LEA-M8F - Hardware Integration Manual
UBX-14000034 - R03
Early Production
Information
Hardware
description
Page 8 of 30
1.4
Connecting power
The u-blox LEA-M8F module has three power supply pins:
VCC
,
V_BCKP
and
VDD_USB
.
1.4.1
VCC
The
VCC
pin provides the main supply voltage. During operation, the current drawn by the module can vary by
some orders of magnitude. For this reason, it is important that the supply circuitry be able to support the peak
power for a short time. For specification see the
LEA-M8F Data Sheet
Use a proper GND concept with preferably low ESR decoupling capacitors at the module supply input.
Do not use any resistors or coils in the power line.
1.4.2
V_BCKP
This pin must be connected to the main module supply VCC.
1.4.3
VCC_RF
The
VCC_RF
pin provides a filtered source of DC to power an active antenna or external LNA. For more
information, see section 2.2.
1.5
Interfaces
The following interfaces are available for communication with a host for control and data handling.
1.5.1
UART
The LEA-M8F module includes a Universal Asynchronous Receiver Transmitter (UART) serial interface
RxD/TxD
supporting configurable baud rates. See the
LEA-M8F Data Sheet
[1] for the supported baud rates.
The signal input and output levels are 0 V to
VCC
with inverted logic. An interface based on RS232 standard
levels (+/- 12 V) can be implemented using level shifters such as a Maxim MAX3232.
The interface does not support hardware handshake signals or synchronous operation.
Designs must allow access to the UART and the
SAFEBOOT_N
pin for future service, updates and
reconfiguration.
1.5.2
USB
A USB 2.0 (Full Speed, 12 Mb/s) compatible interface is available for communication as a development option.
The module is not designed to use the USB interface in an operational sense as the message latency cannot be
guaranteed.
The
USB_DP
pin has a pull-up resistor to signal a full-speed device to the USB host. The
VDD_USB
pin requires
connection to a 3 V (nom.) source to enable the USB interface. If the USB interface is not used, connect
VDD_USB
to GND.
u-blox provides Microsoft® certified USB drivers for Windows XP, Windows Vista, Windows 7 and Windows 8
operating systems. These drivers are available for down-load at our website: www.u-blox.com
The USB port is for non-operational use e.g. for evaluation or firmware down-load
