User Guide

RAE-6/RA-4
Nokia Customer Care 6 - Baseband Description and Troubleshooting
22 COMPANY CONFIDENTIAL Issue 1 12/04
Copyright © 2004 Nokia. All Rights Reserved.
Table 5: BSI Resistor Values
■ Charging
RAE-6/RA-4 supports all DCT4 chargers. 3-wire chargers are supported, but 3-wire charging
is not. In practice, this means that the 3-wire chargers are internally connected (charger control
wire connected to GND) as 2-wire chargers. 1Hz PWM signal is used to control UEMEK's
charge switch.
■ Backup battery and RTC
Rechargeable backup battery is used for keeping real time clock running in case the main bat-
tery is either removed or the power level is below the cutoff limit.
Real Time Clock (RTC), crystal oscillator and backup battery circuitry are inside UEMEK. Two
regulators are used to provide needed voltages for external backup supply and backup battery
charging: VRTC for internal clock circuitry and VBU for backup battery charging. The backup
battery has voltage range VBACK = 2.0V
min
– 3.2V
typ
– 3.3V
max
(charged to 3.2V and dis-
charged down to 2.0V).
■ Display and keypad illumination
One DC-DC converter generates the voltage for displays and keypad illumination. The convert-
er is able to supply cover display and keypad OR PDA display, but both cannot be active at the
same time. UEMEK controls the DC-DC converter and selection of cover/PDA display under
APE control. The brightness of both cover and PDA display can be adjusted with UEMEK PWM
output. For further details, see RAE-6/RA-4 flex section.
■ Power up and system states
System starts automatically after the battery is inserted. The power button is connected to
UEMEK PWRONX pin on the CMT side. This power button is only used for selecting operating
mode and switching the RF part of the device ON and OFF when needed. APE is started when
UEMEK releases a PURX-signal, which controls OMAP1510 processor reset input.
Power off happens in the lowest SW cutoff limit when UEMEK watchdog is not updated any-
more by SW and after that PURX goes to reset and system power supplies are switched OFF.
However also in this power OFF mode (BACK_UP mode in UEMEK) part of UEMEK is pow-
ered ON but for user the device is dead. Only way to wake up from this mode is to plug in the
charger or replace empty battery with the charged one.
Parameter Min Typ Max Unit Notes
Battery size indicator resistor
BSI
82 kOhm Battery size indicator for 970 mAh
battery (BP-6M), Tolerance +/- 1%
NTC thermistor BTEMP
(inside phone)
47 kOhm Battery temperature indicator
(NTC pulldown) 47kOhm +/- 5% @
25C
4000 Ohm Beta value (B).
Tolerance ”5%, 25C / 85C