User Guide

CCS Technical Documentation System Module and User Interface
Company confidential RH-23
Issue 1 02/2004 Nokia Corporation. Page 5
Baseband Module
Technical summary
Main functionality of the baseband is implemented into two ASICs: UPP (Universal Phone
Processor) and UEM (Universal Energy Management).
Baseband is running from power rails 2.8V analog voltage and 1.8V I/O voltage. UPP core
voltages can be lowered down to 1.0V, 1.3V and 1.57V. RH-23 core voltage is 1.57V. UEM
includes 6 linear LDO (Low Drop-Out) regulator for baseband and 7 regulators for RF. It
also includes 4 current sources for biasing purposes and internal usage. UEM also
includes SIM interface which supports both 1.8V and 3V SIM cards.
A real time clock function is integrated into the UEM. RTC utilizes the same 32kHz clock
supply as the sleep clock. A backup power supply is provided for the RTC-battery, which
keeps the real time clock running when the main battery is removed. The backup power
supply is a rechargeable surface mounted Li-Ion battery. The backup time with the bat-
tery is 30 minutes minimum.
The UEM ASIC handles the analog interface between the baseband and the RF section.
UEM provides A/D and D/A conversion of the in-phase and quadrature receive and trans-
mit signal paths and also A/D and D/A conversions of received and transmitted audio sig-
nals to and from the user interface. The UEM supplies the analog TXC and AFC signals to
RF section according to the UPP DSP digital control. Data transmission between the UEM
and the UPP is implemented using two serial busses, DBUS for DSP and CBUS for MCU.
There are also separate signals for PDM coded audio. Digital speech processing is handled
by the DSP inside UPP ASIC. UEM 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.
The baseband supports both internal and external microphone inputs and speaker out-
puts. Input and output signal source selection and gain control is performed by the UEM
according to control messages from the UPP. Keypad tones, DTMF, and other audio tones
are generated and encoded by the UPP and transmitted to the UEM for decoding. An
external vibra alert control signals are generated by the UEM with separate PWM out-
puts. RH-23 has a serial control interface: FBUS. FBUS can be accessed through a test
pad and the Pop-Port as described later. EMC shielding is implemented using metal cans.