Siemens A55 Repair Documentation page 32

Functions Pin
Requirements
Ringer function RINGIN
Key click function
Audio Multiplex AUDIOA1
Matrix AUDIOA2
AUDIOB1
AUDIOB2
AUDIOC1
AUDIOC2
I2S Interface CLO,
WAO,
DAO
V 1.10
A52/A55/C55 IFX
Sequence
In ringer mode the ringing signal is transferred
via the amplifier to the speaker to eliminate the
additional buzzer. The speaker is controlled
with a rectangular signal
signal is digital signal with variable frequency.
Amplitude is adjusted by TWI register.
For start-up a smaller time constant must be
used to allow a fast switch on behavior. Ringing
function can be started at any time. If the audio
is off, the start-up is done with RINGER time
constant. If audio is starting with AUDIO start-
up, the time constant is switched to RINGER
mode, too. If the audio amplifier is already up
and running, the
to the amplifier and audio signal is muted due
to open multiplexer.
Pushing a key of the phone can be combined
with a key click. This function is also realized
with the audio amplifier in pulsed mode. The
ASIC creates a digital PWM signal. Frequency
of the PWM signal is 3.5 kHz.
The start-up is similar to the ringer function. If
the audio is off, the start-up is done with
KEYCLICK time constant. If audio is starting
with AUDIO start-up, the time constant is
switched to KEYCLICK mode, too. If the audio
amplifier is already up and running, the
KEYCLICK is connected to the amplifier and
audio signal is muted due to open multiplexer.
Each of the three input sources should be
switched
Furthermore a conversion can be done.
Following sources:
Mono differential
-
- Mono
parallel)
- Stereo
The DAC can be switched off for using the
analog external inputs. This principle will allow
to do each combination and have different
modes for stereo and mono in parallel.
The I2S Interface is a three-wire connection
that handles
channels. The three lines are the clock (CLO),
the serial data line (DAO) and the word select
line (WAO). The master I2S also generates the
appropriate clock frequency for CLO set to 32
times the sampling rate (FS)
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RINGIN (PinG9). Input
RINGIN (PinG9) is connected
to Mono and Stereo
Single Ended (both
two time multiplexed
outputs.
channels
data
ICM MP CCQ GRM
08/03