Power-Up - Panasonic EB-G450 Technical Manual

POWER SUPPLIES

Signal

EXTINT

STAY_ALIVE

nPOW_ON

SIM_PWR

nIGNITION

9.3

The power-up procedure has two phases: There is an initial check to see if the battery is in good condition. If

successful, the second phase determines the source of the power-up request, key press, external power,

accessory etc. and acts accordingly.

The phone can be defined as powered-on whenever the linear regulators are active. It is not always obvious to the

user that the phone is powered-on as it may be in one of four modes.

In this mode the CPU has been prevented from deactivating the linear regulators by EXT_PWR.

Sleep

There is no CPU activity

Charge

The CPU is alive but may only perform battery charging functions and monitor the power key.

Restricted

LEDs light, beeps, can charge battery etc. but it is not permitted to use the radio.

Active

The mobile is fully functional; LEDs light, beeps, search for network etc.

9.3.1 Battery Condition

The CPU must check the battery condition before deciding to power-up. The CPU can measure battery voltage and

temperature. If the temperature measurement is invalid, giving a ridiculous temperature reading; a non-standard

battery has been fitted, the battery is missing or the whole phone is operating far outside its specified temperature

range. In any of these cases the phone must not power up. The CPU will regularly monitor the battery condition

while the phone is on.

If EXT_PWR is present the regulators will be forced on and the CPU will not be able to deactivate them. If the CPU

wants to power-down, all it can do is to enter sleep mode.

Battery Voltage (V)

X (don't care)

X

<4.0

<4.0

>4.0

Issue 1

Revision 0

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CPU I/O

Description

External interrupt to the CPU. The voltage detector output goes LOW when

the battery voltage drops below 3.6V. If the phone is on, this signal forces

I

the PSU off and the interrupt initiates an emergency power down procedure.

If the phone is off, a LOW on this signal will lock the PSU off. EXTINT can

override all signals except EXT_PWR

O

Signal generated by the CPU to hold the PSU on. Active high

NC

Chip select to the 3.0 and 3.6V regulators. Active low

O

Output from the CPU to enable the SIM 5.0V supply. Active high

Vehicle ignition. When the vehicle ignition is on, this signal is LOW. This is

I

sensed by the CPU as an analogue voltage

Temp. reading

invalid

invalid

X

valid

valid

EXT_PWR_SENSE

0.5V

1.2V

<0.5V

1.2V

X

Section 9

9 - 2

Result

Power-down (battery fault)

Sleep (battery fault)

Power-down (low battery)

LOW

OK

MCUK971001G8

Technical Guide