Integration Manual

TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R04 Advance Information Design-in
Page 108 of 141
2.8 General Purpose Input/Output
GPIOs are not supported by the TOBY-L2x0-00S product version except for the Wireless Wide Area
Network status indication configured on the GPIO1 pin: the pins should be not driven by any external
device.
GPIOs are not available on MPCI-L2 series modules.
2.8.1.1 Guidelines for TOBY-L2 series GPIO circuit design
A typical usage of TOBY-L2 modules’ GPIOs can be the following:
 Network indication provided over GPIO1 pin (see Figure 61 / Table 40 below)
 GNSS supply enable provided over GPIO2 (see Figure 57 / Table 36 or Figure 59 / Table 38 in section 2.6.3)
 GNSS data ready provided over GPIO3 (see Figure 57 / Table 36 or Figure 59 / Table 38 in section 2.6.3)
 GNSS RTC sharing provided over GPIO4 (see Figure 57 / Table 36 or Figure 59 / Table 38 in section 2.6.3)
 SIM card detection provided over GPIO5 (see Figure 46 / Table 30 or Figure 47 / Table 31 in section 2.5)
 Clock output provided over GPIO6 (see Figure 60 / Table 39 in section 2.7.1)
TOBY-L2 series
GPIO1
R1
R3
3V8
Network Indicator
R2
21
DL1
T1
Figure 61: Application circuit for network indication provided over GPIO1
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 40: Components for network indication application circuit
Use transistors with at least an integrated resistor in the base pin or otherwise put a 10 k resistor on the
board in series to the GPIO of TOBY-L2 modules.
Do not apply voltage to any GPIO of TOBY-L2 before the switch-on of the GPIOs supply (V_INT), to avoid
latch-up of circuits and allow a proper module boot. If the external signals connected to the module
cannot be tri-stated or set low, insert a multi channel digital switch (e.g. TI SN74CB3Q16244, TS5A3159,
TS5A63157) between the two-circuit connections and set to high impedance before V_INT switch-on.
ESD sensitivity rating of the GPIO pins is 1 kV (Human Body Model according to JESD22-A114).
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 the GPIO pins are not used, they can be left unconnected on the application board.
2.8.1.2 Guidelines for general purpose input/output layout design
The general purpose inputs / outputs pins are generally not critical for layout.