User Manual

LARA-R2 series - System Integration Manual

UBX-16010573 - R02 Objective Specification System description

Page 46 of 148

1.9.2 USB interface

1.9.2.1 USB features

LARA-R2 series modules include a High-Speed USB 2.0 compliant interface with 480 Mb/s maximum data rate,

representing the main interface for transferring high speed data with a host application processor, supporting:

 AT command mode

 Data mode and Online command mode

 FW upgrades by means of the FOAT feature (see 1.14.13 and Firmware update application note [23])

 FW upgrades by means of the u-blox EasyFlash tool (see the Firmware update application note [23])

 Trace log capture (diagnostic purpose)

The module itself acts as a USB device and can be connected to a USB host such as a Personal Computer or an

embedded application microprocessor equipped with compatible drivers.

The USB_D+/USB_D- lines carry USB serial bus data and signaling according to the Universal Serial Bus Revision

2.0 specification [9], while the VUSB_DET input pin senses the VBUS USB supply presence (nominally 5 V at the

source) to detect the host connection and enable the interface.

The USB interface of the module is enabled only if a valid voltage is detected by the VUSB_DET input (see the

LARA-R2 series Data Sheet [1]). Neither the USB interface, nor the whole module is supplied by the VUSB_DET

input: the VUSB_DET senses the USB supply voltage and absorbs few microamperes.

The USB interface is controlled and operated with:

 AT commands according to 3GPP TS 27.007 [6], 3GPP TS 27.005 [7]

 u-blox AT commands (for the complete list and syntax see the u-blox AT Commands Manual [2])

The USB interface of LARA-R2 series modules, according to the configured USB profile, can provide different USB

functions with various capabilities and purposes, such as:

 CDC-ACM for AT commands and data communication

 CDC-ACM for GNSS tunneling

 CDC-ACM for SAP (SIM Access Profile)

 CDC-ACM for Diagnostic log

 CDC-NCM for Ethernet-over-USB

CDC-ACM for GNSS tunneling, CDC-ACM for SAP, and CDC-NCM for Ethernet-over-USB are not

supported by “02” product versions.

The USB profile of LARA-R2 series modules identifies itself by its VID (Vendor ID) and PID (Product ID)

combination, included in the USB device descriptor according to the USB 2.0 specification [9].

If the USB is connected to the host before the module is switched on, or if the module is reset (rebooted) with

the USB connected to the host, the VID and PID are automatically updated during the boot of the module. First,

VID and PID are the following:

 VID = 0x8087

 PID = 0x0716

This VID and PID combination identifies a USB profile where no USB function described above is available: AT

commands must not be sent to the module over the USB profile identified by this VID and PID combination.

See the u-blox AT Commands Manual [2] for the definition of the command mode, data mode, and online command mode.