User Guide

RH-26
2 - System Module CCS Technical Documentation
Page 10 ©Nokia Corporation Issue 1 02/04
A real time clock function is integrated into the UEMK, which utilises 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 cell capacitor. The backup time with the
cell capacitor is 15 minutes minimum.
The interface between the baseband and the RF section is mainly handled by a UEMK
ASIC. UEMK provides A/D and D/A conversion of the in-phase and quadrature receive and
transmit signal paths and also A/D and D/A conversions of received and transmitted
audio signals to and from the user interface. The UEMK supplies the analog TXC and AFC
signals to the RF section according to the UPP DSP digital control. Data transmission
between the UEMK 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. UEMK is a dual voltage circuit, the
digital parts are running from the baseband supply 1.8V and the analogue parts are run-
ning from the analogue supply 2.78V also VBAT is directly used by some specific blocks.
The baseband supports both internal and external microphone inputs and speaker out-
puts. Input and output signal source selection and gain control is done by the UEMK
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 UEMK for decoding. An
external vibra alert control signal is generated by the UEMK with separate PWM output.
RH-26 has two external serial control interfaces: FBUS and MBUS. FBUS can be accessed
through service test pattern and Pop-Port
TM
System Connector. FBUS interface and
MBUS can be accessed through the service test pattern.
EMC shielding is implemented using soldered metal cans. Heat generated by the circuitry
is conducted out via ground planes located in the PWB.
The RH-26 PWB is implemented into an 8-layer selective OSP coated PWB using buried
via technology.
Main technical specifications
DC characteristics
Regulators and supply voltage ranges
Table 1: Baseband regulators
Signal Min Nom Max Note
VANA 2.70V 2.78V 2.86V I
max
= 80mA
VFLASH1 2.70V 2.78V 2.86V I
max
= 70mA
I
sleep
= 1.5mA
VFLASH2 2.70V 2.78V 2.86V I
max
= 40mA