Integration Manual

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SARA-R5 series - System integration manual
UBX-19041356 - R03 System description Page 25 of 123
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1.6.2.3 Switch-off sequence by PWR_ON input pin
Figure 15 describes the switch-off sequence of the modules started by the PWR_ON input pin,
allowing storage of parameter settings in the non-volatile memory and a clean network detach:
When a low pulse with appropriate time duration is applied at the PWR_ON input pin (see the
SARA-R5 series data sheet [1]), the module starts the switch-off routine.
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
OFF
Tristate / Floating
ON
Operational -> Tristate
Operational
The module starts
the switch-off routine
VCC can be
removed
Figure 15: SARA-R5 series modules switch-off sequence by means of PWR_ON input pin
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.