SOFTWARE SPECIFICATIONS

The TDA7476 is activated by turning-on the ST-BY pin (CMOS compatible). In this condition it waits for

the I

ADD1

S

010001A

0

ACK

P

This sequence (where the bit 0 of ADD1 is at 0 level) enables the acquisition routine and starts the single

pulse (containing infrasonic harmonics) for the test. During this period the data regarding all the outputs

are memorized.

After a period Twait1 that depends on the value of the timing capacitor (see Timing) the

µP redirects the

TDA7476 by the byte ADD2.

ADD2

S

010001A

1

ACK

BYTE 1

ACK

BYTE 2

ACK

BYTE 3

ACK

STOP

The byte ADD2 contains the bit 0 at 1 level. This enables the reading mode, TDA7476’s. The 3 bytes

with the diagnostic information BYTE1, BYTE2, BYTE3 (READ FROM TDA7476) are now transmitted to

the

µP.

The address of TDA7476 is selected using pin ADD (pin 4) .

If ADD is connected to ground, then A = 0 and the TDA7476 address is 0100010X.

If ADD is connected to 5V, than A = 1 and the TDA7476 address is 0100011X

The TDA7476 provides two types of diagnostic information:

A) TURN-ON DIAGNOSTIC - The first time that the TDA7476 is addressed by I

plete set of diagnostic information is activated:

- CH1, CH2, CH3, CH4, CH5

Short Circuit to GND

Short Circuit to Vs

Open Load (*)

Short Circuit across the load (*)

(*) Detected if the power amplifiers are in ST-BY condition.

- AUX1, AUX2

Short Circuit to GND (*)

Open Load (*)

(*) Detected if the high side drivers attached to the Aux outputs are ON.

Here following the turn-on diagnostic output bytes

TDA7476

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