Power-Down - Panasonic EB-GD93 Technical Manual

POWER SUPPLIES
Battery Voltage (V)
X (don't care)
X
<3.0
<3.5
>3.5
9.3.3. 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 nACC_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 nACC_SENSE.
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 is shown below. 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.
Issue 1
Revision 0
Temp Reading
invalid <VBAT + 0.4 V
invalid >VBAT + 0.4 V
X <VBAT + 0.4 V
valid <VBAT + 0.4 V
valid X
EXT_PWR nACC_SENSE
X X
>VBAT + 0.4 V X
>VBAT + 0.4 V X
>VBAT + 0.4 V <0.5 V
>VBAT + 0.4 V <0.5 V
EXT_PWR nACC_SENSE
X X
>VBAT + 0.4 V X
X X
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 FIQ. In this case, the
CPU only has time to perform a subset of the normal procedure. The priority is to pre-
vent corruption of SIM data.
Section 9
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EXT_PWR Result
Power-down (battery fault)
Sleep (battery fault)
Power-down (low battery)
LOW
OK
KBR0 ACC_PWR
1 1
1 1
0 1
0 1
0 1
Battery
KBR0
Condition
1 OK
1 LOW
0 OK
Description
Mode
active
restricted
charge
active or charge
restricted or charge
New Mode
active
restricted
active
MCUK001001G8
Technical Guide