PCD3755AH Просмотр технического описания (PDF) - Philips Electronics

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PCD3755AH

8-bit microcontrollers with DTMF generator, 8 kbytes OTP and 128 bytes EEPROM

Philips Electronics 

Philips Semiconductors

8-bit microcontrollers with DTMF generator,

8 kbytes OTP and 128 bytes EEPROM

Product specification

PCD3755A; PCD3755E;

PCD3755F

6.4 DTMF frequencies

Assuming an oscillator frequency fxtal = 3.58 MHz, the

DTMF standard frequencies can be implemented as

shown in Table 6.

The relationships between telephone keyboard symbols,

DTMF frequency pairs and the frequency register contents

are given in Table 7.

Table 6 DTMF standard frequencies and their

implementation; value = LGF, HGF contents

VALUE

FREQUENCY (Hz)

DEVIATION

(HEX) STANDARD GENERATED (%) (Hz)

DD

697

697.90

0.13 0.90

C8

770

770.46

0.06 0.46

B5

852

850.45

−0.18 −1.55

A3

941

943.23

0.24 2.23

7F

1 209

1 206.45

−0.21 −2.55

72

1 336

1 341.66

0.42 5.66

67

1 477

1 482.21

0.35 5.21

5D

1 633

1 638.24

0.32 5.24

Table 7 Dialling symbols, corresponding DTMF

frequency pairs and frequency register contents

TELEPHONE DTMF FREQ.

KEYBOARD PAIRS

SYMBOLS

(Hz)

0

(941, 1336)

1

(697, 1209)

2

(697, 1336)

3

(697, 1477)

4

(770, 1209)

5

(770, 1336)

6

(770, 1477)

7

(852, 1209)

8

(852, 1336)

9

(852, 1477)

A

(697, 1633)

B

(770, 1633)

C

(852, 1633)

D

(941, 1633)

•

(941, 1209)

#

(941, 1477)

LGF

VALUE

(HEX)

A3

DD

DD

DD

C8

C8

C8

B5

B5

B5

DD

C8

B5

A3

A3

A3

HGF

VALUE

(HEX)

72

7F

72

67

7F

72

67

7F

72

67

5D

5D

5D

5D

7F

67

6.5 Modem frequencies

Again assuming an oscillator frequency fxtal = 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

HGF

VALUE

(HEX)

9D

82

8F

79

80

45

76

48

5C

52

4B

44

FREQUENCY (Hz)

MODEM

980(1)

1 180(1)

1 070(2)

1 270(2)

1 200(3)

2 200(3)

1 300(4)

2 100(4)

1 650(1)

1 850(1)

2 025(2)

2 225(2)

GENERATED

978.82

1 179.03

1 073.33

1 265.30

1 197.17

2 192.01

1 296.94

2 103.14

1 655.66

1 852.77

2 021.20

2 223.32

DEVIATION

(%) (Hz)

−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

Notes

1. Standard is V.21.

2. Standard is Bell 103.

3. Standard is Bell 202.

4. Standard is V.23.

1997 Apr 16

10

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