LARA-R2 series - System Integration Manual
UBX-16010573 - R02
Objective Specification
System description
Page 27 of 148
1.6
System function interfaces
1.6.1
Module power-on
When the LARA-R2 series modules are in the not-powered mode (switched off, i.e. the
VCC
module supply is
not applied), they can be switched on as following:
Rising edge on the
VCC
input pins to a valid voltage for module supply: the modules switch on if the
VCC
supply is applied with a rise time of less than 10 ms from 2.1 V to 3.0 V, reaching a proper nominal voltage
value within the
VCC
operating range.
Alternately, in case for example the fast rise time on
VCC
rising edge cannot be guaranteed by the application,
LARA-R2 series modules can be switched on from not-powered mode as following:
RESET_N
input pin is held low by the external application during the
VCC
rising edge, so that the modules
will switch on when the external application releases the
RESET_N
input pin from the low logic level after
that 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 modules
will switch on when the external application releases the
PWR_ON
input pin from the low logic level after
that 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. switched off 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: the
modules start the internal power-on sequence when the external application releases the
PWR_ON
pin from
the low logic level after that it has been set low for an appropriate time period
Rising edge on the
RESET_N
pin, i.e. releasing the pin from the low level, as that the pin is normally set high
by an internal pull-up: the modules start the internal power-on sequence when the external application
releases the
RESET_N
pin from the low logic level
RTC alarm, i.e. pre-programmed alarm by AT+CALA command (see
u-blox AT Commands Manual
As described in Figure 12, the LARA-R2 series
PWR_ON
input is equipped with an internal active pull-up resistor
to the
V_BCKP
supply: the
PWR_ON
input voltage thresholds are different from the other generic digital
interfaces. Detailed electrical characteristics are described in
LARA-R2 series
Data Sheet
Baseband
Processor
15
PWR_ON
LARA-R2 series
2
V_BCKP
Power-on
Power
Management
Power-on
10k
Figure 12: LARA-R2 series PWR_ON input description
