SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R08
Objective Specification
System description
Page 55 of 188
If the USB interface of a SARA-U2 module is connected to the host before the module switch on, or if the
module is reset with the USB interface connected to the host, the VID and PID are automatically updated
runtime, after the USB detection. First, VID and PID are the following:
VID = 0x058B
PID = 0x0041
This VID and PID combination identifies a USB profile where the set of USB functions described in details above
(AT and Data, GNSS tunneling, Diagnostic, SAP) are not 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
updated to the following ones, which are related to the SARA-U2 module USB profile with the set of USB
functions described in details above (AT and Data, GNSS tunneling, Diagnostic, SAP):
VID = 0x1546
PID = 0x1102
1.9.3.2
USB and power saving
If power saving is enabled by the AT+UPSV command, the modules automatically enter the USB suspended state
when the device has observed no bus traffic for a specified time period (see the
[14]). In
suspended state, the module maintains any USB internal status as device. In addition, the module enters the
suspended state when the hub port it is attached to is disabled. This is referred to as USB selective suspend.
The module exits suspend mode when there is bus activity. If the USB is connected and not suspended, the
module is forced to stay in active-mode, therefore the AT+UPSV settings are overruled but they have effect on
the power saving configuration of the other interfaces.
The modules are capable of USB remote wake-up signaling: i.e. it may request the host to exit suspend mode or
selective suspend by using electrical signaling to indicate remote wake-up. This notifies the host that it should
resume from its suspended mode, if necessary, and service the external event. Remote wake-up is accomplished
using electrical signaling described in the
For the module current consumption description with power saving enabled and USB suspended, or with power
saving disabled and USB not suspended, see sections 1.5.1.4, 1.5.1.5 and
SARA-U2 series Data Sheet
1.9.4
DDC (I
2
C) interface
SARA-G300 and SARA-G310 modules do not support DDC (I
2
C) interface.
An I
2
C bus compatible Display Data Channel (DDC) interface for communication with u-blox GNSS receivers is
available on
SDA
and
SCL
pins of SARA-G340, SARA-G350 and SARA-U2 modules. Only this interface provides
the communication between the u-blox cellular module and u-blox positioning chips and modules.
SARA-U2 modules additionally support the communication with other external I
2
C devices as an audio codec.
The AT commands interface is not available on the DDC (I
2
C) interface.
DDC (I
2
C) slave-mode operation is not supported: the cellular module can act as master only, and the connected
u-blox GNSS receiver or any other external I
2
C devices acts as slave in the DDC (I
2
C) communication.
Two lines, serial data (
SDA
) and serial clock (
SCL
), carry information on the bus.
SCL
is used to synchronize data
transfers, and
SDA
is the data line. To be compliant to the I
2
C bus specifications, the module interface pins are
open drain output and pull up resistors must be externally provided conforming to the
I
2
C bus specifications
u-blox has implemented special features in SARA-G340, SARA-G350 and SARA-U2 modules to ease the design
effort required for the integration of a u-blox cellular module with a u blox GNSS receiver.
