July 1993

7

Philips Semiconductors

Product specification

Terrestrial Digital Sound Decoder (TDSD2)

SAA7282

• Read decoder status information derived from the transmitted digital audio signal

• Read an error count byte to determine the bit error rate for user mute purposes and to indicate quality of NICAM signal

• Read additional transmitted data bits. Their purpose has yet to be defined but accessibility is provided to allow future

services to be implemented in receiver software

• Write control codes to select the available analog switching configurations

• Write upper and lower error count limits for automatic muting function

The device slave address is A(7:1)(R/W) = 101101X(R/W). An ADSEL pin is provided to allow selection of one of two

different slave addresses via programmable address bit A1. (X = ADSEL logic level).

The slave receiver format is:

S SLAVE_ADDR.0 ACK SUB_ADDR ACK DATA BYTE ACK P

<−n bytes−>

Where S = start, ACK = acknowledge, P = stop.

Auto-increment of the sub-address is provided with wrap-around from 02 (HEX) to 00 (HEX).

The slave receiver data byte format, as a function of sub-address, is as shown in Table 1.

Table 1

Slave receiver data byte.

M1/M2

This bit in conjunction with DMSEL bit, determines the output configuration in dual mono mode (see Table 2).

Power-on resets to logic 1.

DMSEL

This bit determines whether one or both of the dual mono signals are output (see Table 2). Power-on resets to logic 0.

PORT2

Power-on resets to logic 0.

SSWIT3/2/1

These bits control the analog switching, selecting between the FM, external, and NICAM signals. With the NICAM source

the signals select whether the de-emphasis is performed and what gain is applied after the filtering and de-emphasis

stage. The signal states and their meaning are listed in Table 4. Power-on resets to 0/1/0.

SUB-

ADDRESS

RESET

VALUE

HEX

D7

D6

D5

D4

D3

D2

D1

D0

00

90

M1/M2

DMSEL

SSWIT3

SSWIT2

SSWIT1

PORT2

MUTEDEF

AMDIS

01

50

EMAX7

EMAX6

EMAX5

EMAX4

EMAX3

EMAX2

EMAX1

EMAX0

10

14

EMIN7

EMIN6

EMIN5

EMIN4

EMIN3

EMIN2

EMIN1

EMIN0