Ublox SARA-N210, System Integration Manual

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SARA-N2 series - System Integration Manual
UBX-17005143 - R06 Design-in Page 49 of 82
2.6.3 DDC (I 2 C) interface
☞
DDC (I 2 C) interface is not supported by the "02" version of the product.
2.7 General Purpose Input/Output (GPIO)
A typical usage of SARA-N2 series modules’ GPIOs follows:
 GPIO1 pin providing secondary UART data output, available to collect trace diagnostic logs
delivered by the module: it is recommended to provide a direct access to the GPIO1 pin by means
of an accessible testpoint for diagnostic purposes (see sections
1.9.2 and 2.6.2 )

CTS pin set as Network Indicator (see Figure 29 / Table 23 below) or Ring Indicator (see section
2.6.1.1 )
SARA-N2 series
CTS
R1
R3
3V6
Network Indicator
R2
11
DL1
T1
TestPoint
GPIO1
16
Secondary UART for Diagnostic
Figure 29: Application circuit for network indication provided over CTS
Reference Description Part Number - Manufacturer
R1 10 k  resistor 0402 5% 0.1 W Various manufacturers
R2 47 k  resistor 0402 5% 0.1 W Various manufacturers
R3
820  resistor 0402 5% 0.1 W
Various manufacturers
DL1 LED red SMT 0603 LTST-C190KRKT - Lite-on Technology Corporation
T1 NPN BJT Transistor BC847 - Infineon
Table 23: Components for network indication application circuit
☞
Use transistors with at least an integrated resistor in the base pin or otherwise put a 10 k
Ω
resistor
on the board in series to the GPIO of SARA-N2 series modules.
☞
Do not apply voltage to any GPIO of the module before the switch-on of the GPIO’s supply (V_INT),
to avoid latch-up of circuits and allow a proper boot of the module.
☞
ESD sensitivity rating of the GPIO pins is 1 kV (Human Body Model according to JESD22-A114).
A higher protection level could be required if the lines are externally accessible and it can be
achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to
accessible points.
☞
If GPIO pins are not used, they can be left unconnected on the application board, but it is
recommended to provide direct access to the GPIO1 pin by means of accessible testpoints for
diagnostic purposes.
2.8 Reserved pins (RSVD)
SARA-N2 series modules have pins reserved for future use, marked as RSVD.
All the RSVD pins are to be left unconnected on the application board, except for the RSVD pin number
33 that can be externally connected to ground.