Fm Radio Interface - Nokia 6720 Service Manual

RM-424; RM-564
System Module
Figure 66 Bluetooth interface
The BTHFM module is powered by VBAT and the regulated voltage VIO. For audio applications the Bluetooth
has a PCM data bus. In addition an UART (universal asynchronous receiver/transmitter) is used for data
communication and controls.

FM radio interface

The FM radio system is controlled by RAPU via the I2C bus. EM ASIC delivers the needed voltages and the clock
reference (32.768kHz SleepClk). EM ASIC also processes the analog audio.
The FM receiver fully supports reception over US/European (87.5MHz to 108MHz) FM band. The FM receiver
comprises an RF receiver with fully integrated VCO, a stereo FM demodulator and a RDS demodulator.
A headset accessory is used as an external antenna. The headset is connected to the AV connector.
FM radio is physically integrated with Bluetooth in the BTHFM module ASIC, but from a functional point of
view FM radio and Bluetooth have nothing in common.
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