Edirol PC-80 Mode D'emploi page 128

Implémentation MIDI
■System realtime message
●Timing Clock
Status
F8H
* Transmitted if the System setting F8 CLOCK is ON.
●Start
Status
FAH
●Continue
Status
FBH
●Stop
Status
FCH
●Active sensing
Status
FEH
* Transmitted at intervals of approximately 250 ms.
■System exclusive message
❍GM2 System On
Status Data byte
F0H 7EH 7FH 09H 03H
Byte Explanation
F0H Exclusive status
7EH ID number (Universal Non-realtime Message)
7FH Device ID (Broadcast)
09H Sub ID#1 (General MIDI Message)
03H Sub ID#2 (General MIDI 2 On)
F7H EOX (End Of Exclusive)
128
2. Supplementary material
●Decimal and Hexadecimal table
(An "H" is appended to the end of numbers in hexadecimal notation.)
In MIDI documentation, data values are expressed as hexadecimal values for each 7
bits.
The following table shows how these correspond to decimal numbers.
fig.11-22e
Dec.
Status
F7H
* The decimal expression of the MIDI channel, program change, etc., is one greater
than the decimal value shown in the table above.
* The hexadecimal expression for each 7 bits allows a maximum of 128 steps (0–
127) to be expressed by one byte of data. Multiple bytes are used if the data
requires greater resolution than this. For example, a value expressed by two 7-bit
bytes "aa" and "bbH" would be aa x 128 + bb.
* In the case of signed (+/-) data, 00H = -64, 40H = +/-0, and 7FH = +63; i.e., a
value 64 less than the decimal value shown in the above table is used. In the case
of a two-byte value, 00 00H = -8192, 40 00 = +/-0, and 7F 7F = +8191. For
example, a value of "aa" and "bbH" would have a decimal expression of aa bbH
- 40 00H = aa x 128 + bb - 64 x 128.
<Example1>
What is the decimal expression of 5AH?
From the preceding table, 5AH = 90.
<Example2>
What is the decimal expression of the 7-bit hexadecimal value 12 34H?
From the preceding table, 12H = 18, and 34H = 52.
Thus, this is
Hex. Dec. Hex. Dec. Hex.
0 00H 32 20H 64 40H
1 01H 33 21H 65 41H
2 02H 34 22H 66 42H
3 03H 35 23H 67 43H
4 04H 36 24H 68 44H
5 05H 37 25H 69 45H
6 06H 38 26H 70 46H
7 07H 39 27H 71 47H
8 08H 40 28H 72 48H
9 09H 41 29H 73 49H
10 0AH 42 2AH 74 4AH
11 0BH 43 2BH 75 4BH
12 0CH 44 2CH 76 4CH
13 0DH 45 2DH 77 4DH
14 0EH 46 2EH 78 4EH
15 0FH 47 2FH 79 4FH
16 10H 48 30H 80 50H
17 11H 49 31H 81 51H
18 12H 50 32H 82 52H
19 13H 51 33H 83 53H
20 14H 52 34H 84 54H
21 15H 53 35H 85 55H
22 16H 54 36H 86 56H
23 17H 55 37H 87 57H
24 18H 56 38H 88 58H
25 19H 57 39H 89 59H
26 1AH 58 3AH 90 5AH
27 1BH 59 3BH 91 5BH
28 1CH 60 3CH 92 5CH
29 1DH 61 3DH 93 5DH
30 1EH 62 3EH 94 5EH
31 1FH 63 3FH 95 5FH
18 x 128 + 52 = 2356
Dec. Hex.
96 60H
97 61H
98 62H
99 63H
100 64H
101 65H
102 66H
103 67H
104 68H
105 69H
106 6AH
107 6BH
108 6CH
109 6DH
110 6EH
111 6FH
112 70H
113 71H
114 72H
115 73H
116 74H
117 75H
118 76H
119 77H
120 78H
121 79H
122 7AH
123 7BH
124 7CH
125 7DH
126 7EH
127 7FH