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Philips Semiconductors
User Manual of High-End RDS/EON
Car Radio System CCR612 (V0.3)
Application Note
96029
6.3.3 Cassette functions
The cassette interface is based on a mechanical tape deck. When a cassette is playing, the display will
show the text "PLAY >" or "PLAY <" indicating the play direction. During fast winding, no direction
information is available. The display will show "CAS WIND". When fast winding for more than 4 seconds,
the set will temporarily switch to radio mode.
While in cassette mode, the keys P-4, P-5/PRE-UP and P-6/PRE-DOWN control the functions AMS
(Automatic Music Search), MTL (Metal/Chromium) and Dolby respectively. The keys toggle the
corresponding output pins, the function itself is executed by the cassette deck circuitry. When a function
is not available in the cassette deck, the corresponding pin must be connected to ground.
The state of the AMS, ME/CR and Dolby functions is displayed by icons. If a TEA632x is installed the
cassette solenoid and AMS pause function are available. The solenoid function takes care of playing in
the correct direction after switching to cassette mode and together with the AMS pause function, it takes
care of controlling the AMS function. Search (in both directions) for the next music piece by detecting a
blank area on the tape. If no TEA632x is installed (potentiometer sound control) the AMS function and the
solenoid function are not available. If the cassette drive does not have the AMS function the CAMS pin
must be connected to ground.
6.3.4 External audio source
An external audio input is available to connect e.g. a CD player. The external input jack has a switch to
sense whether aconnector is inserted. Whilethe radio is in externalmode, the text "EXTERNAL"is shown
on the display. When no external audio selection is available the EXSTAT pin must be connected to
Ground.
6.4 Audio control
Most of the audio control facilities are available only if a digital sound and fader control chip (Sofac) is
installed. If no digital sound control chip is used, the following signals should be used in combination with
potentiometer control:
- pin AUMUTE Mute status;
- pin LOUDN Loudness status;
- pin TA Traffic announcement or PTY alarm message in progress;
- pin SEL0 / SEL1 Source selection.
The volume at power on is limited to -10 dB when digital sound control is available.
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