TDA7404D

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The External AC - Coupling is selected in position of four switches controlled by the lower 2bit in the Others

selection. (See table)

Others selection

1.10 Speaker Attenuator

Due to practical aspects the steps in the speaker-attenuators are not linear over the full range. At attenuations

more than 24dB the steps increase from 1.5dB to 10dB (please see data byte specification).

1.11 Subwoofer Attenuator

The Subwoofer output is a single ended stereo output. The attenuator is exactly the same like the other speak-

ers.

2.1 Interface Protocol

The interface protocol comprises:

s

a start condition (S)

s

a chip address byte (the LSB bit determines read / write transmission)

s

a subaddress byte

s

a sequence of data (N-bytes + acknowledge)

s

a stop condition (P)

s

the max. CLOCK SPEED is 500kbits/s

S = Start

R/W ="0" -> Receive-Mode (Chip could be programmed by P)

"1" -> Transmission-Mode (Data could be received by P)

ACK = Acknowledge

P = Stop

2.2 TRANSMITTED DATA (send mode)

SM = Soft mute activated

X = Not Used

The transmitted data is automatic updated after each ACK. Transmission can be repeated without new chipaddress.

D1

D0

Switch position

X

0

SW3 = ON , SW4 = ON (selected internal pass), SW1 = b , SW2 = open

0

1

SW3 = OFF , SW4 = ON, SW1 = a , SW2 = a

1

1

SW3 = ON , SW4 = OFF, SW1 = b , SW2 = b

MSB

LSB

XX

X

X

X

X

X

SM

S

1

0

0

0

1

0

0

R/W

ACK

ACK

ACK

ACK

P

MSB

LSB

MSB

LSB

MSB

LSB

CHIP ADDRESS

D99AU1044

I3

I0

SUBADDRESS

DATA 1 to DATA n

I2 I1

A3 A2 A1 A0