LISA-U1 series - System Integration Manual
3G.G2-HW-10002-3
Preliminary
System description
Page 65 of 125
The pin must be connected to the active-high enable pin (or the active-low shutdown pin) of the voltage
regulator that supplies the u-blox GPS receiver on the application board.
The “GPS supply enable” function improves the power consumption of the GPS receiver. When the GPS
functionality is not required, the GPS receiver can be completely switched off by the wireless module that is
controlled by the application processor with AT commands.
The application circuit for the connection of a LISA-U1 series wireless module to a u-blox 1.8 V GPS receiver is
illustrated in Figure 36. A pull-down resistor is mounted on the
GPIO2
line to avoid a switch on of the GPS
module when the LISA-U1 series module is in the internal reset state.
Functions supported by upcoming FW version
LISA-U1 series
R1
IN
OUT
GND
GPS LDO
Regulator
SHDN
u-blox
1.8 V GPS receiver
SDA2
SCL2
R2
1V8
1V8
VMAIN
1V8
U1
21
GPIO2
SDA
SCL
C1
TxD1
EXTINT0
GPIO3
GPIO4
46
45
23
24
VCC
R3
Figure 36: DDC Application circuit for u-blox 1.8 V GPS receiver
Reference
Description
Part Number - Manufacturer
R1, R2
4.7 k
Ω
Resistor 0402 5% 0.1 W
RC0402JR-074K7L - Yageo Phycomp
R3
47 k
Ω
Resistor 0402 5% 0.1 W
RC0402JR-0747KL - Yageo Phycomp
U1
Voltage Regulator for GPS Receiver
See GPS Receiver Hardware Integration Manual
Table 25: Components for DDC application circuit for u-blox 1.8 V GPS receiver
If a 3 V u-blox GPS receiver is used, the
SDA
,
SCL
pins of the LISA-U1 series wireless module cannot be directly
connected to the 3 V u-blox GPS receiver. An application circuit for the connection of a LISA-U1 series wireless
module to a u-blox 3.0 V GPS receiver is illustrated in Figure 37. A pull-down resistor is mounted on the
GPIO2
line to avoid a switch on of the GPS module when the LISA-U1 series module is in the internal reset state.
