Reset And Power Control - Nokia 9000i Service Manual

After Sales
Technical Documentation
The DSP has its own crystal oscillator which can be turned off and on by
the ASIC. The DSP uses differential sinusoidal clock. The frequency is
60.2 MHz.
The MCU generates 8 kHz clock to the codec for the control data transfer.
In the idle mode all the clocks can be stopped except 26 MHz main clock
coming from the VCXO.

Reset and power control

reset in
DSP
PSL+
VL1
XRES
XPWRON
approx 2Hz
XPwrOff
There are three different ways to switch power on:
Pulling the XPWRON line down e.g by pressing the power key. The PSL+
detects that and switches the power on.
Charger detection on PSL+ detects that charger is connected and
switches power on
PSL+ will switch power on when the battery is connected. After that the
MCU will detect if power key is pressed or charger connected. If not the
power will be switched off
Original, 08/96
RFI
Reset in
Reset Out
Reset Out
ASIC
Vcc
Reset in
reset in
MCU
Figure 4. Reset and Power Control
resetreg
XPWRON
RAE/RAK–1N
Baseband
SIMReset
Page 2–19