DSB45 Development Support Box
Confidential / Released
s
DSB45_HD_V05
Page 14 of 50
01.02.2008
2.5
Turn on / off the GSM module
All the hardware driven solutions described in [1] for turning on and off the GSM module are
implemented on DSB45 and can be used by pressing the following keys:
2.5.1
Non-locking ignition key X132
The non-locking ignition key X132 starts up the GSM module. The IGT (ignition) signal of the
GSM module interface is grounded when the key is pressed for a duration specified in [1] to
activate the GSM module.
As an alternative to key X132, you can activate the ignition signal of the GSM module by
toggling the high-low state of the DTR0 line at COM1.
2.5.2
Non-locking emergency-off / power-off key X131
The X131 key can be assigned two functions, depending on the setting of the
EMERG-POWEROFF switch X141:
Emergency-off
•
As the name implies, the Emergency-off option is reserved only for use in case of
emergency. It should be used only exceptionally when, due to serious problems, the
software is not responding for more than 5 seconds. As specified in [1], pulling the
module’s EMERGOFF pin causes the loss of all information stored in the volatile memory
since power is cut off immediately.
•
The Emergency-off option is available on key X131 if the X141 switch is set to
“EMERGOFF” position as shown in Figure 3. Press the X131 key for at least 3.5s.
Power-off (for AC45 only)
•
The Power-off method is equivalent to the procedure initiated with AT^SMSO, i.e. data
will be saved before the module shuts down, and the module enters the POWER DOWN
mode. Note that this feature can be used only if your GSM module includes the
POWEROFF pin (see [1] for details).
•
The Power-off option is available only if the X141 key is set to “POWEROFF” position.
After Emergency-off or Power-off, the software can be restarted by pressing the ignition key
X132.
2.5.3
Turn off the GSM module using the AT^SMSO command
The best and safest approach to powering down the GSM module is using the AT
command AT^SMSO.
This procedure lets the GSM module log off from the network and allows the software to
enter a secure state and safe data before disconnecting the power supply. The mode is
referred to as POWER DOWN mode. A detailed description is provided in [1] and [2].
After using AT^SMSO, the software can be restarted by pressing the ignition key X132.
