Error! No text of specified style in document. - System Integration Manual
CDMA-2X-11004-P1
Objective Specification
System description
Page 44 of 79
40.4.3
USB interface
Error! No text of specified style in document. modules provide a full-speed USB interface at 12 Mb/s
compliant with the Universal Serial Bus Revision 2.0 specification [9]. 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 Error!
No text of specified style in document. modules emulate all serial control logical lines.
If the logical DTR line isn't enabled by the USB host, the module doesn’t answer to AT
commands by the USB interface.
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 impedance.
Pull-up or pull-down resistors and external series resistors
as required by the USB 2.0 high-speed specification [9]
are part of the USB pad driver and need not be
provided externally.
USB_D-
USB Data Line D-
90
Ω
nominal differential impedance.
Pull-up or pull-down resistors and external series resistors
as required by the USB 2.0 high-speed specification [9]
are part of the USB pad driver and need not be
provided externally.
Table 12: USB pins
The USB interface pins ESD sensitivity rating is 1 kV (Human Body Model according to JESD22-
A114F). Higher protection level could be required if the lines are externally accessible on the
application board. Higher protection level 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.
Error! No text of specified style in document. module identifies itself by its VID (Vendor ID) and PID
(Product ID) combination, included in the USB device descriptor. VID and PID of Error! No text of
specified style in document. modules are the following:
VID = 0x1546 PID = 0x1121
40.4.3.1
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 [9] are part of the USB pad driver and do not need to be externally
provided.
External series resistors on pins USB_D+ and USB_D- as required by the Universal Serial Bus Revision 2.0
specification [9] are also integrated: characteristic impedance of USB_D+ and USB_D- lines is
specified by the USB standard. The most important parameter is the differential characteristic
impedance applicable for odd-mode electromagnetic field, which should be as close as possible
