Nokia 8208 Service Manual page 130

Other Circuits
Sound Activation Circuit
As a device to generate sound, speaker activates the signal from audio front-end stage of MSM by
speaker amplifier (U502).
Touch sensor Activation Circuit
There is a touch sensor in up-board. In the mode of sensor, it is controlled through I2C interface as
well as touch sensor
MMC Circuit
In the MMC mode, LDO7 in PMIC is turning on and controlled through I2C interface.
Camera Circuit.
In the camera mode, Use Dual LDO in main PCB is turning on and controlled through I2C interface.
Vibration Circuit
In the mode of vibration,U629 receives the VIB_EN signal and activates motor for vibration.
Ear Jack Circuit
This block is arranged for the external ear phone through Ear Jack. Once ear Jack is connected,
internal MIC and Speaker are switched to earphone and communication through earphone is
possible.
Charger Detection
Connecting a charger creates a voltage on the VCHG ("VCHG" pin in 8208 schematic) input of the PMIC. Charging
starts when the PMIC detects the VCHG input voltage level above 4.5V (Min. working voltage of VCHG pin).The
VCHG signal of PMIC is generated to indicate the presence of the charger for the software. The power
management (PM) software controls the charger identification/ acceptance. The charger recognition is initiated
when the EM software receives a "charger connected" interrupt.
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System Module and User Interface
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