Digilent EVB-USB3300-XLX - Manual (Page 2)

EVB-USB3300-XLX User Manual
Revision 0.4 (06-29-07) SMSC EVB-USB3300-XLX
2
1 Introduction
The SMSC USB3300 USB Transceiver features a ULPI interface to support systems implementing a
USB Host, Device, or On-the-Go (OTG) system. SMSC supplies a complete family of PHY products
to meet the needs of many applications.
2 Overview
The EVB-USB3300-XLX is a Daughter Card designed to plug into a user's Xilinx ML401 development
system using a header connector. The card attaches to a USB link layer to create a USB Host, Device,
or On-the-Go (OTG) system. The digital interface meets the UTMI+ Low Pin Interface (ULPI)
specification. The ULPI specification can be downloaded from the SMSC web site at
http://www.smsc.com/main/catalog/usb3300.html. The EVB-USB3300-XLX includes the USB300 and
all associated external components.
Figure 3 shows a schematic of the EVB.
2.1 3.3 Volt Power Supply
The EVB-USB3300-XLX requires a 3.3 volt supply capable of providing 80mA of current to be present
at the J2 header pins 16, 19, 22 and 25. For device only applications this is the only power the EVB-
USB3300-XLX requires.
2.2 Crystal Oscillator
A 24 MHz crystal is connected to the internal oscillator of the USB3300. A PLL circuit in the USB3300
generates the 60MHz CLKOUT signal used by the link layer.
2.3 USB Connector
A standard Mini-AB connector is provided to attach a USB cable.
2.4 Supplying VBUS Power
In host or OTG applications the EVB-USB3300-XLX must provide 5 volts on V
BUS
. The EVB-USB3300-
XLX includes a 5 volt switch that can connect 5 volts to V
BUS
. The EVB-USB3300-XLX 5 volt supply
can come from either external power supplied at J5 or from header J1 pins 1, 4, 7 and 10. Jumper J6
must be installed to source +5V for the ML501 header. When using J5 to supply external power, J6
must be removed.
The 5 volt switch is controlled by the CPEN signal from the USB3300. The CPEN state is controlled
by ULPI registers in the USB3300 per the ULPI specification. The 5 volt switch has an undervoltage
lockout that turns the switch off if the VBUS voltage is low and the switch prevents reverse current
flow (backdrive) when in the off state. The switch does not provide protection from reverse currents
when in the on state. The user should take care to ensure the switch is off when V
BUS
is being sourced
by the USB cable.
In host mode, connector J7 should be installed to add capacitance to V
BUS
. The USB2.0 specification
requires this extra capacitance be present in host implementations.