Integration Manual

Table Of Contents
SARA-R5 series - System integration manual
UBX-19041356 - R03 System description Page 24 of 123
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1.6.2 Module power-off
1.6.2.1 Switch-off events
SARA-R5 series modules can be gracefully switched off, triggering the storage of the current
parameter settings in the non-volatile memory of the module and performing a clean network detach
procedure, by:
+CPWROFF AT command (see SARA-R5 series AT commands manual [2]).
Forcing a low pulse on the PWR_ON pin (normally high due to internal pull-up) for a valid time
period (see the SARA-R5 series data sheet [1]).
A fast emergency shutdown procedure of the modules, without storage of the current parameter
settings in the module’s non-volatile memory and without proper network detach, can be triggered by:
Toggling the GPIO input pin configured with fast emergency shutdown function (see section 1.11)
An abrupt under-voltage shutdown occurs on SARA-R5 series modules when the VCC supply is
removed. If this occurs, it is not possible to perform the storing of the current parameter settings in
the module’s non-volatile memory or to perform the proper network detach.
It is highly recommended to avoid an abrupt removal of the VCC supply during SARA-R5 series
modules normal operations.
1.6.2.2 Switch-off sequence by +CPWROFF AT command
Figure 14 describes the switch-off sequence of the modules started by the +CPWROFF AT command,
allowing storage of parameter settings in the non-volatile memory and a clean network detach:
When the +CPWROFF AT command is sent the module starts the switch-off routine.
Then the module replies OK on the AT interface: the switch-off routine is in progress.
At the end of the switch-off routine, all the digital pins are tri-stated and all the internal voltage
regulators are turned off, including the generic digital interfaces supply (V_INT).
Then, the module remains in switch-off mode as long as a switch-on event does not occur
(e.g. applying a low level to PWR_ON), or enters not-powered mode if the VCC supply is removed.
VCC
PWR_ON
RESET_N
V_INT
Internal reset
System state
BB pads state Operational
OFF
Tristate / Floating
ON
Operational
Tristate
AT+CPWROFF
sent to the module
0 s
~2.5 s
~5 s
OK
replied by the module
VCC can be
removed
Figure 14: SARA-R5 series modules switch-off sequence by means of +CPWROFF AT command
The Internal Reset signal is not available on a module pin, but it is highly recommended to monitor
the V_INT pin to sense the end of the switch-off sequence.
The duration of each phase in the SARA-R5 series modules’ switch-off routines can largely vary,
depending on the application / network settings and the concurrent module activities.