LISA-U2 series - System integration manual
UBX-13001118 - R27
Features description
Page 154 of 183
C1-Public
The application processor can start an SAP connection negotiation between the LISA-U2 module SAP
client and an SAP server using a custom AT command (for more details, see the u-blox AT commands
manual
While the connection with the SAP server is not fully established, the LISA-U2 module continues to
operate with the attached (local) SIM, if present. Once the connection is established and negotiated,
the LISA-U2 module performs a detach operation from the local SIM followed by an attach operation
to the remote one. Then the remotely attached SIM is used for any GSM/UMTS network operation.
URC indications are provided to inform the user about the state of both the local and remote SIM. The
insertion and the removal of the local SIM card are notified if a proper card presence detection circuit
using the
GPIO5
of LISA-U2 modules is implemented as shown in the section
, and if the related
“SIM card detection” and “SIM hot insertion/removal” functions are enabled by AT commands (for
more details, see the u-blox AT commands manual
, +UGPIOC, +UDCONF=50 AT commands).
Upon SAP deactivation, the LISA-U2 modules perform a detach operation from the remote SIM
followed by an attach operation to the local one, if present.
3.18
Smart Temperature Management
Cellular modules
–
independent of the specific model
–
always have a well-defined operating
temperature range. This range should be respected to guarantee full device functionality and long life
span.
Nevertheless there are environmental conditions that can affect the operating temperature, e.g. if
the device is located near a heating/cooling source, if there is/isn’t air circulating, etc.
The module itself can also influence the environmental conditions; such as when it is transmitting at
full power. In this case, its temperature increases very quickly and can raise the temperature nearby.
The best solution is always to properly design the system where the module is integrated.
Nevertheless, an extra check/security mechanism embedded into the module is a good solution to
prevent operation of the device outside of the specified range.
3.18.1
Smart Temperature Supervisor (STS)
The Smart Temperature Supervisor is activated and configured by a dedicated AT+USTS command.
See the u-blox AT commands manual
for more details.
The cellular module measures the internal temperature (Ti) and its value is compared with predefined
thresholds to identify the actual working temperature range.
☞
Temperature measurement is done inside the cellular module: the measured value could be
different from the environmental temperature (Ta).
Warning
area
t
-1
t
+1
t
+2
t
-2
Valid temperature range
Safe
area
Dangerous
area
Dangerous
area
Warning
area
Figure 72: Temperature range and limits
