Cinterion EGS5, Hardware Interface Description

Page: 32 / 123

EGS5 Hardware Interface Description
3.3 Power Up / Power Down Scenarios
75
EGS5_HD_v02.004 Page 32 of 123 2012-02-09
Confidential / Released

3.3.1.2 Configuring the IGT Line for Use as ON/OFF Switch
The IGT line can be configured for use in two different switching modes: You can set the IGT
line to switch on the module only, or to switch it on and off. The switching mode is determined
by the parameter "MEShutdown/OnIgnition" of the AT^SCFG command. This approach is use-
ful for application manufacturers who wish to have an ON/OFF switch installed on the host de-
vice.
By factory default, the ON/OFF switch mode of IGT is disabled:
To configure IGT for use as ON/OFF switch:
We strongly recommend taking great care before changing the switching mode of the IGT line.
To ensure that the IGT line works properly as ON/OFF switch it is of vital importance that the
following conditions are met.
Switch-on condition:If the EGS5 is off, the IGT line must be asserted for at least 400ms before
being released. The module switches on after 400ms.
Switch-off condition: If the EGS5 is on, the IGT line must be asserted for at least 1s before
being released. The module switches off after the line is released. The
switch-off routine is identical with the procedure initiated by AT^SMSO, i.e.
the software performs an orderly shutdown as described in
Section
3.3.3.1 . Before switching off the module wait at least 2 seconds after
startup.
Figure 7:
Timing of IGT if used as ON/OFF switch
3.3.1.3 Turn on EGS5 Using the VCHARGE Signal
As detailed in Section 3.5.6 , the charging adapter can be connected regardless of the module’s
operating mode.
If the charger is connected to the charger input of the external charging circuit and the module’s
VCHARGE line while EGS5 is off, and the battery voltage is above the undervoltage lockout
threshold, processor controlled fast charging starts (see
Section 3.5.5 ). EGS5 enters a restrict-
ed mode, referred to as Charge-only mode where only the charging algorithm will be launched.
During the Charge-only mode EGS5 is neither logged on to the GSM network nor are the serial
at^scfg=meshutdown/onignition
^SCFG: "MEShutdown/OnIgnition","off"
OK
# Query the current status of IGT.
# IGT can be used only to switch on EGS5.
IGT works as described in Section 3.3.1.1 .
at^scfg=meshutdown/onignition
^SCFG: "MEShutdown/OnIgnition","on"
OK
# Enable the ON/OFF switch mode of IGT.
# IGT can be used to switch on and off EGS5.