Nokia NPL-4 Series Manual page 14

NPL-4/5/RM-104
System Module and User Interface
UEMEK is a dual voltage circuit, the digital parts are running from the baseband supply
1.8V and the analog parts are running from the analog supply 2.78V.
VBAT is directly used for Vibra, LED-driver, Audio amplifier and FCI (Functional Cover
Interface).
The baseband architecture supports a power saving function called "sleep mode". This
sleep mode shuts off the VCTCXO, which is used as system clock source for both RF and
baseband. During the sleep mode the system runs from a 32 kHz crystal. The phone is
waken up by a timer running from this 32 kHz clock supply. The sleep time is determined
by network parameters. Sleep mode is entered when both the MCU and the DSP are in
standby mode and the normal VCTCXO clock is switched off.
The baseband supports both internal and external microphone inputs and speaker out-
puts. UEMEK also includes third microphone input. This input is used for FM-radio. Input
and output signal source selection and gain control is done by the UEMEK according to
control messages from the UPP. Keypad tones, DTMF, and other audio tones are gener-
ated and encoded by the UPP and transmitted to the UEMEK for decoding. An external
vibra alert control signals are generated by the UEMEK with separate PWM outputs.
The NPL-4/5 uses D-class amplifier to amplifying IHF speaker audios. It gives more sound
pressure from speaker and efficiency is in good level to improve thermal performance
compared to AB-class.
VGA Camera is connected to baseband (UPP) through HW accelerator IC. The camera
data bus is common with display bus. The HWA is taking care of camera control and it is
compressing the pictures.
NPL-4/5 has 2-axes electrical compass. It is implemented with magnetoresistive sensor
and MagIC ASIC.
NPL-4/5 has two serial control interfaces: FBUS and MBUS. FBUS and MBUS can be
accessed through production test pattern and FBUS can be also accessed thought Toma-
hawk System Connector.
The FCI interface is located to front bottom side area of the phone. This means that only
B-cover can be an active cover.
EMC shielding is implemented using a metal body profile, RF cans and PWB grounding.
Some components are outside of shielding. Heat generated by the circuitry is conducted
out via the PWB ground planes and by using buried vias between PWB layers.
Copyright © 2005 Nokia Corporation. All rights reserved.
Page 14
Nokia Customer Care
Issue 2 05/05