Data Sheet

NEO-M8P - Data Sheet

UBX-15016656 - R06 Early Production Information Functional description

Page 14 of 30

1.15.1 UART

The NEO-M8P modules include one UART interface, which can be used for communication to a host. It supports

configurable baud rates. For supported baud rates see the u-blox 8 / u-blox M8 Receiver Description Including

Protocol Specification [2].

Designs must allow access to the UART and the SAFEBOOT_N function pin for future service, updates and

reconfiguration.

1.15.2 USB

A USB version 2.0 FS compatible interface can be used for communication as an alternative to the UART. The

pull-up resistor on pin USB_DP is integrated to signal a full-speed device to the host. The VDD_USB pin supplies

the USB interface.

u-blox offers USB drivers for use with Windows operating systems. For Windows 7, 8 and 10 there is a sensor

driver for users who wish to connect to the Windows sensor platform. For users who wish to connect multiple

devices or require a virtual com port, Windows 10 users can use the built-in driver, otherwise u-blox provide a

standard USB driver (CDC-ACM) for Windows Vista and Windows 7 and 8. Windows drivers can be down-

loaded from the u-blox.com web site.

1.15.3 SPI

The SPI interface is designed to allow communication to a host CPU. The interface can be operated in slave

mode only. The maximum transfer rate using SPI is 125 kB/s and the maximum SPI clock frequency is 5.5 MHz.

Note that SPI is not available in the default configuration, because its pins are shared with the UART and DDC

interfaces. The SPI interface can be enabled by connecting D_SEL (Pin 2) to ground (see section 3.1).

1.15.4 Display Data Channel (DDC)

An I

C compliant DDC interface is available for communication with an external host CPU or u-blox cellular

modules. The interface can be operated in slave mode only. The DDC protocol and electrical interface are fully

compatible with Fast-Mode of the I

C industry standard. Since the maximum SCL clock frequency is 400 kHz, the

maximum transfer rate is 400 kb/s.

1.16 EXTINT: External interrupt

EXTINT is an external interrupt pin with fixed input voltage thresholds with respect to VCC. It can be used for

control of the receiver or for aiding.

For more information about how to implement and configure these features, see the u-blox 8 / u-blox M8

Receiver Description including Protocol Specification [2] and the NEO-M8P Hardware Integration Manual [1].

1.17 Clock generation

1.17.1 Oscillators

The NEO-M8P GNSS modules incorporate a TCXO for accelerated weak signal acquisition, faster start and

reacquisition. These TCXOs are carefully selected and screened for stability and against frequency perturbations

across the full operating range (–40° to +85°C).

1.17.2 Real-Time Clock (RTC)

The RTC is driven by a 32 kHz oscillator using an RTC crystal. If the main supply voltage fails, and a battery is

connected to V_BCKP, parts of the receiver switch off, but the RTC still runs providing a timing reference for the

receiver. This operating mode is called Hardware Backup Mode, which enables all relevant data to be saved in

the backup RAM to allow a hot or warm start later.