GEM SK760 Owner's Manual page 300

TRACK SELECT
Address(H) Size (H)
00 20 00 00 00 01
SYSTEM OBJECT ACCESS MESSAGES
SYSTEM RESOURCE ACCESS
Messages relating to the RESOURCE ACCESS allow the transfer via MIDI of the same basic resources of the instrument that can be exported to
disk, and which are:
∑
System SETUP
∑
SOUNDS
∑
GLOBAL PRESETS
∑
STYLE PRESETS
∑
USER STYLES
∑
SONGS
Each type of resource can constitute several files, in which case, before transmitting, are compacted into a single data block..
The transmission can take place in handshake mode for higher speeds and better control of the data transmitted (the system automatically recog-
nizes the mode utilized according to the reply given or not after the transmission of the File Header Message).
The MIDI message transmitted consists of the following structure:
F0H = System Exclusive Message status
2FH = ID number (manufacturer ID) = GENERAL MUSIC
5cH = Command ID: 5=Resource Access, c=device ID(0-F)
ss = Subfunction ID
id = Model ID, 00 = WK4
cf = c = checksum (0-1), f = Data Format (0-3)
pp = packet number (optional)
<data> = (optional)
cc = checksum (optional)
F7H = EOX
The transmission of one of the available resources starts by sending a message (File Header message) to indentify the successve blocks of data
desired (File Data message).
Typically the files concerned can be relatively long, therefore it is better to subdevide the information into several brief packets which can be
individually tested and eventually retransmitted (in the case of using the handshake mode and the reception of an ACK reply confirms the correct-
ness of the packet received, while a reply of the type NACK forces the retransmission of the error packet).
Should it be necessar to interrupt the transmissoin, it is always possible to send the CANCEL command at any moment during the course of the
communication.
A WAIT command has also beed included for future implementations.
File Header message:
F0H = System Exclusive Message status
2FH = ID number (manufacturer ID) = GENERAL MUSIC
5cH = Command ID: 5=Resource Access, c=device ID(0-F)
01H = Subfunction ID = FILE HEADER
00 = Model ID, 00 = WK4
03H = not checksum, format 3 (octect)
<data> = 3 octects
F7H = EOX
File Data message:
F0H = System Exclusive Message status
2FH = ID number (manufacturer ID) = GENERAL MUSIC
5cH = Command ID: 5=Resource Access, c=device ID(0-F)
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A•36 Appendix
Range(H)
00 1F
Subfunction ID:
8
○ ○ ○ ○ ○ ○ ○ ○ ○ ○
Parameter Description
Selected 00 31
6
File Header 01H
File Data 02H
Resource Request 03H
Parametr Request 40H
Parameter Data 41H
ACK 7FH
NACK 7EH
CANCEL 7DH
WAIT 7CH
○ ○
Default
7