SAA7284ZP データシートの表示（PDF） - Philips Electronics

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SAA7284ZP

Terrestrial digital sound decoder for conventional intercarrier PLL-IF systems

Philips Electronics 

Philips Semiconductors

Terrestrial digital sound decoder for

conventional intercarrier PLL-IF systems

Preliminary specification

SAA7284

I2C-bus slave receiver register map

Table 4 Slave receiver data byte

SUB-ADDRESS

D7

D6

000

M1/M2 DMSEL

001

EMAX7 EMAX6

010

EMIN7 EMIN6

011

C4OV

MUTE

100

ASYS

BG/I

D5

SSWIT3

EMAX5

EMIN5

SILENCE

NICLEV

D4

SSWIT2

EMAX4

EMIN4

DAIE

STLOCK

D3

SSWIT1

EMAX3

EMIN3

FM3

−

D2

PORT2

EMAX2

EMIN2

FM2

−

D1

MUTEDEF

EMAX1

EMIN1

FM1

−

D0

AMDIS

EMAX0

EMIN0

FM0

−

M1/M2

This bit selects either mono channel M1 or M2 to be the

output on the left and right channel dependent on the

transmitted control bits C1 and C2 indicating a mono

transmission and the value of bit DMSEL (see Table 5).

Power-on resets to logic 1.

DMSEL

DMSEL is the dual mono selection bit, for transmissions

consisting of two independent mono signals. Selection is

in conjunction with M1/M2 (see Table 5). Power on resets

to logic 0.

SSWIT1, SSWIT2 AND SSWIT3

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 7. Power-on resets to 010 with PORA

pin HIGH, and to 011 with PORA pin LOW.

PORT2

PORT2 controls a bit out, providing direct access to a

dedicated output pin (PORT2) via the I2C-bus.

See Table 6. Power-on resets to logic 0.

MUTEDEF

This defines the operation of the user definable MUTE pin

or MUTE I2C-bus bit when it is pulled LOW externally or set

LOW in the I2C-bus respectively.

When this bit is HIGH, pulling the MUTE pin/I2C-bus bit

LOW will mute (set to zero) the digital data and switch the

output to the FM input, depending on relevant control bits

(see Table 8). When this bit is LOW, pulling the MUTE

pin/I2C-bus bit LOW will only mute the digital data under

the same conditions. Power-on resets to LOW.

AMDIS

This bit enables and disables the automatic mute function.

Power-on resets to enabled = LOW.

EMAX7 TO EMAX0

This is the upper error limit register which defines the

number of errors in 128 ms period which will cause

automatic mute to switch IN. User definable, but power-on

resets to 50 (HEX).

EMIN7 TO EMIN0

This is the lower error limit register which defines the

number of errors in 128 ms period which will cause

automatic mute to switch OUT. User definable, but

power-on resets to 14 (HEX).

C4OV

When set LOW this bit overrides the status of the

transmitted C4-bit when muting. When this bit is HIGH

muting takes place in accordance with EBU specification.

Power-on resets to HIGH when the PORA pin is held LOW

during power-up, and power-on resets to LOW when

PORA is HIGH.

MUTE

This reflects the function of the MUTEB pin. When this bit

is set LOW the external MUTEB pin is pulled LOW and the

action is dependent on the MUTEDEF bit (see Table 8).

Power-on resets to HIGH.

SILENCE

When set LOW this bit silences the outputs of the device

by switching the input of the audio switching buffers to

analog ground. When the PORM pin is held LOW at

power-on reset the silence bit is initialized to zero.

With PORM bit HIGH the silence bit is initialized HIGH.

1996 Oct 24

13

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