User Guide

Nokia Customer Care System Module

RH-37

Issue 1 07/04 Nokia Corporation Page 19

Sleep Mode

Sleep mode is entered when both MCU and DSP are in stand–by mode. Both processors

control the sleep mode. When SLEEPX signal (low) is detected UEMEK enters SLEEP

mode. VCORE, VIO and VFLASH1 regulators are put into low quiescent current mode. All

the RF regulators are off in SLEEP. When SLEEPX=1 detected UEMEK enters ACTIVE mode

and all functions are activated.

The sleep mode is exited either by the expiration of a sleep clock counter in the UEMEK

or by some external interrupt, generated by a charger connection, key press, headset

connection etc.

In the sleep mode, VCTCXO is shut down and 32 kHz sleep clock oscillator is used as ref-

erence clock for the Baseband.

Charging

In RH-37, the battery type/size is indicated by a BSI-resistor. The resistor value corre-

sponds to a specific battery capacity. Also BTEMP, NTC resistor, is located on an engine

board.

The battery voltage, temperature, size and current are measured by the UEMEK con-

trolled by the charging software running in the UPP.

The charging control circuitry (CHACON) inside the UEMEK controls the charging current

delivered from the charger to the battery. The battery voltage rise is limited by turning

the UEMEK switch off when the battery voltage has reached 4.2 V. Charging current is

monitored by measuring the voltage drop across a 220 mΩ resistor.

Power distribution

Under normal conditions, the battery powers the baseband module. Individual regulators

located within the UEMEK regulate the battery voltage VBAT. These regulators supply the

different parts of the phone. 7 regulators are dedicated to the RF module and 7 to the

baseband module.

The VSIM regulator is able to deliver both 1,8V and 3,0 V DC and thus supporting two

different SIM technologies.

The regulator VCORE is likewise adjustable by the MCU. VCORE supplies the core logic of

the UPP.

The system connector provides a voltage to supply accessories.

The white LEDs need a higher voltage supply than the battery can supply and are fed by a

separate external voltage regulator.

VBAT is directly distributed to the RF power amplifier, FCI and external baseband regula-

tors.