SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R26
System description
Page 63 of 217
1.9.3
USB interface
The USB interface is not available on SARA-G3 series modules.
1.9.3.1
USB features
SARA-U2 modules include a High-Speed USB 2.0 compliant interface with a maximum data rate of 480 Mbit/s
between the module and a host processor.
The module itself acts as a USB device and can be connected to any USB host such as a Personal Computer or an
embedded application microprocessor for AT commands, data communication, FW upgrade by means of the
FOAT feature, FW upgrade by means of the u-blox EasyFlash tool and for diagnostic purposes.
USB_D+
/
USB_D-
lines carry the USB serial bus data and signaling, while the
VUSB_DET
input senses the VBUS
USB supply presence (nom5 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
SARA-U2 series Data Sheet
[2]). 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.
SARA-U2 series modules can provide the following functions over the USB interface:
CDC-ACM for AT commands and data communication
CDC-ACM for GNSS tunneling
CDC-ACM for diagnostics
CDC-ACM for SAP (SIM Access Profile)
CDC-ECM for Ethernet-over-USB
CDC-ECM for Ethernet-over-USB function is not supported by the “00” product version.
The RI virtual signal is not supported over USB CDC-ACM by “04” product versions onwards.
Each USB profile of SARA-U2 module identifies itself by its VID (Vendor ID) and PID (Product ID) combination,
included in the USB device descriptor according to the
USB 2.0 specifications
If the USB interface of a SARA-U2 module is connected to the host before the module is switched on, or if the
module is reset with the USB interface connected to the host, then the VID and PID are automatically updated at
runtime, after the USB detection. Initially, VID and PID have the following values:
VID = 0x058B
PID = 0x0041
This VID and PID combination identifies a USB profile where no USB functions are available: AT commands must
not be sent to the module over the USB profile identified by this VID and PID combination.
Then, after a time period (roughly 5 s, depending on the host / device enumeration timings), the VID and PID are
by default updated to the following values, which are related to the SARA-U2 module default USB profile:
VID = 0x1546
PID = 0x1102
The following USB functions are available with the default USB profile, identified by PID = 0x1102:
7 USB CDC-ACM modem COM ports, enumerated as follows:
o
USB1, USB2, USB3: AT and data
o
USB4: GNSS tunneling
o
USB5: Primary Log (diagnostic purposes)
o
USB6: Secondary Log (diagnostic purposes)
o
USB7: SAP (SIM Access Profile)
