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PCD5032H

ADPCM CODEC for digital cordless telephones

Philips Electronics 

Philips Semiconductors

ADPCM CODEC for digital cordless

telephones

Product specification

PCD5032

7.1.3 I2C-BUS INTERFACE

The mode of operation and transmitter/receiver gain is

programmed through the I2C-bus serial interface.

The I2C-bus address of the device is shown in Fig.8.

handbook, halfpage

0 0 1 1 0 0 A0 0

(WRITE ONLY)

MGK071

Fig.8 I2C-bus address.

With the address select pin A0 it is possible to have two

independently programmed PCD5032 CODECs in a base

station (two outside lines). If more CODECs are used in a

base station then the address pin can be used as a select

signal. Detailed description of the I2C-bus specification is

given in the brochure “The I2C-bus and how to use it”. This

may be ordered using the code 9398 393 40011.

Each function can be accessed by writing one 8-bit word

to the ADPCM CODEC. For this reason the 8-bit word is

divided into two fields:

• bit 7, bit 6: function

• bit 5 to bit 0: value/setting.

Table 1 gives an overview of the I2C-bus programming

options.

Table 1 Overview of I2C-bus programming options

FUNCTION

Operation mode

Receiver control

Transmitter control

Ringer

BIT 7

0

0

1

1

BIT 6

0

1

0

1

BIT 5

−

RV2

ST1

BF2

BIT 4

−

RV1

ST0

BF1

BIT 3

TONE

RV0

MUTE

BF0

BIT 2

PON

RG2

TG2

BV2

BIT 1

T1

RG1

TG1

BV1

BIT 0

T0

RG0

TG0

BV0

Table 1 definitions:

• TONE: ‘tone/ringer’ section for tone generator output;

tones can be sent to ringer or receiver DAC

• PON: power-on (active)

• T1 and T0: test loops

• RG2 to RG0: receiver gain

• TG2 to TG0: transmitter gain

• RV2 to RV0: receiver volume

• BV2 to BV0: tone volume

• BF2 to BF0: tone frequency

• ST1 to ST0: sidetone level.

Programming the ADPCM CODEC is possible in active

mode as well as in standby mode. A reset clears all

I2C-bus registers.

7.1.4 FAST MUTE

The RFM (Receiver Fast Mute) pin enables fast muting of

the received signal if erroneous data is present on the

ADPCM interface.

Muting is done in the same way as the receiver mute via

the I2C-bus. The input data of the ADPCM decoder is

blanked, so that the ADPCM decoder output signal goes to

zero. To ensure immediate silence on the analog outputs

RE+ and RE−, the linear PCM input data of the receive

filter is set to zero as well.

If the mute signal is switched off again, then the ADPCM

decoder output settles gradually from the zero to the

appropriate PCM signal level. No audible clicks will occur.

The sidetone level is not affected by the mute function.

7.2 Analog parts and I2C-bus programming

7.2.1 INPUT AND OUTPUT

The analog input pins TM+ and TM− can be connected

directly to a microphone. For electret microphones

capacitive coupling is required (see Chapter 12, Fig.13).

The earpiece must be a low-ohmic device (>100 Ω

differential).

The microphone and earpiece amplifiers have the

possibility of gain control via the I2C-bus interface. Further

the sending and receiving direction can be muted

separately. Analog gain control for the receive path can be

set in steps of 1 dB. Digital volume control can be set in

6 dB steps. Table 2 gives an overview of the gain control

options.

1997 Apr 03

10

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