Integration Manual

LISA-U2 series - System Integration Manual
UBX-13001118 - R25 System description Page 74 of 182
1.9.3 USB interface
LISA-U2 modules provide a high-speed USB interface at 480 Mbit/s compliant with the Universal
Serial Bus Revision 2.0 specification [7]. It acts as a USB device and can be connected to any USB host
such as a PC or other application processor.
The USB-device shall look for all upper SW layers like any other serial device. This means that the
LISA-U2 modules emulate all serial control logical lines.
Name
Description
Remarks
VUSB_DET
USB detect input
Apply 5 V typical to enable USB
USB_D+
USB Data Line D+
90 Ω nominal differential characteristic impedance (Z
0
)
30 Ω nominal common mode characteristic impedance (Z
CM
)
Pull-up or pull-down resistors and external series resistors as
required by the USB 2.0 high-speed specification [7] are part of
the USB pad driver and need not be provided externally.
USB_D-
USB Data Line D-
90 Ω nominal differential characteristic impedance (Z
0
)
30 Ω nominal common mode characteristic impedance (Z
CM
)
Pull-up or pull-down resistors and external series resistors as
required by the USB 2.0 high-speed specification [7] are part of
the USB pad driver and need not be provided externally.
Table 33: USB pins
☞ The USB interface pins ESD sensitivity rating is 1 kV (Human Body Model according to
JESD22-A114F). Higher protection levels could be required if the lines are externally accessible on
the application board. Higher protection levels can be achieved by mounting a very low capacitance
(i.e. less or equal to 1 pF) ESD protection (e.g. Tyco Electronics PESD0402-140 ESD protection
device) on the lines connected to these pins, close to the accessible points.
1.9.3.1 USB features
LISA-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.
The USB_D+/USB_D- lines carry the USB serial bus data and signaling, 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 LISA–U2 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 only a few
microamperes.
LISA-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 diagnostic
 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 "01", "x2", "63" and "68" versions.