LISA-U2 series - System Integration Manual
UBX-13001118 - R19
Early Production Information
System description
Page 76 of 175
The USB drivers are available for the following operating system platforms:
Windows XP
Windows Vista
Windows 7
Windows 8
Windows 8.1
Windows CE 5.0
Windows Embedded CE 6.0
Windows Embedded Compact 7
Windows Embedded Automotive 7
Windows Mobile 5
Windows Mobile 6
Windows Mobile 6.1
Windows Mobile 6.5
LISA-U2 modules are compatible with standard Linux/Android USB kernel drivers.
1.9.3.2
USB and power saving
The modules automatically enter the USB suspended state when the device has observed no bus traffic for a
specific time period according to the
USB 2.0 specification
[7]. 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.
If the USB is suspended and a power saving configuration is enabled by the AT+UPSV command, the module
automatically enters the low power idle-mode whenever possible but it wakes up to active-mode according to
any required activity related to the network (e.g. the periodic paging reception described in section 1.5.3.3) or
any other required activity related to the functions / interfaces of the module.
The USB 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, for example due to incoming call,
URCs, data reception on a socket. The remote wake-up signaling 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
USB 2.0 specifications
For the module current consumption description with power saving enabled and USB suspended, or with power
saving disabled and USB not suspended, see the sections 1.5.3.3 and 1.5.3.4 and
LISA-U2 series Data Sheet
1.9.3.3
USB application circuit
Since the module acts as a USB device, the USB supply (5.0 V typ.) must be provided to
VUSB_DET
by the
connected USB host. The USB interface is enabled only when a valid voltage as USB supply is detected by the
VUSB_DET
input. 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_D+
and
USB_D-
lines carry the USB serial data and signaling. The lines are used in single ended mode
for relatively low speed signaling handshake, as well as in differential mode for fast signaling and data transfer.
USB pull-up or pull-down resistors on pins
USB_D+
and
USB_D-
as required by the
Universal Serial Bus Revision
2.0 specification
[7] are part of the USB pad driver and do not need to be externally provided.