Roland PCR-80 - Manual (Page 177)

177
MIDI implementation
3. Bulk dump
Bulk dump allows a large amount of data to be transferred in a single operation.
For example, this can be used to store all settings of a device into a computer or
sequencer.
On the PCR-30/50/80, a bulk dump will be transmitted when you execute the Bulk
mode operation BULK TX. The bulk dump is transmitted as several exclusive
messages.
Address Parameter Packets
00H, 00H, 00H, 00H--00H, 00H, 1A, 7F Current memory 27
* You must leave an interval of at least 40 ms between each exclusive message.
* In the case of ALL BULK, the contents of memories 1--F will be transmitted as
the current memory, consecutively from memory 1 through memory F. After
transmitting one set of bulk dump data, you must leave an interval of at least
500 ms.
* Please be aware that if you modify the data dumped from the PCR-30/50/80 by
changing the order in which the exclusive messages are transmitted, by
inserting other messages between the system exclusive messages, or by
speeding up the timing of the transmission, the data may not be set correctly
when the PCR-30/50/80 receives it.
4. Supplementary material
● Decimal and Hexadecimal table
(An “H” is appended to the end of numbers in hexadecimal notation.)
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.
fig.11-22e
* 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.
* In the case of data indicated as “use nibble data,” hexadecimal expression in 4-
bit units is used. A nibble-expressed value of the two bytes 0a and 0bH would
have a 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 7-bit hexadecimal value 12 34H?
From the preceding table, 12H = 18, and 34H = 52.
Thus, this is
18 x 128 + 52 = 2356
What is the decimal expression of the nibble-expressed value 0A 03 09 0D?
From the preceding table, 0AH = 10, 03H = 3, 09H = 9, and 0DH = 13.
Thus, this is
((10 x 16 + 3) x 16 + 9) x 16 + 13 = 41885
What is the nibble-expressed value of decimal 1258?
1258 ÷ 16 = 78 (quotient) ... 10 (remainder)
78 ÷ 16 = 4 (quotient) ... 14 (remainder)
4 ÷ 16 = 0 (quotient) ... 4 (remainder)
From the preceding table, 0 = 00H, 4 = 04H, 14 = 0EH, 10 = 0HA.
Thus, the nibble-expressed value is
00 04 0E 0AH
● Example of an actual MIDI message
CE 04
CnH is the Program Change status. “n” is the MIDI channel number. EH = 14, and
04H = 04. Thus, this is a program change message on MIDI channel 15, for program
number 05.
● Checksum calculation
In order to verify that the message was received correctly, Roland exclusive
messages (RQ1, DT1) add a checksum following the end of the data (before the F7).
The checksum value is determined by the address and data (or size) of the
exclusive message that is transmitted.
❍ Calculating the checksum
(“H” has been added following hexadecimal values)
The checksum is a value that results in a lower 7 bits of 0 when the address, size,
and checksum itself are added together.
Specifically, the calculation will be as follows when the exclusive message you
want to transmit has an address of aa bb ccH and data or size of dd ee ffH.
aa + bb + cc + dd + ee + ff = total
total ÷ 128 = quotient ... remainder
128 - remainder = checksum
* However, as an exception, the checksum for a remainder of 0 is not 80H but
rather 00H.
Dec. Hex. Dec. Hex. Dec. Hex. Dec. Hex.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
00H
01H
02H
03H
04H
05H
06H
07H
08H
09H
0AH
0BH
0CH
0DH
0EH
0FH
10H
11H
12H
13H
14H
15H
16H
17H
18H
19H
1AH
1BH
1CH
1DH
1EH
1FH
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63 20H
21H
22H
23H
24H
25H
26H
27H
28H
29H
2AH
2BH
2CH
2DH
2EH
2FH
30H
31H
32H
33H
34H
35H
36H
37H
38H
39H
3AH
3BH
3CH
3DH
3EH
3FH
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95 40H
41H
42H
43H
44H
45H
46H
47H
48H
49H
4AH
4BH
4CH
4DH
4EH
4FH
50H
51H
52H
53H
54H
55H
56H
57H
58H
59H
5AH
5BH
5CH
5DH
5EH
5FH
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
60H
61H
62H
63H
64H
65H
66H
67H
68H
69H
6AH
6BH
6CH
6DH
6EH
6FH
70H
71H
72H
73H
74H
75H
76H
77H
78H
79H
7AH
7BH
7CH
7DH
7EH
7FH