Nokia RH-9 Series Ccs Technical Documentation page 26

RH-9
System Module & UI
the section Power Up and Reset. Pressing the power key causes the PWRONX pin on the
UEM to be grounded. The UEM PWRONX signal is not part of the keypad matrix. The
power key is only connected to the UEM. This means that when pressing the power key
an interrupt is generated to the UPP that starts the MCU. The MCU then reads the UEM
interrupt register and notice that it is a PWRONX interrupt. The MCU now reads the sta-
tus of the PWRONX signal using the UEM control bus, CBUS. If the PWRONX signal stay
low for a certain time the MCU accepts this as a valid power on state and continues with
the SW initialization of the baseband. If the power on key does not indicate a valid
power on situation the MCU powers off the baseband.
Power up when charger is connected
In order to be able to detect and start charging in a case where the main battery is fully
discharged (empty) and hence UEM has no supply (NO_SUPPLY mode of UEM) charging
is controlled by START-UP CHARGING circuitry.
Whenever VBAT level is detected to be below master reset threshold (V
controlled by START_UP charge circuitry. Connecting a charger forces VCHAR input to
rise above charger detection threshold, VCH
started. UEM generates 100mA constant output current from the connected charger's
output voltage. As battery charges its voltage rises, and when VBAT voltage level higher
than master reset threshold limit (V
Monitoring the VBAT voltage level is done by charge control block (CHACON). MSTRX='1'
output reset signal (internal to UEM) is given to UEM's RESET block when VBAT>V
and UEM enters into the reset sequence described in section Power Up and Reset.
If VBAT is detected to fall below V
It will restart if new rising edge on VCHAR input is detected (VCHAR rising above VCH-
).
DET+
Power up when battery is connected
Baseband can be powered up by connecting battery with sufficient voltage. Battery volt-
age has to be over UEM internal comparator threshold level, V
specified in Table 2. When battery proper voltage is detected UEM enters to reset
sequence as described in section Power Up and Reset. This power up sequence is meant
for test purposes, in normal use (Btemp resistor > 1kΩ) the phone will power off again
immediately, without noticing the user.
RTC alarm power up
If phone is in POWER_OFF mode when RTC alarm occurs the wake up procedure is as
described in section Power Up and Reset. After baseband is powered on an interrupt is
given to MCU. When RTC alarm occurs during ACTIVE mode the interrupt for MCU is
generated.
Page 26
DET+
) is detected START_UP charge is terminated.
MSTR+
during start-up charging, charging is cancelled.
MSTR-
ãNokia Corporation
CCS Technical Documentation
MSTR-
. By detection start-up charging is
. Battery low limit is
coff+
) charging is
MSTR+
Issue 1 11/02