise, it will return а "Rejection. (RJC)"
message.
Byte Description
Exclusive status
Manufacturer ID (Roland)
Device ID
Model ID
Command ID
Address MSB
158
MSB
LSB
Check sum
End of exclusive
* The size of the requested data does not indicate the number
of bytes that таке up а "Data sel (DAT)" message, but
represents the address fields where the requested data
resides.
*Some models are subject to limitations in data format used
for a single transaction. Requested data, for example, may
have a limit in length or must be divided into predetermined
address fields before й is exchanged across the interface.
* The same number of bytes comprises address and size data,
which, however, vary with the Model - ID.
* The error checking process uses a checksum that provides
а bit pattern where the least significant 7 bits are zero when
values for an address, size, and that checksum are summed.
DAT (42H)
This message corresponds io the actual data transfer process.
Because every byte in the 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.
Although the MIDI standards inhibit non - real time messages
from interrupting an exclusive one, some devices support а
"soft ~ through" mechanism for such interrupts. To maintain
compatibility with such devices, Roland has limited the DAT to
256 bytes so that an excessively long message is sent out in
separate segments.
Exclusive status
Manufacturer ID (Roland)
Device ID
Mode! 10
Command ID
Address М5В
LSB
Data
Н
Check sum
End of exclusive
+ Acknowledge :
+ End of data:
*A DAT message is capable of providing only the valid data
among those specified by an RQD or WSD message.
*Some models are subject to limitations in dala format used
for a single transaction. Requested data, for example, may
have a limit in length or must be divided into predetermined
address fields before it is exchanged across the interface.
*The number of bytes comprising address data varies from
one model 1D to another.
*The error checking process uses а checksum that provides
a bit pattern where the least significant 7 bits are zero when
values for an address, size, and that checksum are summed.
ACK (43H)
This message is sent out when no error was detected on
reception of а WSD, DAT, "End of data (EOD)", or some other
message and a requested setup or action is complete. Unless
it receives an ACK message, the device at the other end will
not proceed to the next operation.
Exclusive status
Manufacturer ID (Roland)
Device ID
Modet ID
Command Ю
End of exclusive
EOD (45H)
This message is sent out to inform a remote device of the end
of a message, Communication, however, will not come lo an
end unless the remote device returns ап ACK message even
though an EOD message was transmitted.
Exclusive status
Manufacturer ID (Roland)
Device 0
Моде! ID
Command ID
End of exclusive
z Communications error: ERR (4EH)
This message warns the remote device of a communications
fault encountered during message transmission due, for
example, to a checksum error. Ап ERR message may be
replaced with a "Rejection (ВЖ) one, which terminates the
current message transaction in midstream.
When it receives an ERR message, the sending device may
either attempt to send out the last message a second time or
terminate communication by sending out an RIC message.
Exclusive status
Manufacturer ID (Roland)
Device ID
Model ID
Command 0
End of exclusive