ROMSPG3.01 datasheet(13/31 Pages) U-BLOX

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CAM-M8 - Data Sheet

UBX-15031574 - R04

Page 13 of 31

Production Information

1.15 Protocols and interfaces

Protocol

Type

NMEA

Input/output, ASCII, 0183, version 4.0 (Configurable to V 2.1, V 2.3 or V4.1 )

UBX

Input/output, binary, u-blox proprietary

RTCM

Input, message 1, 2, 3, 9

Table 4: Available Protocols

All protocols are available on UART, DDC (I2C compliant) and SPI. For specification of the various

protocols, see the u-blox 8 / u-blox M8 Receiver Description Including Protocol Specification [2].

1.16 Interfaces

A number of interfaces are provided for data communication. The embedded firmware uses these

interfaces according to their respective protocol specifications.

1.16.1 UART

The CAM-M8 series modules support 1 UART interfaces, 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.

1.16.2 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.

☞ 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 20) to ground (see

section 3.1).

1.16.3 Display Data Channel (DDC)

An I2C 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 the Fast-Mode of the I2C industry standard. Since the maximum

SCL clock frequency is 400 kHz, the maximum transfer rate is 400 kb/s.

☞ The maximum bit rate is 400 kb/s. The interface stretches the clock when slowed down while

serving interrupts, so real bit rates may be slightly lower.

ROMSPG3.01 Datasheet(PDF) 13 Page - u-blox AG