LISA-U series - System Integration Manual
UBX-13001118 - R17
Advance information
System description
Page 115 of 190
The logic level of the pin configured to provide module status indication, that is set high when the module is
switched on (with interfaces configured) and low when the module is switched off, is inverted by a transistor
biased by the
V_BCKP
supply, which is generated by the module when a valid
VCC
is applied.
A pull-down resistor is provided at the
GPIO1
output (which provides module status indication) to fix a low level
at inverting transistor input when
GPIO1
is floating, i.e. when the module is switched off, so that high logic level
is present at the application processor input when the module is switched off and low logic level when the
module is switched on (i.e. the opposite logic level of the GPIO).
Input (1.8V)
V_BCKP
2
LISA-U2 series
(except LISA-U200-00S)
Application
Processor
R1
R3
Module Status Indication
R2
20
GPIO1
T1
Figure 60: Module status indication application circuit
Reference
Description
Part Number - Manufacturer
R1, R3
47 k
Ω
Resistor 0402 5% 0.1 W
Various manufacturers
R2
100 k
Ω
Resistor 0402 5% 0.1 W
Various manufacturers
T1
NPN BJT Transistor
BC847 - Infineon
Table 50: Components for module status indication application circuit
