1996 Nov 21

7

Philips Semiconductors

Product specification

DTMF/modem/musical-tone generators

PCD3311C; PCD3312C

Fig.5

Timing of STROBE, parallel data inputs and TONE output (770 Hz + 1477 Hz in example) in the parallel

mode (MODE = HIGH).

handbook, full pagewidth

MGG511

tSPW

tDS

tDH

90%

10%

oscillator ON

no output tone

oscillator ON

output tones

oscillator OFF

ttone (ON)

STROBE

D0

D1

D2

D3

D4

D5

TONE

7.6

SCL and SDA are the serial clock and serial data inputs

For the PCD3311C, SCL and SDA are combined with

parallel inputs D0 and D1 respectively - D0/SCL and

D1/SDA operate serially only when MODE is LOW.

7.7

Address input

Address input A0 defines the least significant bit of the

of the address are fixed internally. By tying the A0 of each

different PCD3311C or PCD3312C devices can be

individually addressed on the bus.

Whether one or two devices are used, A0 must be

7.8

The PCD3311C and PCD3312C are always slave

thus always LOW, indicating that the master

(microcontroller) is writing.

The slave address in the serial mode consists of 7 bits: 6

bits internally fixed, 1 externally set via A0. in the serial

mode, the same input data codes are used as in the

parallel mode. See Tables 2, 3, 4 and 5.

7.9

Tone output

The single and dual tones provided at the TONE output are

first filtered by an on-chip switched-capacitor filter,

followed by an active RC low-pass filter. The filtered tones

fulfil the CEPT recommendations for total harmonic

distortion of DTMF tones. An on-chip reference voltage

provides output tone levels independent of the supply

voltage. Tables 3, 4 and 5 give the frequency deviation of

the output tones with respect to the standard DTMF,

modem and music frequencies.