1999 Oct 28
11
Philips Semiconductors
Product specification
8-bit microcontrollers with DTMF generator
and 128 bytes EEPROM
PCA3351C; 52C; 53C;
PCD3351A; 52A; 53A
6.5
Modem frequencies
Again assuming an oscillator frequency f
xtal
= 3.58 MHz,
the standard modem frequencies can be implemented as
in Table 9. It is suggested to define the frequency by the
HGF register while the LGF register contains 00H,
disabling Low Group Frequency generation.
Table 9
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.
6.6
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 10). It is suggested to define the
frequency by the HGF register while the LGF contains
00H, disabling Low Group Frequency generation
Table 10
Musical scale frequencies and their
implementation
Note
1.
Standard scale based on A4 @ 440 Hz.
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
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