
1996 Dec 18
10
Philips Semiconductors
Product specification
8-bit microcontrollers with DTMF
generator and 256 bytes EEPROM
PCA3354C; PCD3354A
6.6
Modem frequencies
Again assuming an oscillator frequency f
xtal
= 3.58 MHz,
the standard modem frequencies can be implemented as
in Table 8. It is suggested to define the frequency by the
HGF register while the LGF register contains 00H,
disabling Low Group Frequency generation.
Table 8
Standard modem frequencies and their
implementation
Notes
1.
2.
3.
4.
Standard is V.21.
Standard is Bell 103.
Standard is Bell 202.
Standard is V.23.
6.7
Musical scale frequencies
Finally, two octaves of musical scale in steps of semitones
can be realized, again assuming an oscillator frequency
f
xtal
= 3.58 MHz (Table 9). It is suggested to define the
frequency by the HGF register while the LGF contains
00H, disabling Low Group Frequency generation.
HGF
VALUE
(HEX)
FREQUENCY (Hz)
DEVIATION
MODEM
GENERATED
(%)
(Hz)
9D
82
8F
79
80
45
76
48
5C
52
4B
44
980
(1)
1180
(1)
1070
(2)
1270
(2)
1200
(3)
2200
(3)
1300
(4)
2100
(4)
1650
(1)
1850
(1)
2025
(2)
2225
(2)
978.82
1179.03
1073.33
1265.30
1197.17
2192.01
1296.94
2103.14
1655.66
1852.77
2021.20
2223.32
0.12
0.08
0.31
0.37
0.24
0.36
0.24
0.15
0.34
0.15
0.19
0.08
1.18
0.97
3.33
4.70
2.83
7.99
3.06
3.14
5.66
2.77
3.80
1.68
Table 9
Musical scale frequencies and their
implementation
Note
1.
Standard scale based on A4 @ 440 Hz.
NOTE
HGF
VALUE
(HEX)
FREQUENCY (Hz)
STANDARD
(1)
GENERATED
D#5
E5
F5
F#5
G5
G#5
A5
A#5
B5
C6
C#6
D6
D#6
E6
F6
F#6
G6
G#6
A6
A#6
B6
C7
C#7
D7
D#7
F8
EA
DD
D0
C5
B9
AF
A5
9C
93
8A
82
7B
74
6D
67
61
5C
56
51
4D
48
44
40
3D
622.3
659.3
698.5
740.0
784.0
830.6
880.0
923.3
987.8
1046.5
1108.7
1174.7
1244.5
1318.5
1396.9
1480.0
1568.0
1661.2
1760.0
1864.7
1975.5
2093.0
2217.5
2349.3
2489.0
622.5
659.5
697.9
741.1
782.1
832.3
879.3
931.9
985.0
1044.5
1111.7
1179.0
1245.1
1318.9
1402.1
1482.2
1572.0
1655.7
1768.5
1875.1
1970.0
2103.3
2223.3
2358.1
2470.4