u-blox LARA-R2 series System Integration Manual Download

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LARA-R2 series - System Integration Manual

UBX-16010573 - R02

Objective Specification

System description

Page 51 of 148



The RTC synchronization signal to the GNSS receiver: “GNSS RTC sharing” function provided by

GPIO4

improves GNSS receiver performance, decreasing the Time To First Fix (TTFF), and thus allowing to calculate
the position in a shorter time with higher accuracy. When GPS local aiding is enabled, the cellular module
automatically uploads data such as position, time, ephemeris, almanac, health and ionospheric parameter
from the positioning receiver into its local memory, and restores this to the GNSS receiver at the next power
up of the positioning receiver

For more details regarding the handling of the DDC (I

C) interface, the GNSS aiding features and the

GNSS related functions over GPIOs, see section 1.12, to the

u-blox AT Commands Manual

[2] (AT+UGPS,

AT+UGPRF, AT+UGPIOC AT commands) and the

GNSS Implementation Application Note

[22].

“GNSS Tx data ready” and “GNSS RTC sharing” functions are not supported by all u-blox GNSS receivers
HW or ROM/FW versions. See the

GNSS Implementation Application Note

[22] or to the

Hardware

Integration Manual

of the u-blox GNSS receivers for the supported features.

As additional improvement for the GNSS receiver performance, the

V_BCKP

supply output of the cellular

modules can be connected to the

V_BCKP

supply input pin of u-blox positioning chips and modules to provide

the supply for the GNSS real time clock and backup RAM when the

VCC

supply of the cellular module is within

its operating range and the

VCC

supply of the GNSS receiver is disabled.

This enables the u-blox positioning receiver to recover from a power breakdown with either a hot start or a
warm start (depending on the duration of the GNSS receiver

VCC

outage) and to maintain the configuration

settings saved in the backup RAM.

1.9.5

SDIO interface

Secure Digital Input Output interface is not supported by LARA-R2 series modules “02” product versions.

LARA-R2 series modules include a 4-bit Secure Digital Input Output interface (

SDIO_D0

SDIO_D1

SDIO_D2

SDIO_D3

SDIO_CLK

SDIO_CMD

) designed to communicate with an external u-blox short range Wi-Fi module:

the cellular module acts as an SDIO host controller which can communicate over the SDIO bus with a compatible
u-blox short range radio communication Wi-Fi module acting as SDIO device.
The SDIO interface is the only one interface of  LARA-R2 series modules dedicated for communication between
the u-blox cellular module and the u-blox short range Wi-Fi module.
The AT commands interface is not available on the SDIO interface of LARA-R2 series modules.

Combining a u-blox cellular module with a u-blox short range communication module gives designers full access
to the Wi-Fi module directly via the cellular module, so that a second interface connected to the Wi-Fi module is
not  necessary.  AT  commands  via  the  AT  interfaces  of  the  cellular  module  allows  a  full  control  of  the  Wi-Fi
module  from  any  host  processor,  because  Wi-Fi  control  messages  are  relayed  to  the  Wi-Fi  module  via  the
dedicated SDIO interface.
u-blox has implemented special features in the cellular modules to ease the design effort for the integration of a
u-blox cellular module with a u-blox short range Wi-Fi module to provide Router functionality.
Additional custom function over GPIO pins is designed to improve the integration with u-blox Wi-Fi modules:



Wi-Fi enable

Switch-on / switch-off the Wi-Fi

Wi-Fi enable function over GPIO is not supported by LARA-R2 series modules “02” product versions.