Sleep Mode; Charging; Power Up And Reset - Nokia NSB-9 Service Manual

CCS Technical Documentation
One of the sub-state of the active mode is FM radio on state. In that case UEM audio
blocks, stereo amplifier and FM radio are powered on. FM radio circuitry is controlled by
the MCU and 32kHz reference clock is supplied by the UPP. VFLASH2 regulator is operat-
ing.
In active mode the RF regulators are controlled by SW writing into UEM's registers
wanted settings: VR1A can be enabled or disabled. VR2 can be enabled or disabled and
its output voltage can be programmed to be 2.78V or 3.3V. VR4 - VR7 can be enabled or
disabled or forced into low quiescent current mode. VR3 is always enabled in active
mode.

Sleep mode

Sleep mode is entered when both MCU and DSP are in stand-by mode. Sleep is controlled
by both processors. When SLEEPX low signal is detected UEM enters SLEEP mode. VCORE,
VIO and VFLASH1 regulators are put into low quiescent current mode. All RF regulators
are disabled in SLEEP. When SLEEPX=1 is detected UEM enters ACTIVE mode and all
functions are activated.
The sleep mode is exited either by the expiration of a sleep clock counter in the UEM or
by some external interrupt, generated by a charger connection, key press, headset con-
nection etc.
In sleep mode VCTCXO is shut down and 32 kHz sleep clock oscillator is used as reference
clock for the baseband.

Charging

Charging can be performed in any operating mode. The battery type/size is indicated by a
resistor inside the battery pack. The resistor value corresponds to a specific battery
capacity. This capacity value is related to the battery technology as different capacity
values are achieved by using different battery technology.
The battery voltage, temperature, size and current are measured by the UEM controlled
by the charging software running in the UPP. Only Li-ion batteries are charged by NSB-9.
The charging control circuitry (CHACON) inside the UEM controls the charging current
delivered from the charger to the battery. The battery voltage rise is limited by turning
the UEM switch off when the battery voltage has reached 4.2 V. Charging current is
monitored by measuring the voltage drop across a 220 mΩ precision resistor.

Power Up and Reset

Power up and reset is controlled by the UEM ASIC. NSB-9 baseband can be powered up
in following ways:
1 Press power button which means grounding the PWRONX pin of the UEM
2 Connect the charger to the charger input
3 Supply battery voltage to the battery pin
Issue 1 04/03
System Module and User Interface
Nokia Corporation
NSB-9
Page 25