Appendices

*The size of the requested data does not indicate the number of bytes that will make up a DT1 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 it 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 a bit pattern where the last 7 bits are zero when values for an address, size, and that checksum are summed.

•Data set 1: DT1 (12H)

This message corresponds to the actual data transfer process.

Because every byte in the data is assigned a unique address, a DT1 message can convey the starting address of one or more bits of data as well as a series of data formatted in an address-dependent order.

The MIDI standards inhibit non real-time messages from interrupting an Exclusive one. This fact is inconvenient for devices that support a “soft-thru” function. To maintain compatibility with such devices, Roland has limited the DT1 to 256 bytes so that an excessively long message is sent out in separate ‘segments’.

Byte

Description

F0H

Exclusive Status

41H

Manufacturer ID (Roland)

DEV

Device ID

MDL

Model ID

12H

Command ID

aaH

Address MSB

 

LSB

ddH

Data MSB

 

LSB

sum

Check sum

F7H

End of exclusive

 

 

*A DT1 message is capable of providing only the valid data among those specified by an RQ1 message.

*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 it is exchanged across the interface.

*The number of bytes comprising address data varies from one Model ID to another.

*The error-checking process uses a checksum that provides a bit pattern where the last 7 bits are zero when values for an address, size, and that checksum are summed.

•Example of Message Transactions

•Device A sending data to Device B

Transfer of a DT1 message is all that takes place.

Device A

[Data set 1] * More than 20m sec time interval.

[Data set 1]

[Data set 1]

Device B

•Device B requesting data from Device A

Device B sends an RQ1 message to Device A.

Checking the message, Device A sends a DT1 message back to Device B.

Device A

[Data set 1] * More than 20m sec time interval.

[Data set 1]

Device B

[Request data]

[Data set 1]

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Boss Audio Systems GS-10 owner manual Data set 1 DT1 12H, Example of Message Transactions