User Guide

PAMS
Technical Documentation
NSE–8/9
System Module
Page 2– 43
Issue 1 07/99
Power up reset, PURX, is the main reset of the system. It is controlled by
the CCONT digital part and is released in the power up. PURX is related
to the CCONT watchdog which in turn is the main watchdog of the
system. CCONT watchdog is controlled by the MCU SW which has to
update it at regular intervals. If the CCONT watchdog expires then PURX
goes activate and the power of the phone is turned off. The watchdog
maximum value is 64 s and the default value is 32 s.
System reset is a general purpose reset and is used to reset the phone at
any time when the phone is operating, i.e. PURX is not active. System
reset goes asynchronously active if MCU writes the software reset or if the
software watchdog expires. System reset follows also the power up reset,
i.e. system reset is active when PURX is active.
One of the DSP controlled general purpose output lines, DSPGenOut_5 is
used for COBBARESET. The reason for having a separate reset for
COBBA is to allow the DSP SW to reset COBBA without resetting other
parts of the system. Because COBBA reset is a lower level reset than
power up reset, system reset and DSP reset, it is activated also when
these resets are activated. COBBA reset is released by DSP software.
The MCU controlled general purpose I/O line, MCUGenIO_2, is used as
the LCD driver reset. MCU SW can activate and release the reset. LCD
driver is not connected to the system reset because having a separate
reset for it allows resetting the system without the user knowing it.
MAD2PR1 generates reset to SIM card, SIMIF_2. The reset goes to the
SIM card via the CCONT SIM interface block.
Power Supply
The DC/DC converter is the only unit which draws current from the 2 cell
NiMH battery pack. The battery voltage, Vb, is up converted through the
DC/DC converter to an output voltage level, Vdc_out, which is dependent
on the phone state (operating mode) and in call mode depending upon
which band and on what power level the phone is transmitting at.
The DC/DC converter feeds power directly to four parts of the system: the
CCONT, the power amplifier, the UI (buzzer, Vibra, display– and
keyboard– lights) and for a separate regulator in the RF.
The Baseband contains components that control power distribution to the
whole phone, except for the PA control in RF.
The battery consists of two NiMH cells and a polyswitch, all assembled
into the battery pack. An external charger can be used for recharging the
battery and supplying power to the phone. The charger can be either a
two wire type of charger, or a 3–wire charger, so called performance
charger.
The power management circuit PSCC provides protection against over
voltages, charger failures and pirate chargers etc. that would otherwise
cause damage to the phone.