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P7389i – Circuit Description
are present, but colder than –15 deg C and no card is inserted then the output of the
comparator Q905
will stay high and the unit will display 'Insert Card'. Once the
battery temperature goes above that
but the SIM card is either not inserted or faulty 'CHECK CARD ' will be displayed.
The reason behind this is to prevent the extra cost of a mechanical SIM presence
detect switch and to prevent the SIM card being removed whilst connected to Aux
Power.
Logic: Charger Circuit
As mentioned already the P3689 is not compatible with the mid rate charger. The
charging path therefore, is as the Kramer circuitry.
After the charger has been connected
of charger and therefore charging profile to be used.
EXT_B+
from
J600
Pin 14 is passed through current sense resistor
feedback for charging current rate and input current transient protection.
Charging current control is maintained by
that opens or closes the charging gate within
phasing.
The charge is then fed through
Logic: Deep Sleep Mode
Deep sleep mode is there to provide a facility to save battery life by intermittently
shutting off part of the PCB. This is achieved in the following way. The signal
STBY_DL
is generated from Whitecap Pin F1, through a standby delay circuit
CR912
and U906. The logic gate
short delay between the time of activation of the
STBY_DL
signal. This is a hardware patch for timing issues related to the
Whitecap's Deep Sleep Module (DSM). The resultant signal is then passed onto
Q834
and
Q912.
1) Grounding
VREF
2) Grounding
V2
This switches off MAGIC DM, Front END IC and inhibits the
Transmit path through
3) The shutdown is only for a fraction of a second and during that time the GCAP Clock
supports the logic side of the unit. The GCAP clock is generated by Y900, which
generates a 32.768MHz clock. This clock is output from Whitecap
directly to Whitecap Pin P4. The clock is always monitored by Whitecap and should
it fail, the unit will no longer go into deep sleep mode.
Logic: Keypad Operation
1) The keypad works as a matrix supported V2. The signals inform the Whitecap upon a
key press by dropping the signal 'low'. Below is the Key Matrix.
KBR0
KBR1
Motorola Internal Use
(BATT_THERM
MAN_TEST _AD
CHRGC
Q900
to
BATT+
U906
This has the effect respectively of:
which makes MAGIC DM inoperable
RF_V2
KBR2
KBR3
KBR4
Voltage approximately 2.51V)
will be read, to decide on type
(GCAP II
Pin E8). It is this 'drive'
Q900 Charging
FET. The drive is set during
and diode
CR912
are used to provide a
STBY_PC5
KBC0
KBC1
13
R913
this is used as
signal and to the
Pin C7
and fed
KBC2
KBC3
KBC4
GND
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