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POWER SUPPLIES
9.3.2 Power-up Sequence
The power-up sequence can be initiated by pressing the power key, or by applying a power source to the EXT_PWR signal
line. Both enable the linear regulators and the CPU becomes active. The CPU must then check the battery condition; if the
phone is not required to power-down or sleep immediately, the result must be OK or LOW. The CPU then checks to see if a
hands-free unit is connected by polling the nHF_SENSE signal, LOW when HF is connected.
Now the CPU can determine whether to remain powered-up or not, according to the truth-table shown below. In each case the
active parameters are shaded.
Battery Condition
OK
LOW
OK or LOW
OK
LOW
With a hands-free unit connected, the phone can be configured via the MMI to power-up and down with transitions of the vehicle
ignition. These are sensed by the CPU on nIGNITION, LOW when the ignition is on.
Any other state than those in the table will cause the phone to deactivate the PSU by setting STAY_ALIVE LOW.
While the CPU is active, it must monitor the battery condition and accessory connectivity and change state accordingly.
Current Mode
Charge
Charge
Restricted
9.4 Power-down
There are two power-down procedures:
Procedure
Normal power-down
Emergency power-down
The truth-table for the power state transitions are shown below, the cause of a transition is shaded. In some cases the phone
does not power-down completely but may enter a state of reduced functionality, e.g. from active to charge mode.
When the new mode is OFF or sleep, the CPU will set STAY_ALIVE LOW.
Current mode
X
X
X
active
active
active
active
active
active
active
active
active
active
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HF
nEXT_PWR
X
X
X
>1.2 V
no
>1.2 V
yes
>1.2 V
yes
>1.2 V
HF
nEXT_PWR
X
X
X
1.2 V
X
X
Description
In this case, the software has full control over the power-down procedure. Calls can be
terminated gracefully etc. In some cases the PSU is not deactivated but there is a
change of operating mode.
This situation is caused by battery removal and is flagged by EXTINT. In this case the
CPU only has time to perform a subset of the normal procedure. The priority is to
prevent corruption of SIM data.
Battery Voltage
HF
nIGNITION
X
X
X
X
X
X
X
X
<3.5 V
X
X
<3.5 V
no
X
<3.5 V
yes
>2.5 V
<3.5 V
yes
<0.5 V
<3.5 V
yes
>2.5 V
X
no
X
X
yes
<0.5 V
X
yes
>2.5 V
X
yes
>2.5 V
X
X
X
nIGNITION
KBR0
LOGIC_PWR
X
1
1
X
1
1
X
0
1
<0.5 V
0
1
<0.5 V
0
1
nIGNITION
KBR0
Battery Condition
X
1
OK
X
1
LOW
X
0
OK
EXTINT
KBR0
nEXT_PWR
1
X
<0.5 V
0
X
X
1
1
<0.5 V
1
0
>1.2 V
1
1
>1.2 V
1
1
X
1
1
>1.2 V
1
0
X
1
1
>1.2 V
1
1
>1.2 V
1
1
X
1
0
>1.2 V
1
0
<0.5 V
Section 9
– 34 –
Mode
active
restricted
charge
active or charge
restricted or charge
New Mode
active
restricted
active
power-down
New mode
normal
OFF
emergency
OFF
normal
OFF
normal
restricted
normal
charge
normal
OFF
normal
charge
normal
OFF
normal
charge
normal
charge
normal
OFF
normal
OFF
normal
OFF
MCUK990801G8
Technical Guide
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