TDA7529_11 Datasheet, PDF (17/61 Pages) STMicroelectronics – RF front-end for AM/FM DSP car-radio with IF sampling

TDA7529
Function description
3.11
AFSAMPLE/AFHOLD
On the TDA7529 there are two dedicated open drain pins (AFSAMPLE and AFHOLD), that
allow the control of the DSP (mute and quality controls) during AF update.
Details are given in Chapter 5.
3.12
Serial bus interface
The TDA7529 has a serial data port for communication with the microcontroller. It is used for
programming the device and for reading out its detectors. This port supports data
communication using the SPI and the I²C protocol. The data transfer of several consecutive
bytes is supported by the auto increment feature.
Table 6. Supports data communication using the SPI and the I²C protocol
Name
Pin
SPI signal
Pin
I²C signal
Signal 1
PS Protocol Select SPI/I²C
PS Protocol Select SPI/I²C
Signal 2
CS Chip Select
AS Address Select
Signal 3
CLK Clock
CLK Clock
Signal 4
MOSI Master Out – Slave In
DATA bidirectional Data
Signal 5
MISO Master In – Slave Out
GP6 General Purpose Out
The "PS"- pin (protocol select) determines which communication protocol is used. The
information is not latched, so any level change at this pin immediately affects the protocol
used by the TDA7529.
The SPI protocol is selected by setting PS = 0 while, during the I²C operation, PS needs to
be open (internally set to 1).
SPI-Protocol: CPOL=1, CPHA=1.
The CS pin performs the Chip Select function during the SPI operation; it has to be reset to
0 during transmission or reception, otherwise set to 1 (the CS pin is set to 1 by leaving it
open).
Both the CS and the AS functions are performed by the CS pin.
When the I²C mode is used, the "AS" pin determines which I²C address or group of
addresses (see below) is used. Three different external connections are defined to
represent three groups of addresses (refer to the following table for details). The information
is not latched, so any level change at this pin immediately affects the address used by the
TDA7529.
First the IC address is transmitted including the R/W bit for setting the direction of the
following data transfer
Doc ID 13311 Rev 4
17/61