Roland D-05 - MIDI Implementation; Request data RQD (41 H); Data set DAT (42 H)

38
MIDI Implementation
Byte Explanation
ssH Size MSB
LSB
sum Check Sum
F7H EOX (End Of Exclusive)
* The size indicates the address range of the entire data that is being requested; it is not the
number of bytes of data in a single “data set” message.
* For some models, the amount of data that can be transmitted at one time might be xed
depending on the type of data, and in some cases the data must be transmitted and received in
specic divisions or divided by addresses.
* The address and size are the same number of bytes, and are determined for each “model ID.”
* The check sum is the value that causes the lower seven bits to be zero when the address, the
size, and the check sum itself are added.
7 Request data “RQD” (41H)
This is transmitted when requesting the other device to transmit data. The address and size indicate
the data and the amount being requested.
If this message is received, and if that device is in a condition of being able to transmit data, and if
the address and size are appropriate, then it transmits the requested data as a “data set” message. If
not, the device transmits a “rejection” message.
Byte Explanation
F0H Exclusive status
41H Roland ID
DEV Device-ID
14H Model-ID (D-50)
41H Command-ID
aaH Address MSB
LSB
ssH Size MSB
LSB
sum Check Sum
F7H EOX (End Of Exclusive)
* The size indicates the address range of the entire data that is being requested; it is not the
number of bytes of data in a single “data set” message.
* For each model, the amount of data that can be transmitted at one time might be xed
depending on the type of data, and in some cases the data must be transmitted and received in
divisions of specic addresses.
* The address and size are the same number of bytes, and are determined for each “model ID.”
* The check sum is the value that causes the lower seven bits to be zero when the address, the
size, and the check sum itself are added.
7 Data set “ DAT” (42H)
This transfers the actual data.
Although each byte of the data has an address, this message allows the address of a single item
of data, or the starting address of multiple items of data, together with the data along, to be
transmitted in the order of the addresses.
According to the MIDI specication, messages other than realtime messages cannot interrupt an
exclusive message. In consideration of devices that implement “soft-thru,” Roland limits the amount
of data that is transferred in a single “data set” to a maximum of 256 bytes; for this reason, large
amount of data that exceed 256 bytes are divided and transmitted in multiple pieces.
Byte Explanation
F0H Exclusive status
41H Roland ID
DEV Device-ID
14H Model-ID (D-50)
42H Command-ID
aaH Address MSB
LSB
ssH Data
Byte Explanation
sum Check Sum
F7H EOX (End Of Exclusive)
* This message allows transfer of just the valid portion within the range indicated by the “data
request” or “data transmission request” message.
* For each model, the number of data items that can be transmitted at once might be determined
according to the type of data, or might have to be transmitted and received at divisions of the
specied address.
* The number of address bytes is determined for each “model ID.”
* The check sum is the value that causes the lower seven bits to be zero when the address, the
size, and the check sum itself are added.
7 Acknowledge “ACK” (43H)
This message is transmitted when a message such as “data transmit/receive request,” “data set,”
or “data end” was received, and that message was correctly received and the corresponding
preparations or processing were completed. After the other device receives this message, it
proceeds to the next operation.
Byte Explanation
F0H Exclusive status
41H Roland ID
DEV Device-ID
14H Model-ID (D-50)
43H Command-ID
7FH EOX (End Of Exclusive)
7 End of data “EOD” (45H)
This message is transmitted in order to inform the other device that the data has ended. After this
message, an “acknowledge” message is received from the other device, and then transfer ends.
Byte Explanation
F0H Exclusive status
41H Roland ID
DEV Device-ID
14H Model-ID (D-50)
45H Command-ID
7FH EOX (End Of Exclusive)
7 Communication error “ERR” (4EH)
If the message could not be received correctly, such as if check sum value does not match, then this
message is transmitted to inform the other device of the error. However, it is also permissible to end
communication by transmitting a “rejection” message instead of this message.
If this message is received, the last-transmitted message may be retransmitted once again, or a
“rejection” message may be transmitted to end communication.
Byte Explanation
F0H Exclusive status
41H Roland ID
DEV Device-ID
14H Model-ID (D-50)
4EH Command-ID
7FH EOX (End Of Exclusive)