LEA-M8S / LEA-M8T - Hardware integration manual
UBX-15030060 - R06
Hardware description
Page 6 of 33
Production information
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If no backup supply voltage is available, connect the V_BCKP pin to VCC.
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As long as the LEA-M8S and LEA-M8T modules are supplied via the VCC, the backup battery is
disconnected from the RTC and the BBR to avoid unnecessary battery drain (see Figure 1). In this
case, VCC supplies power to the RTC and BBR.
Figure 1: Backup battery and voltage (for exact pin orientation, see the LEA-M8S Data sheet [1] and the NEO/LEA-M8T Data
sheet
1.3.3
VDD_USB: USB interface power supply
VDD_USB supplies the USB interface. If the USB interface is not used, the VDD_USB pin must be
connected to GND. For more information about correctly handling the VDD_USB pin, see section 1.4.
1.3.4
VCC_RF: Output voltage RF section
The VCC_RF pin can supply an active antenna or external LNA. For more information, see section 2.4.
1.3.5
V_ANT: Antenna supply
The V_ANT pin is available to provide antenna bias voltage to supply an optional external active
antenna. For more information, see section 2.4.
☞
If not used, connect the V_ANT pin to GND.
1.4
Interfaces
1.4.1
UART
The LEA-M8S and LEA-M8T positioning modules include a universal asynchronous receiver
transmitter (UART) serial interface RXD/TXD, which supports configurable baud rates. The baud
rates supported are specified in the LEA-M8S Data sheet [1] and the NEO / LEA-M8T Data sheet [2]
The signal output and input levels are 0 V to VCC. An interface based on RS232 standard levels
(+/- 12 V) can be implemented using level shifters such as Maxim MAX3232. Hardware handshake
signals and synchronous operation are not supported.
1.4.2
USB
A USB version 2.0 FS (full speed, 12 Mb/s) compatible interface is available for communication as an
alternative to the UART. The USB_DP integrates a pull-up resistor to signal a full-speed device to the
host. The VDD_USB pin supplies the USB interface.
u-blox provides Microsoft® certified USB drivers for Windows Vista, Windows 7, Windows 8 and
Windows 10 operating systems. These drivers are available at our website at
USB external components
