Roland FC-300 Manuale Utente

 

This procedure initiates a predetermined transfer sequence 
(handshaking) across the interface before data transfer takes place.

Handshaking ensures that reliability and transfer speed are high 
enough to handle a large amount of data.

 

fig.Connection-Diagram2.eps

 

Connection at points 1 and 2 is essential.

 

Notes on the above procedures

• There are separate Command IDs for different transfer 

procedures.

• Devices A and B cannot exchange data unless they use the same 

transfer procedure, share identical Device ID and Model ID, 
and are ready for communication.

This procedure sends out data until it has all been sent and is used 
when the messages are so short that answerbacks need not be 
checked.

For longer messages, however, the receiving device must acquire each 
message in time with the transfer sequence, which inserts 20 
milliseconds intervals. In this method, as for the receiving device, it is 
necessary to receive data correctly in time.

 

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 RQ1 message, the remote device checks its memory 
for the data address and size that satisfy the request.

If it finds them and is ready for communication, the device will 
transmit a “Data set 1 (DT1)” message, which contains the requested 
data.

Otherwise, the device won’t send out anything.

 

• 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 

Device (B)

MIDI IN

MIDI OUT

Device (A)

MIDI OUT

MIDI IN

1

2

 

Request data 1

RQ1 (11H)

Data set 1

DT1 (12H)

 

F0H

System Exclusive Status

41H

Manufacturer ID (Roland)

DEV

Device ID

MDL

Model ID

11H

Command ID

aaH

Address MSB

 :

 :

 :

 :
Address LSB

ssH

Size MSB

 :

 :

 :

 :
Size LSB

sum

Check sum

F7H

EOX (End of System Exclusive)

FC-300_e1.book 60 ページ ２００７年４月２４日　火曜日　午前１０時１０分