Specifications

XT65/XT75 Hardware Interface Description
3.11 USB Interface
s
XT65_XT75_HD_v01.001 Page 55 of 133 2007-1-8
Confidential / Released
3.11 USB Interface
XT65/XT75 supports a USB 2.0 Full Speed (12Mbit/s) device interface. It can be operated on a USB 2.0 Full
Speed or High Speed root hub (a PC host), but not on a generic USB 2.0 High Speed hub which translates High
Speed (480 Mbit/s/) to Full Speed (12 Mbit/s).
The USB port has different functions depending on whether or not Java is running. Under Java, the lines may be
used for debugging purposes (see [18] for further detail). If Java is not used, the USB interface is available as a
command and data interface and for downloading firmware.
The USB I/O-pins are capable of driving the signal at min 3.0V. They are 5V I/O compliant.
To properly connect the module’s USB interface to the host a USB 2.0 compatible connector is required. Fur-
thermore, the USB modem driver delivered with XT65/XT75 must be installed as described below.
The USB host is responsible for supplying, across the VUSB_IN line, power to the module’s USB interface, but
not to other XT65/XT75 interfaces. This is because XT65/XT75 is designed as a self-powered device compliant
with the “Universal Serial Bus Specification Revision 2.0”
2
.
To properly connect the module's USB interface to the host a USB 2.0 compatible connector is required. For
more information on how to install a USB modem driver and on how to integrate USB into XT65/XT75 applica-
tions see [11].
2.
The specification is ready for download on http://www.usb.org/developers/docs/
Figure 17: USB circuit