Ublox LEA-M8S - 2 Design; Pin Description

LEA-M8S / LEA-M8T - Hardware integration manual
UBX-15030060 - R06 Design Page 11 of 33
Production information
2 Design
2.1 Pin description
Function
Pin
No.
I/O
Description
Remarks
Power
VCC
6
I
Supply voltage
Provide clean and stable supply.
GND
7, 13, 14,
15, 17
-
Ground
Assure a good GND connection to all GND pins of
the module.
VCC_OUT
8
O
Output voltage (VCC)
Leave open if not used.
V_BCKP
11
I
Backup supply voltage
It is recommended to connect a backup supply
voltage to V_BCKP in order to enable warm and
hot start features on the positioning modules.
Otherwise, connect to VCC.
VDD_USB
24
I
USB power supply
To use the USB interface connect this pin to 3.0 –
3.6 V.
If no USB serial port used connect to GND.
Antenna
RF_IN
16
I
GNSS signal input from
antenna
Use a controlled impedance transmission line of
50  to connect to RF_IN.
VCC_RF
18
O
Output voltage RF
section
Can be used to power external LNA or an external
active antenna (VCC_RF connected to V_ANT
with 10 ). The max power consumption of the
antenna must not exceed the data sheet
specification of the module. Leave open if not
used.
V_ANT
19
I
Antenna bias voltage
Connect to GND (or leave open) if passive antenna
is used. If an active antenna is used, add a 10 
resistor in front of V_ANT input to the antenna
bias voltage or VCC_RF.
EXTINT1
20
I
Ext. interrupt
Ext. interrupt pin. Int. pull-up resistor to VCC. Can
be configured as open circuit detection
(ANT_DET_N). Leave open if not used.
UART
TXD 3
(LEA-M8S)
TXD / SPI MISO
(LEA-M8T)
O
TXD
Serial port TXD
O
TXD
SPI MISO
Serial port TXD if D_SEL =1 (or open)
SPI MISO if D_SEL = 0
RXD 4
(LEA-M8S)
RXD / SPI MOSI
(LEA-M8T)
I
RXD
Serial port if RXD
I
RXD
SPI MOSI
Serial port if RXD D_SEL =1 (or open)
SPI MOSI if D_SEL = 0
USB
USB_DM
25
I/O
USB I/O line
USB2.0 bidirectional communication pin. Leave
open if unused. For implementations, see section
1.4.
USB_DP
26
I/O
USB I/O line
System
RESET_N
10
I
Hardware Reset
(Active Low)
Leave open if not used. Do not drive high.
TIMEPULSE
28
O
Timepulse 1
Configurable timepulse 1 signal (one pulse per
second by default). Leave open if not used.
TP2/SAFEBOOT_
N
(LEA-M8T)
SAFEBOOT_N
(LEA-M8S)
12
I/O
Safeboot_N / Timepulse
2
Configurable timepulse signal. Must not be held
LO during start-up.
I/O
Safeboot_N
Must not be held LO during start-up.
EXTINT0 / PIO13
27
I /
(O)
Ext. interrupt / PIO13
Ext. interrupt pin. Int. pull-up resistor to VCC.
Leave open if unused. The pin can also be used as
a generic PIO (PIO13).