Supplementary material, Appendix, 7 decimal and hexadecimal table – Roland V-8HD HDMI Video Switcher User Manual
Page 87: 7 midi message examples, 6 how to calculate the checksum
87
Appendix
3. Supplementary Material
7
Decimal and Hexadecimal Table
(Hexadecimal Numbers are Indicated by ‘H’)
In MIDI documentation, data values and addresses/sizes of exclusive messages etc.
are expressed as hexadecimal values for each 7 bits.
The following table shows how these correspond to decimal numbers.
D
H
D
H
D
H
D
H
0
00H
32
20H
64
40H
96
60H
1
01H
33
21H
65
41H
97
61H
2
02H
34
22H
66
42H
98
62H
3
03H
35
23H
67
43H
99
63H
4
04H
36
24H
68
44H
100
64H
5
05H
37
25H
69
45H
101
65H
6
06H
38
26H
70
46H
102
66H
7
07H
39
27H
71
47H
103
67H
8
08H
40
28H
72
48H
104
68H
9
09H
41
29H
73
49H
105
69H
10
0AH
42
2AH
74
4AH
106
6AH
11
0BH
43
2BH
75
4BH
107
6BH
12
0CH
44
2CH
76
4CH
108
6CH
13
0DH
45
2DH
77
4DH
109
6DH
14
0EH
46
2EH
78
4EH
110
6EH
15
0FH
47
2FH
79
4FH
111
6FH
16
10H
48
30H
80
50H
112
70H
17
11H
49
31H
81
51H
113
71H
18
12H
50
32H
82
52H
114
72H
19
13H
51
33H
83
53H
115
73H
20
14H
52
34H
84
54H
116
74H
21
15H
53
35H
85
55H
117
75H
22
16H
54
36H
86
56H
118
76H
23
17H
55
37H
87
57H
119
77H
24
18H
56
38H
88
58H
120
78H
25
19H
57
39H
89
59H
121
79H
26
1AH
58
3AH
90
5AH
122
7AH
27
1BH
59
3BH
91
5BH
123
7BH
28
1CH
60
3CH
92
5CH
124
7CH
29
1DH
61
3DH
93
5DH
125
7DH
30
1EH
62
3EH
94
5EH
126
7EH
31
1FH
63
3FH
95
5FH
127
7FH
D: decimal
H: hexadecimal
* Decimal expressions used for MIDI channel, bank select, and program change are 1
greater than the decimal value shown in the above table.
* Hexadecimal values in 7-bit units can express a maximum of 128 levels in one byte
of data. If the data requires greater resolution, two or more bytes are used. For
example, a value indicated by a hexadecimal expression in two 7-bit bytes aa bbH
would be aa x 128 + bb.
* Data marked “nibbled” is expressed in hexadecimal in 4-bit units. A value expressed
as a 2-byte nibble 0a 0bH has the value of a x 16 + b.
What is the decimal expression of 5AH?
From the preceding table, 5AH = 90
What is the decimal expression of the value 12 34H given as hexadecimal for each 7
bits?
From the preceding table, since 12H = 18 and 34H = 52
18 x 128 + 52 = 2356
What is the decimal expression of the nibbled value 0A 03 09 0D?
From the preceding table, since 0AH = 10, 03H = 3, 09H = 9, 0DH = 13
((10 x 16 + 3) x 16 + 9) x 16 + 13 = 41885
What is the nibbled expression of the decimal value 1258?
16) 1258
16) 78... 10
16) 4... 14
0... 4
Since from the preceding table, 0 = 00H, 4 = 04H, 14 = 0EH, 10 = 0AH, the answer is
00 04 0E 0AH.
7
MIDI Message Examples
9n is a note on status and n is the MIDI channel number.
As 2H = 2, 3EH = 62 and 5FH = 95, this is a note on message of MIDI CH =3 , note
number 62 (D4) and velocity 95.
CnH is program change status, and n is the MIDI channel number.
As EH = 14 and 49H = 73, this is a program change message of MIDI CH = 15 and
program number 74 (in the GS sound map, Flute).
7
Example of an Exclusive Message and Calculating a Checksum
Roland Exclusive messages are transmitted with a checksum at the end (before F7)
to make sure that the message was correctly received. The value of the checksum is
determined by the address and data (or size) of the transmitted exclusive message.
6
How to Calculate the Checksum
(Hexadecimal Numbers are Indicated by ‘H’)
The checksum is a value that produces a lower 7 bits of zero when the address, size,
and checksum itself are summed. If the exclusive message to be transmitted has an
address of aa bb ccH and the data is dd ee ffH, the actual calculation would be as
follows:
aa + bb + cc + dd + ee + ff = sum
sum / 128 = quotient ... remainder
128 - remainder = checksum
(However, the checksum will be 0 if the remainder is 0.)
Setting Dissolve Time Ctrl Assign in MIDI Visual Control to Modulation for Control
Changes
From the “Parameter Address Map,” the start address of the Dissolve Time Ctrl Assign
in MIDI Visual Control is 10H 10H 02H and the Modulation parameter in Control
Change is 00H 01H. Therefore ...
F0H
7EH
00H
0CH 01H
10H 10H 02H
00H 01H
??H
F7H
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(1) Exclusive Status
(2) ID Number (Universal SysEx Non Realtime)
(3) Device ID (0)
(4) Sub ID (MIDI Visual Control Version 1.0)
(5) Address
(6) Data
(7) Checksum
(8) EOX
Next calculate the checksum. Add (5) to (6).
10H + 10H + 02H + 00H + 01H = 16 + 16 + 2 + 0 + 1 = 35 (sum)
35 (sum) / 128 = 0 (quotient) ... 35 (remainder)
Checksum = 128 - 35 (remainder) = 93 = 5DH
Thus, the message to transmit is :
F0H 7EH 00H 0CH 01H 10H 10H 02H 00H 01H 5DH F7H