Nokia 8850 Manual Do Serviço
NSM–2
System Module
System Module
PAMS Technical Documentation
Page 8
Issue 1 12/1999
Nokia Mobile Phones Ltd.
System Module
Baseband Module
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 sys-
tem runs from a 32 kHz crystal. The phone is waken up by a timer run-
ning from this 32 kHz clock supply. The sleeping time is determined by
some network parameters. The sleep mode is entered when both the
MCU and the DSP are in standby mode and the normal VCTCXO clock
has been switched off.
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 sys-
tem runs from a 32 kHz crystal. The phone is waken up by a timer run-
ning from this 32 kHz clock supply. The sleeping time is determined by
some network parameters. The sleep mode is entered when both the
MCU and the DSP are in standby mode and the normal VCTCXO clock
has been switched off.
The battery charging is controlled by a PWM signal from the CCONT. The
PWM duty cycle is determined by a charging software and is fed to the
CHAPS charging switch.
PWM duty cycle is determined by a charging software and is fed to the
CHAPS charging switch.
Standard chargers (two wires) provide coarse supply power, which is
switched by the CHAPS for suitable charging voltage and current. Ad-
vanced chargers (three wires) are equipped with a control input. Three
wire chargers are treated like two wire ones.
switched by the CHAPS for suitable charging voltage and current. Ad-
vanced chargers (three wires) are equipped with a control input. Three
wire chargers are treated like two wire ones.
Block Diagram
CCONT
UI
SIM
MAD
CHAPS
COBBA
BATTERY
PA SUPPLY
RF SUPPLIES
BB SUPPLY
TX/RX SIGNALS
BASEBAND
VBAT
+
MEMORIES
COBBA SUPPLY
EXT. AUDIO
IR
32kHz
CLK
CLK
13MHz
CLK
CLK
SLEEP CLOCK
SYSTEM CLOCK
HS–connector
Charger
connector
connector