TDA7476

10/19

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The minimum voltage of the AUX IN pins to sense the open load condition is 2V.

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The minimum voltage of the AUX IN pin to detect the short circuit to GND by sensing drop on the resistor

is 4.5V. If this voltage is below 2V, the AUX line is considered short circuited to GND. From 2V to 4.5V

the sensing circuit can detect a short circuit in both ways (by sensing across the resistor or through the

voltage between the AUX IN pin and GND).

interface, consisting of the two lines SDA and SCL (pull-up resistors to positive supply voltage must be connected).

Data Validity

As shown by fig. 2, the data on the SDA line must be stable during the high period of the clock. The HIGH and

LOW state of the data line can only change when the clock signal on the SCL line is LOW.

Start and Stop Conditions

As shown by fig. 3 a start condition is a HIGH to LOW transition of the SDA line while SCL is HIGH. The stop

condition is a LOW to HIGH transition of the SDA line while SCL is HIGH.

Byte Format

Every byte transferred to the SDA line must contain 8 bits. Each byte must be followed by an acknowledge bit.

The MSB is transferred first.

Acknowledge

The transmitter* puts a resistive HIGH level on the SDA line during the acknowledge clock pulse (see fig.4). The

receiver** the acknowledges has to pull-down (LOW) the SDA line during the acknowledge clock pulse, so that

the SDAline is stable LOW during this clock pulse.

* Transmitter

= master (

µP) when it writes an address to the TDA7476

= slave (TDA7476) when the

µP reads a data byte from TDA7476

** Receiver

= slave (TDA7476) when the

µP writes an address to the TDA7476

= master (

µP) when it reads a data byte from TDA7476

SDA

SCL

DATA LINE

STABLE, DATA

VALID

CHANGE

DATA

ALLOWED

D99AU1031