TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R07
Advance Information
Design-in
Page 119 of 158
2.8
General Purpose Input/Output
GPIOs are not supported by TOBY-L2 “00”, “01”, and “50” product versions, except for the WWAN
status indication configured on
GPIO1
of “00”, “01” product versions and the Wi-Fi enable function
configured on
GPIO1
of “50” product version: the pins should not be 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 67 / Table 42 below)
GNSS supply enable provided over
GPIO2
(see Figure 62 / Table 37 or Figure 64 / Table 39 in section 2.6.3)
GNSS data ready provided over
GPIO3
(see Figure 62 / Table 37 or Figure 64 / Table 39 in section 2.6.3)
GNSS RTC sharing provided over
GPIO4
(see Figure 62 / Table 37 or Figure 64 / Table 39 in section 2.6.3)
SIM card detection provided over
GPIO5
(see Figure 51 / Table 31 or Figure 52 / Table 32 in section 2.5)
Clock output provided over
GPIO6
(see Figure 66 / Table 41 in section 2.7.1)
TOBY-L2 series
GPIO1
R1
R3
3V8
Network Indicator
R2
21
DL1
T1
Figure 67: 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 42: 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.
