DJM-700-S
101
5
6
7
8
5
6
7
8
C
D
F
A
B
E
Confirmation of microcomputer
operation
MAIN ASSY
IC1101 (DYW1761-A/J)
D
1/4
MAIN ASSY
IC1205 (DYW1760-A/J)
D
1/4
Pin No
Voltage(V)
Pin No
Voltage(V)
Pin No
Voltage(V)
Pin No
Voltage(V)
1
0.27
51
0
1
0
51
0
2
0
52
1.61
2
0
52
0
3
0
53
1.61
3
0
53
0
4
0
54
2.01
4
0
54
0
5
0 (
∗
)
55
1.62
5
0 (
∗
)
55
0
6
3.16
56
0
6
3.22
56
1.48
7
3.16
57
0
7
3.22
57
1.76
8
3.16
58
0
8
3.22
58
1.76
9
0
59
0
9
0
0
59
10
0
0
60
10
0
0
60
11
0
61
0.42
11
0
61
0
12
0
62
0.42
12
0
62
0
13
0
63
0.42
13
0
63
0
14
0
64
0.42
14
0
64
0
15
0
65
0.42
15
0
65
0
16
0.3
66
0.42
16
0
66
0
17
0
67
0.42
17
0
67
0
18
3.17
68
0.37
18
3.23
68
3.19
19
1.52
69
3.24
19
1.59
69
0
20
0
70
3.24
20
0
70
3.21
21
0
71
0
21
1.02
71
0
22
0.22
72
0
22
1.01
72
3.19
23
0.22
73
1.6
23
1.03
73
0
24
0
74
1.6
24
1.06
74
3.21
25
0
75
0
25
1.03
75
0
26
0.21
76
0
26
1.06
76
0
27
0
77
0.36
27
1.03
77
3.21
28
0.21
78
0
28
1.01
78
3.21
29
0
79
0.36
29
1.61
79
3.19
30
3.16
80
0.37
30
3.24
80
0
31
0
81
0
31
1.01
81
3.15
32
0
82
0
32
1.1
82
3.18
33
0.21
83
0.16
33
0
83
3.16
34
0.21
84
0.94
34
0
84
0
35
0
85
0
35
0
85
3.17
36
0
86
3.05
36
0
86
3.18
37
0
87
3.22
37
0
87
0
38
0
88
3.23
38
2
88
0
39
0
89
3.23
39
3.24
89
0
40
0
90
3.23
40
0
90
3.18
41
0
91
0
41
0
91
42
0
92
0
42
0
0
0
92
43
0
93
0
43
3.22
93
0
44
0
94
1.54
44
0
94
1.5
45
0
95
0.03
45
0.01
95
0
46
0
96
2.43
46
3.24
96
2.38
47
3.11
97
0
47
3.22
97
0
48
3.16
98
0
48
1.57
98
0
49
3.16
99
3.23
49
1.57
99
3.18
50
3.11
100
3.23
50
3.22
100
3.18
• If the level is low (less than 1 V), the microcomputers are operating
on the external clock (X'tal). (OK)
• If the level is high (3.3 V), the microcomputers are operating on the
internal clock. (NG)
Although the microcomputers normally operate on the external
clock (X'tal), they may operate on the internal clock. In such a case,
performance cannot be guaranteed. Whether the microcomputers
are operating on the external or internal clock can be detected by
checking whether the output from Pin 5 of IC1101 or IC1205 is low
or high.
Overview:
The purpose is to check if the 20-MHz clock is input to the
microcomputers IC1101 and IC1205 from the X'tal and if they
operate properly with that clock.
Description:
For the microcomputers IC1101 and IC1205 of this unit, users can
select whether the internal clock from the built-in oscillation circuit
or the external clock is to be used after initialization of the unit.
After the first startup and reset is canceled, the unit operates on
the internal clock from the built-in high-speed oscillation circuit
(default setting: 4 MHz) until user setting is made. By so doing, the
microcomputers can continue operation with the internal clock if
signals from the external clock are not supplied for any reason.
The discrepancy in clock frequencies, which is not apparent
visually, may be detected with the following phenomena, because
the discrepancy in clock frequencies results in a discrepancy in
processing speed:
Main microcomputer:
Discrepancy in the MIDI timing clock
Sub-microcomputer:
Discrepancy in frequencies of LED's lighting/flashing
Discrepancy in frequencies of FL's flashing
How to judge:
The microcomputers IC1101 and IC1205 can detect whether the
clock on which they are operating is internal or external, by
referring to the value of an internal register. After initialization is
completed, they refer to that value and judge whether or not they
are operating on the external clock then output the result (low or
high) from the specified terminal.
Note:
Only whether the operating clock is external or internal can be
judged by the microcomputers. They cannot judge whether the
frequency of the external clock is 20 MHz or not. If a clock whose
frequency is not 20 MHz is supplied, the microcomputers operate
on that clock.
Terminal from which the result is output: Pin 5 (IC1101 and IC1205)
Status of terminal Result Remarks
(voltage)
Low
OK
The microcomputers are operating on
the 20-MHz external clock (X'tal).
High
NG
The microcomputers are operating on
the
internal
clock.
VOLTAGES