Roland TD-7 - Page 159

* The size oi the requested dale does not tndicztte the numher of bytes
that wiil make up at i)Tt message, hut represents the address fields
where the requested data resides.
=t= Sonic mndels are subject tn limitations in data format used fur a
singte transaction. Requested data. for exempte, may have a limit
in length or must he divided intn predetermined address fields before
it is exchanged across the interface.
=i= The same number et bytes comprises address and size data. which.
however. vary with the It-tndel-ll).
=l= The error elteekintt process uses a checl-tsum that provides a hit
pattern where the tees! significant T bits are zero when values for
an address. size. and that eheeksum are sttmtneti.
.~=Data set 1
; DT1 (1 2H1
This message cnrrespends to the actual data transfer process.
Because every byte in the data is assigned a unique address. Z1 DT1
message can convey ti"-‘ Siflflifltl address nt nne or more data as weil
as at series of dale forrnzttted in an arltlress dependent order.
The X-Ill)!
ertelusive
stzmdartts inhibit non-reel time messages {rem interrupting an
one. This feet is inconvenient for the devices that support a
"soft lhrout_:h" tne<:hanism. To maintain ct1m1.::1tii)ilit1t' with such devices,
Roland has timited the HT! to 2513 hyles so that an exc.essi\"e|3r tong
message i 5 SUI’?! till! lfi SCIJEIFHIL‘ 5CR¥'ii£‘I1l5.
fl77___;:_:_____
X Byte
_ :_7_ :7 7, 7, ;7_7_7_ :_7__;:7;_::7;77 :7 _71-at _ 7;7: 77 77:7" _;:77 7 7_7:;:_ _ :__ ‘
; Description
7 7 ' 7 7 7 7 77_ 7:7 7 <77 777 77_77 7 777 7 7 77777 77 777 77; 7,, _ _7_*-
F0!-I
t Ail-t
est»
it MDL
t 2t~t
D
--...r.>
I
Q.
-ct.
I
SUP“
i
i Exclusive ;
Marn.1far:turer ti") (Roland) ‘i
~ Device ID
Modei ID
1 Commend IO
Address MSB \
LS8
Data X
no‘
0
Check sum
F"?t--I M End of exclusive
* A DTI message is capable of providing only the vaiid data among
those specified by an RQI message.
* Same modets are subject to limitations in data format used for a
single transattdion. lteqtzesletl data. for example. may have a limit
in length or must be divided into predetermined address fields eefere
it is exchanged across the interface.
=t= The number oi bytes comprising: address data varies fmm one Medel-
tt) to another,
* The error checking process uses a checksurn that nrovides at bit
pattern where the least signitieant 7 hits are zero when vutues for
an utttlress. size. and that cheekstim are summed.
=¢ Example of
I Device
Massage Transactions
A sending data to Device it
Transfer of 21 I11‘! message is all that takes place.
Device cs)
{Data set 1] --------—-----—--IF
=t= More than 20m se ' '
[Data set 11
e ttrne tnternat.
-
b_bQ—flfi
[Data set i] -—-—--------------------I>-
7
Roland Exclusive Messages
‘Device It requesting data from Device A
Device B sends an RQI message to Device A. Checking the
message, Device A sends a UT! message hack to Device B.
[Data sat 1} fieuuest data]
{Data set 1] ---------------------be
=t= More than 20m sec time internai.
[Data set 1] --—--------—---—-----------D-
{Data set I] --———-—-—-—--------Iv