User's Manual

PW2050 Embedded Device Server Integration Guide 22
USB Host Port
The PW2050 Module has two USB 2.0 Host port interfaces for connection to downstream USB
devices. Each port consists of a differential pair. Port USB2 is a high speed port and port
USB3 is a full speed port. These signals should be routed as 90 ohm differential pairs on a
signal layer next to the signal ground plane. The use of vias should be minimized on these
signals. The USB signals can be connected to a USB Type A dual USB port as shown in the
figure below or directly to an IC with a USB device port. If connecting to an external port that is
user accessible it is recommended to add a TVS diode array to the signal nets for ESD
protection. The ESD array shown in the figure is of type NXP, IP4234CZ6. If connecting to an
off board device that needs power add a USB power switch to current limit the 5V power
connection at the connector. USB requires that each port be limited to 500 mA maximum
sustained current. If using the USB host ports the end system must take into account the
amount of power consumed by the PW2050 module and each USB device connected to the
host ports. The schematic below shows how to connect 5V to a USB host connector using an
ST, STMPS2151 Power Distribution Switch. The USB host port 5V power is not provided by
the PW2050 module. If the USB host ports are unused their pins may be left unconnected.
Table 2-10 USB Host Port Signals
Pin Name Description PW2050 Pins Signal
Requirement
Type A USB
Host connector
pin
USB2+/HHSDPB USB HS Host Port
A Positive pin
21 Route as 90 ohm
differential pair
B3
USB2-/HHSDPM USB HS Host Port
A Negative pin
22 Route as 90 ohm
differential pair
B2
USB3+/HFSDPC USB FS Host Port
B Positive pin
52 Route as 90 ohm
differential pair
A3
USB3-/HFSDMC USB FS Host Port
B Negative pin
53 Route as 90 ohm
differential pair
A2
5V(User
supplied)
5V power for USB
connector
Current limit to
500 mA per port
A1, B1
Ground Signal Ground Ground Ground plane A4, B4
LEDs
The PW2050 embedded device server contains several external signals that are intended to
drive external status LEDs. The LEDs are listed below. The signals may be connected as
shown in the reference schematic figure below.
Note: The System LED usually remains on. When the Default button is pressed for 5-6
seconds, the System LED starts blinking every second to indicate the default button can
be released to complete resetting the unit to factory default. The unit reboots after