Chapter 4: Programming
4-9
Configurable Key Click Tone
The
FPGA
has
the
ability
to
sound
a
short
chirp
whenever
a
key
is
pressed,
providing
auditory
feedback
to
an
operator
of
the
keyboard.
This
auditory
feedback
is
optional.
The
FPGA
may
be
configured
to
make
the
sound
or
not
to
make
the
sound,
depending
on
the
particular
application.
USB DynaKey Tone Frequencies
The
frequency
is
transmitted
to
the
FPGA
as
a
Note
Number
.
Note
numbers
are
equivalent
to
specific
frequencies.
The
note
number
sent
to
the
FPGA
is
selected
by
rounding
the
requested
frequency
to
the
nearest
frequency
number
given
by
the
table
of
Note
Numbers
(
N
)
and
Frequencies
(
freq
)
listed
in
the
following
table.
Note
Numbers
and
Frequencies
Note N
freq N freq N freq N freq N freq N freq
A
0
28
24
110
48
440
72
1760
96
7040
120
28160
Bb
1
29
25
117
49
466
73
1865
97
7459
121
29834
B
2
31
26
123
50
494
74
1976
98
7902
122
31609
C
3
33
27
131
51
523
75
2093
99
8372
123
33488
Db
4
35
28
139
52
554
76
2217
100
8870
124
35479
D
5
37
29
147
53
587
77
2349
101
9397
125
37589
Eb
6
39
30
156
54
622
78
2489
102
9956
126
39824
E
7
41
31
165
55
659
79
2637
103
10548
127
42192
F
8
44
32
175
56
698
80
2794
104
11175
Gb
9
46
33
185
57
740
81
2960
105
11840
G
10
49
34
196
58
784
82
3136
106
12544
Ab
11
52
35
208
59
831
83
3322
107
13290
A
12
55
36
220
60
880
84
3520
108
14080