1998 May 11

6

Philips Semiconductors

Product specification

8-bit microcontroller with DTMF generator

PCD3349A

6

FREQUENCY GENERATOR

A versatile frequency generator section is provided (see

Fig.3). For normal operation, use a 3.58 MHz quartz

crystal or PXE resonator. The frequency generator

includes precision circuitry for dual tone multifrequency

(DTMF) signals, which is typically used for tone dialling

telephone sets.

The TONE output can alternatively issue twelve modem

frequencies for data rates between 300 and 1200 bits/s.

In addition to DTMF and modem frequencies, two octaves

of musical scale in steps of semitones are available.

6.1

Frequency generator derivative registers

Table 2 gives the derivative addresses, mnemonics and access types of the frequency generator derivative registers.

The addresses 03H to FFH are not used.

Table 2

Addresses of the frequency generator derivative registers

Notes

1. HGF = High Group Frequency; access type W.

2. LGF = Low Group Frequency; access type W.

ADDRESS

REGISTER

7

6

5

4

3

2

1

0

01H

H7

H6

H5

H4

H3

H2

H1

H0

02H

L7

L6

L5

L4

L3

L2

L1

L0

Fig.3 Block diagram of the frequency generator section.

dbook, full pagewidth

HGF

REGISTER

MBG099

DIGITAL

SINE WAVE

SYNTHESIZER

8

SWITCHED-

CAPACITOR

BANDGAP

VOLTAGE

REFERENCE

DAC

DAC

LGF

REGISTER

DIGITAL

SINE WAVE

SYNTHESIZER

8

8 internal bus

SWITCHED-

CAPACITOR

LOW-PASS FILTER

RC LOW-PASS

FILTER

TONE