Power Off; Watchdog - Nokia NSE-6 SERIES Service Manual

PAMS
Technical Documentation
The battery voltage, temperature, size and current are measured by the
CCONT controlled by the charging software running in the MAD.
The power management circuitry controls the charging current delivered
from the charger to the battery. Charging is controlled with a PWM input sig-
nal, generated by the CCONT. The PWM pulse width is controlled by the
MAD and sent to the CCONT through a serial data bus. The battery voltage
rise is limited by turning the CHAPS switch off when the battery voltage has
reached 4.2V (LiIon) or 5.2V (NiMH, 5V in call mode). Charging current is
monitored by measuring the voltage drop across a 220mohm resistor.

Power Off

The baseband is powered down by:
1.
2.
3.
4.
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 en-
ters into the acting dead mode.

Watchdog

The Watchdog block inside CCONT contains a watchdog counter and
some additional logic which are used for controlling the power on and
power off procedures of CCONT. Watchdog output is disabled when
WDDisX pin is tied low. The WD-counter runs during that time, though.
Watchdog counter is reset internally to 32s at power up. Normally it is re-
set by MAD writing a control word to the WDReg. Watchdog counter can
be disabled b grounding J111.
Original 08/98
Pressing the power key, that is monitored by the MAD via key-
board line (row 4), which starts the power down procedure.
If the battery voltage is dropped below the operation limit, ei-
ther by not charging it or by removing the battery.
Letting the CCONT watchdog expire, which switches off all
CCONT regulators and the phone is powered down.
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.
NSE–6
System Module
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