Power down procedure
Controlled powering off is done with the aid of SW when the user requests it or when the battery voltage is
falling too low. Uncontrolled powering off happens for example when battery is suddenly removed.
Clocking scheme
The main system clock is a small signal sine wave created in the RF-section of the engine with Voltage
Controlled, Temperature Compensated, crystal oscillator (VCTCXO). The delivered frequency is 38.4MHz . RAP
has its own sleep mode in which use low accuracy, low frequency sleep clock instead of RF clock. In deep
sleep, ASIC is sleep mode and therefore VCTCXO can be switched off (VCTCXO is a significant power consumer).
In deep sleep also the core voltage is decreased.
Bluetooth
The device uses BTH Perf2.3 solution. The Bluetooth is V 2.0 + EDR. The Bluetooth module is implemented by
using CSR’s BC4-ROM. BlueCore-4 ROM is a single chip radio and baseband IC for Bluetooth 2.4 GHz systems.
In BB5.0 ,BT interface has been designed so that it allows attaching BT modules from different vendors. The
interface consists of UART interface and PCM interface for audio.
RM-88
Nokia Customer Care
System Module
Page 8 –10
COMPANY CONFIDENTIAL
Issue 1
Copyright © 2006 Nokia. All rights reserved.
