Nokia NSB-6 Series Technical Documentation Manual

Also see for NSB-6 Series: Disassembly & troubleshooting instructions

Nokia NSB-6 Series Technical Documentation Manual Manual pdf 23 page image

NSB–6System ModulePAMS Technical DocumentationPage 23Issue 1 06/2000 Nokia Mobile Phones Ltd.4. Setting the real time clock to power off the phone by a timer.The RTC generates an interrupt signal, when the alarm is goneoff. The RTC interrupt signal is connected to the PWRONX lineto 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 beenpressed long enough or the battery voltage is dropped below the limit theMCU initiates a power down procedure and disconnects the SIM power.Then the MCU outputs a system reset signal and resets the DSP. If thereis no charger connected the MCU writes a short delay to CCONT watch-dog and resets itself. After the set delay the CCONT watchdog expires,which activates the PURX and all regulators are switched off and thephone is powered down by the CCONT.If a charger is connected when the power key is pressed the phone en-ters into the acting dead mode.Modes of OperationActing DeadIf the phone is off when the charger is connected, the phone is poweredon but enters a state called ”acting dead”. To the user the phone acts as ifit was switched off. A battery charging alert is given and/or a batterycharging indication on the display is shown to acknowledge the user thatthe battery is being charged.Active ModeIn the active mode the phone is in normal operation, scanning for chan-nels, listening to a base station, transmitting and processing information.All the CCONT regulators are operating. There are several substates inthe active mode depending on if the phone is in burst reception, bursttransmission, if DSP is working etc.Sleep ModeIn the sleep mode all the regulators except the baseband VBB and theSIM card VSIM regulators are off. Sleep mode is activated by the MADafter MCU and DSP clocks have been switched off. The voltage regula-tors 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 oscillator inCCONT is running. The flash memory power down input is connected tothe ExtSysResetX signal, and the flash is deep powered down during thesleep mode.The sleep mode is exited either by the expiration of a sleep clock counterin the MAD or by some external interrupt, generated by a charger con-nection, key press, headset connection etc. The MAD starts the wake upsequence and sets the VCXOPwr and ExtSysResetX control high. AfterVCXO settling time other regulators and clocks are enabled for activemode.