TDA7505

Software features

35/38

6.7

Other

●

Voice compression/decompression for traffic information storage

●

Echo and noise canceling for mobile phone connection

6.8

Functional modes

The SW defines the whole functionality of the device, except RDS. Although ST is able to

provide a complete set of SW, the customer may implement his own SW or may use third

party SW. This allows a flexible adaptation to the application needs.

The concept allows the parallel processing of two independent audio sources. For example

one source may go through the loudspeakers, whereas another source may feed a

headphone. Additionally other sources like a phone or a navigation system may be mixed to

the audio source. In case the 150 MIPS available are not sufficient, a co-dsp (e.g.:

TDA7502) may be connected through the serial audio interface (SAI). Finally the device may

be embedded into an audio bus system (e.g.: MOST).

Following table shows an example of possible modes:

Note:

The main source (blue) may run in parallel with one of the alternative rear sources (yellow).

Phone/Navi, DSP Co-processor, traffic info storage and MOST (green) are available in

parallel to all modes.

Table 29.

Example of possible modes

Source

Comment

AM/FM mode

CD mode

(digital)

CD Changer

mode (analog)

Tape mode

(digital)

Traffic info

play mode

AM/FM MPX

(analog)

DSP1

Main source

and RDS

Alternative

Rear Source

and RDS

Alternative

Rear Source

and RDS

Alternative

Rear Source

and RDS

Alternative

Rear Source

and RDS

CD changer

(analog)

DSP1

Alternative

Rear Source

Alternative

Rear Source

Main source

Alternative

Rear Source

Alternative

Rear Source

Phone/Navi

(analog)

DSP0

Summed to

Main source

Summed to

Main source

Summed to

Main source

Summed to

Main source

Summed to

Main source

CD/CD ROM

audio/MP3

(digital SPDIF)

DSP1

Alternative

Rear Source

through SRC

Main source

through SRC

Alternative

Rear Source

through SRC

Alternative

Rear Source

through SRC

Alternative

Rear Source

through SRC

Tape via ADC

(digital SAI)

Dolby B on

DSP1

Alternative

Rear Source

Alternative

Rear Source

Alternative

Rear Source

Main source

Alternative

Rear Source

DSP co-processor

MDSP: master

CO-dsp: slave

Traffic info

storage

DSP0

Background

recording

Background

recording

Background

recording

Background

recording

Main source

& Background

recording

MOST bus

MDSP: slave

Co-dsp: slave

MOST: master

1.

The total number of SAI channels is six. They must be split between MOST, Co-DSP and the external ADC for tape. In case

of MOST, the DSP clock must be synchronized to the MOST bus.