FM radio
FM radio circuitry is implemented using the highly integrated FM radio ASIC, TEA5767. The MCU SW controls the
FM radio circuitry through a proprietary 3-wire bus.
The stereo output is fed to the UEMEK via one of the microphone inputs, MIC3.
The antenna of the FM Radio is created with the headset. The wires of the headset are used as antenna.
The data bus on the radio will be disabled when not used, in order to save current (BUSENABLE).
The VAUX1 regulator of the UEMEK will power the FM radio at nominal 3 V.
The reference clock for the FM radio is the SleepClk signal picked up through a resistive divider.
Flashing
SW download in service is implemented by custom tools and SW; kindly refer to
sections of the manual.
ACI/BSI implementation
The ACI bus is implemented a little different from most Nokia mobile devices. The functionality is the same but
some functions have been moved a little around. The battery detect function is handled by connecting the BSI
of the battery to the SimCardDet input of UEMEK. The Battery Size Indication functionality is handled by
connecting the BSI of the battery to the Alco/LS AD input of the UEMEK. The ACI bus of the ACI accessories is fed
via a level shifter to the BSI/BDI pin of the UEMEK. Via this pin the ACI accessory communicates over the C-bus
with the MCU of the UPP_WD2. The BSI_PULS delivered at one of the Flash/Test pads by the Flash equipment
when the mobile is to be reflashed is connected to the BSI pin of UEMEK. The ACI accessory is connected to
HeadInt to interrupt the MCU when accessory is attached/detached.
Battery voltages
Lithium-Ion battery BL-5B (1 cell):
• Nominal voltage is 3.7 V
• Lower extreme voltage is 2.8 V (cut off voltage)
• Higher extreme voltage is 4.2 V (charging high limit voltage)
RF description
The RF module has 2 SAW filters, a capacitor on the 1KMA system module, and an antenna module.
The main ASIC of RF is Helgo 86G, and power amplifier is RFMD RF9250, a so called microPA. EDGE downlink is
supported.
For more information, see the RF troubleshooting chapter.
RM-51
System module and user interface
Nokia Customer Care
9238460 (Issue 1)
Company Confidential
Page 9–15
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