Data Sheet

NEO-7 - Data Sheet

UBX-13003830 - R04 Early Production Information Functional description

Page 11 of 26

1.11 Interfaces

A number of interfaces are provided either for data communication or memory access. The embedded firmware

uses these interfaces according to their respective protocol specifications.

1.11.1 UART

NEO-7 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 7 Receiver Description Including Protocol

Specification [2].

1.11.2 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 provides a Microsoft

certified USB driver for Windows XP, Windows Vista and Windows 7 operating

systems.

1.11.3 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 1 Mb/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).

1.11.4 Display Data Channel (DDC)

An I

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

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 is400 kb/s.

1.12 Clock generation

1.12.1 Oscillators

NEO-7 GNSS modules are available in Crystal and TCXO versions. The TCXO allows accelerated weak signal

acquisition, enabling faster start and reacquisition times.

1.12.2 Real-Time Clock (RTC)

The RTC is driven by a 32 kHz oscillator, which makes use of an external 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 later allow a hot or warm start.