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TDA7438

5

SOFTWARE SPECIFICATION

Interface Protocol

The interface protocol comprises:

■

A start condition (S)

■

A chip address byte, containing the TDA7438 address

■

A subaddress bytes

■

A sequence of data (N byte + acknowledge)

Figure 16.

ACK = Acknowledge

S = Start

P = Stop

A = Address

B = Auto Increment

5.1 EXAMPLES

5.1.1 No Incremental Bus

The TDA7438 receives a start condition, the correct chip address, a subaddress with the B = 0 (no incre-

mental bus), N-data (all these data concern the subaddress selected), a stop condition.

Figure 17.

5.1.2 Incremental Bus

The TDA7438 receive a start conditions, the correct chip address, a subaddress with the B = 1 (incremen-

tal bus): now it is in a loop condition with an autoincrease of the subaddress whereas SUBADDRESS from

"XXX1000" to "XXX1111" of DATA are ignored.The DATA 1 concern the subaddress sent, and the DATA

2 concern the subaddress sent plus one in the loop etc, and at the end it receivers the stop condition

SCL

1

MSB

23789

SDA

START

ACKNOWLEDGMENT

FROM RECEIVER

D99AU1033

S

1

0

0

0

1

0

0

0

ACK

ACK

DATA

ACK

P

MSB

LSB

MSB

LSB

MSB

LSB

CHIP ADDRESS

D96AU420

X

DATA

SUBADDRESS

DATA 1 to DATA n

X

X

B

S

1

0

0

0

1

0

0

0

ACK

ACK

DATA

ACK

P

MSB

LSB

MSB

LSB

MSB

LSB

CHIP ADDRESS

D96AU421

X

D3

SUBADDRESS

DATA

X

X

0

D2 D1 D0