TDA7546 datasheet(57/68 Pages) STMICROELECTRONICS

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TDA7546

Software specifications

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The registers are written in the following order:

rds_int[7:0], rds_bd_ctrl[7:0], sinc4reg[7:0], testreg[7:0], pllreg4[7:0], pllreg3[7:0],

pllreg2[7:0], pllreg1[7:0], pllreg0[7:0].

sinc4reg[7:0] and testreg[7:0] are dedicated for test and have to keep zero filled for

application.

Figure 14.

I2C write operation example: write of rds_int and rds_bd_ctrl registers

Read transfer

Figure 15.

I2C read transfer

13 bytes can be read at a time (please refer to the to the relevant sectionsfor the meaning of

each bit).

The master has the possibility to read less than 13 registers by not sending the

acknowledge bit and then generating a stop condition after having read the needed amount

of registers.

There are two typical read access:

–

read only the first register rds_int to check the interrupt bit.

–

read the first five registers rds_int, rds_qu, rds_corrp, rds_bd_h and rds_bd_l to

get the RDS data.

The registers are read in the following order:

rds_int[7:0], rds_qu[7:0], rds_corrp[7:0], rds_bd_h[7:0], rds_bd_l[7:0], rds_bd_ctrl[7:0],

sinc4reg[7:0], testreg[7:0], pllreg4[7:0], pllreg3[7:0], pllreg2[7:0], pllreg1[7:0], pllreg0[7:0].

Only the “bne” flag can be used for polling mode. There are two different ways to use this

mode, while the first one causes less bus traffic than the second:

Read only the first register rds_int to check the “bne” bit.

If “bne” bit is not set, the stop condition can be set, as shown in (Figure 17).

SDA

SCL

START

CONDITION

ACK

rds_int[7:0]

rds_bd_ctrl[7:0]

STOP

CONDITION

ACK

CSN 1

SLAVE ADDRESS

Slave address

rds_int

rds_qu

testreg

from master to slave

from slave to master

S = start condition

Slave address = 001000S ( where S is the level of the pin

SA_DATAOUT)

A = acknowledge bit

P = stop condition

R = read mode

TDA7546 Datasheet(PDF) 57 Page - STMicroelectronics

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