Datasheet

LARA-R2 series - Data Sheet
UBX-16005783 - R15 Interfaces Page 12 of 48
2.3 System functions
2.3.1 Module power-on
LARA-R2 series modules can be switched on in one of the following ways:
 Rising edge on the VCC input to a valid voltage for module supply, i.e. applying module supply: the
modules switch on if the VCC supply is applied, starting from a voltage value of less than 2.1 V,
with a rise time from 2.3 V to 2.8 V of less than 4 ms, reaching a proper nominal voltage value
within VCC operating range.
Alternately, for example if the fast rise time on VCC rising edge cannot be guaranteed by the
application, the LARA-R2 series module can be switched on from not-powered mode as follows:
 RESET_N input pin is held low by the external application during the VCC rising edge, so that the
module will switch on when the external application releases the RESET_N input pin from the low
logic level, after the VCC supply voltage stabilizes at its proper nominal value within the operating
range
 PWR_ON input pin is held low by the external application during the VCC rising edge, so that the
module will switch on when the external application releases the PWR_ON input pin from the low
logic level, after the VCC supply voltage stabilizes at its proper nominal value within the operating
range
When the LARA-R2 series modules are in the power-off mode (i.e. properly switched off as described
in section 2.3.2, with valid VCC module supply applied), they can be switched on as following:
 Low pulse on the PWR_ON pin, which is normally set high by an internal pull-up, for a valid time
period (see section 4.2.8). The PWR_ON line should be driven by open drain, open collector or
contact switch.
 Rising edge on the RESET_N pin, i.e. releasing the pin from the low level, normally set high by an
internal pull-up. The RESET_N line should be driven by open drain, open collector or contact switch.
 RTC alarm, i.e. pre-programmed scheduled time by AT+CALA command.
2.3.2 Module power-off
LARA-R2 series can be properly switched off, saving current parameter settings in the module’s non-
volatile memory and performing a proper network detach, by:
 AT+CPWROFF command (see the u-blox AT Commands Manual [1]).
 Low pulse on the PWR_ON pin, which is normally set high by an internal pull-up, for a valid time
period (see section 4.2.8). The PWR_ON line should be driven by open drain, open collector or
contact switch.
An abrupt under-voltage shutdown occurs on LARA-R2 series modules when the VCC supply is
removed. If this occurs, it is not possible to store the current parameter settings in the module’s non-
volatile memory or to perform the proper network detach.
An abrupt shutdown occurs on LARA-R2 series modules when a low level is applied on the RESET_N
pin, which is normally set high by an internal pull-up. If this occurs, it is not possible to store the
current parameter settings in the module’s non-volatile memory and to perform the proper network
detach.
An over-temperature or an under-temperature shutdown occurs on LARA-R2 modules when the
temperature measured within the cellular module reaches the dangerous area, if the optional Smart
Temperature Supervisor feature is enabled and configured by the dedicated AT command. For more
details, see the LARA-R2 series System Integration Manual [2] and the u-blox AT Commands
Manual [1], +USTS AT command.