LISA-U1 series - System Integration Manual
3G.G2-HW-10002-3
Preliminary
System description
Page 66 of 125
LISA-U1 series
R1
IN
OUT
GND
GPS LDO
Regulator
SHDN
u-blox
3.0 V GPS receiver
R2
VMAIN
3V0
U1
21
GPIO2
46
SDA
45
SCL
R4
R5
1V8
SDA1
SDA2
GND
U2
SCL1
SCL2
VREF1
VREF2
I2C-bus
Bidirectional
Voltage Translator
21
V_INT
C1
C2
C3
R3
23
GPIO3
24
GPIO4
1V8
A1
B1
GND
U3
A2
B2
VCCA
VCCB
Generic
Bidirectional
Voltage Translator
C4
C5
3V0
SDA2
SCL2
TxD1
EXTINT0
VCC
Functions supported by upcoming FW version
Figure 37: DDC Application circuit for u-blox 3.0 V GPS receiver
Reference
Description
Part Number - Manufacturer
R1, R2, R4, R5
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
C2, C3, C4, C5
100 nF Capacitor Ceramic X5R 0402 10% 10V
GRM155R71C104KA01 - Murata
U1
Voltage Regulator for GPS Receiver
See GPS Receiver Hardware Integration Manual
U2
I2C-bus Bidirectional Voltage Translator
PCA9306DCURG4 - Texas Instruments
U3
Generic Bidirectional Voltage Translator
TXB0104PWR - Texas Instruments
Table 26: Components for DDC application circuit for u-blox 3.0 V GPS receiver
The following functions will be available in the upcoming FW version of LISA-U1 series modules:
GPIO3
pin will provide the “GPS data ready” function (parameter <gpio_mode> of AT+UGPIOC command set
to 4 by default), to sense when the u-blox GPS receiver connected to the wireless module is ready to send data
by the DDC (I2C) interface. The pin will be set as
Input, to sense the line status, waking up the wireless module from idle-mode when the u-blox GPS receiver
is ready to send data by the DDC (I
2
C) interface, if the parameter <mode> of +UGPS AT command is set to 1
and the parameter <GPS_IO_configuration> of +UGPRF AT command is set to 16
Tri-state with an internal active pull-down enabled, otherwise (default setting)
The pin that provides the “GPS data ready” function must be connected to the data ready output of the u-blox
GPS receiver (i.e. the pin TxD1 of the u-blox GPS receiver) on the application board.