u-blox EVK-M91-00-01, Руководство пользователя

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EVK-M91 - User guide
2.
SPI – In this selection the EVK operates only with the SPI interface. RS-232 is switched off.
5.1.2 USB
The USB Type-C connector on the evaluation board can be used for both power supply and
communication. The easiest way to evaluate the EVK-M91 operation is to connect the EVK to a PC by
the USB-C 2.0 cable and then to use the u-center to configure and monitor the GNSS functions. The
USB connector has a direct connection to the u-blox M9 receiver, which enables the USB interface
to be used as a communication interface as well.
When the board is connected to the PC, Windows creates a virtual COM port to the PC. This
newly created virtual COM port needs then to be selected on the u-center application. The USB
communication speed is by default set to 38400 baud. EVK-M91 supports speeds up to 921600
baud.
5.1.3 UART
The evaluation unit includes two options for the UART connection, one is an RS-232 port for serial
communication with the PC and the other one is the 14-pin connector.
5.1.3.1 RS-232
Connect using a straight RS-232 serial cable with male and female connectors to the port on your
PC. The maximum cable length is < 3.0 meters. To configure the RS-232 port, use the UBX-CFG-
VALSET command and select CFG-UART1 Configuration group in the u-center application. The
maximum operating baud rate is 921600 Bd. If you are using a USB to RS-232 adaptor cable, you
can connect it directly to the evaluation kit RS-232 port.
The 9-pin RS-232 female connector is assigned as listed below:
Pin no. Assignment
1 & 6 Time pulse
2 TXD/SPI_MISO, GNSS Transmit Data, serial data to external
device
3 RXD/SPI_MOSI, GNSS Receive Data, serial data from
external device
4 EXTINT
5 GND
7, 8 & 9 not connected
Table 4: EVK-M91 RS-232 connector pin description
5.1.3.2 14-pin connector
There is a 14-pin connector on the EVK-M91. It provides PIO, interfaces and supply options. All these
pins are ESD protected. The 14-pin connector can be used for interfacing with UART, SPI, I2C and
for evaluating other advanced scenarios.
Pin no. Pin name I/O Level Description
14 V5 IN I 4.75-5.25 V Power input – can be used instead of USB
13 GNSS I2 O 5.0 V Supply current measurement (total current) node 2. See
description for pin 12.
12 GNSS I1 O 5.0 V Supply current measurement (total current) node 1.
Connected to 5 V power supply. Current measured over a
1
Ω
1% resistor between pins 12 (GNSS I1) and 11 (GNSS
I2). Pin 12 (GNSS I1) is at higher potential. NOTE: the total
current includes also LNA and SPI flash.
UBX-19056858 - R04 5 Device description Page 11 of 27
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