User Guide

RH-25
System Module CCS Technical Documentation
Page 8 ©Nokia Corporation Confidential Issue 1 10/2003
processors are located in the UPP.
The interface between baseband and RF is implemented in the UEM and UPP ASIC. The
UEM provides A/D and D/A conversion of the in-phase and quadrature receive and trans-
mit signal paths. It also provides A/D and D/A conversions of received and transmitted
audio signals to and from the user interface. The UEM supplies the analog signals to RF
section according to the UPP DSP digital control. The RF ASIC, TACO, is controlled via the
UPP RFBUS serial interface. There are also separate signals for PDM coded audio. Digital
speech processing is handled by the DSP inside the UPP ASIC. The UEM is a dual voltage
circuit with the digital parts running from the baseband supply (1.8V) and the analog
parts running from the analog supply of 2.78V. The input battery voltage (VBAT) is also
used directly by some UEM blocks.
The baseband supports both internal and external microphone inputs as well as speaker
outputs. Input and output signal source selection and gain control is done 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. RH-25
has two external serial control interfaces: FBUS and MBUS provided by UEM. These bus-
ses can be accessed only through production test patterns.
RH-25 uses UPP8Mv2.4 and UEMK, with provision to use UEMC and future releases of
UPP as it becomes necessary. UEMC requires some software changes.
Battery
BLD-3 Li-ion (inbox battery) is used as main power source for RH-25. No other battery
packs are planned to be used. BLD-3 has the capacity of 780 mAh.
Table 1: BLD-3 characteristics
Description Value
Nominal discharge cut-off voltage 3.1V
Nominal battery voltage 3.7V
Nominal charging voltage 4.2V
Maximum charger output current 850mA
Minimum charger output current 200mA
Cell pack impedance -20 ... 0
o
C
180mΩ max
Cell pack impedance 0 ... +20
o
C
150mΩ max
Cell pack impedance +20 ...+60
o
C
130mΩ max
Cell pack impedance +60 ...+80
o
C
250mΩ max