PAMS Technical Documentation
System Module
NSB-7
Issue 1 06/00
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Nokia Mobile Phones Ltd.
Page 25
the phone is powered down.
4
Setting the real time clock to power off the phone by a timer. The RTC generates
an interrupt signal, when the alarm is gone off. The RTC interrupt signal is connected to
the PWRONX line to give a power off signal to the CCONT just like the power key.
The power down is controlled by the MAD. When the power key has been pressed long
enough or the battery voltage is dropped below the limit the MCU initiates a power
down procedure and disconnects the SIM power. Then the MCU outputs a system reset
signal and resets the DSP. If there is no charger connected the MCU writes a short delay
to CCONT watchdog and resets itself. After the set delay the CCONT watchdog expires,
which activates the PURX and all regulators are switched off and the phone is powered
down by the CCONT.
If a charger is connected when the power key is pressed the phone enters into the acting
dead mode.
Modes of Operation
Acting Dead
If the phone is off when the charger is connected, the phone is powered on but enters a
state called ”acting dead”. To the user the phone acts as if it was switched off. A battery
charging alert is given and/or a battery charging indication on the display is shown to
acknowledge the user that the battery is being charged.
Active Mode
In the active mode the phone is in normal operation, scanning for channels, listening to
a base station, transmitting and processing information. All the CCONT regulators are
operating. There are several sub-states in the active mode depending on if the phone is
in burst reception, burst transmission, if DSP is working etc.
Sleep Mode
In the sleep mode all the regulators except the baseband VBB and the SIM card VSIM
regulators are off. Sleep mode is activated by the MAD after MCU and DSP clocks have
been switched off. The voltage regulators for the RF section are switched off and the
VCXO power control, VCXOPwr is set low. In this state only the 32 kHz sleep clock oscil-
lator in CCONT is running. The flash memory power down input is connected to the Ext-
SysResetX signal, and the flash is deep powered down during the sleep mode.
The sleep mode is exited either by the expiration of a sleep clock counter in the MAD or
by some external interrupt, generated by a charger connection, key press, headset con-
nection etc. The MAD starts the wake up sequence and sets the VCXOPwr and ExtSysRe-
setX control high. After VCXO settling time other regulators and clocks are enabled for
active mode.
If the battery pack is disconnect during the sleep mode, the CCONT pulls the SIM inter-
face lines low as there is no time to wake up the MCU.
