EVB-USB3340 USB Transceiver Evaluation Board User Manual
Revision 1.1 (12-14-10)
4
SMSC USB3340 EVB
USER MANUAL
2.7
ULPI Signal Test Points
Probe points at location J2, provide access to all ULPI signals. Install the Tektronix logic analyzer probe
retention kit at J2 to probe these signals. Ordering information for the retention kit is provided in the
bill of materials.
2.8
Other Signal Test Points
There are five other test points located on the board for easy access. TP1 connects to the 5V supply
coming from the T&MT connector. TP2 connects to the 3.3V VDD supply coming from the T&MT
connector. TP3 connects to Ground. TP4 and TP5 connect to the Speaker Left and Speaker Right pins
respectively.
2.9
Speaker Left and Speaker Right signals
The Speaker Left and Speaker Right pins can accept audio signals ranging from 0V to 3.3V. If the
audio signal coming into the test points goes below 0V, biasing circuitry is required. Install R11, R14,
R15, and R16 with 10k resistors to add a DC bias to the audio signal. This will ensure the best signal
quality when routing through the USB3340.
2.10
Converting the EVB to an OTG System
“Out of the box”, the USB3340 EVB is delivered as a USB Device system. To convert it to be a USB
OTG development board, the following modifications must be made:
1. Install R13 (zero ohm resistor). This connects the VBUS 5V switch to the VBUS signal.
2. Remove R23. This is the R
VBUS
value required for a USB Device.
3. Install R10 (1.0K, 1W resistor). This is the R
VBUS
value required for a USB OTG Device.
Since the USB3340 is designed to accommodate up to 30V on VBUS, R10 is rated at 1W to
accommodate this entire voltage range. Refer to the USB3340 datasheet for more information on sizing
this resistor.
2.11
Converting the EVB to a Host System
“Out of the box”, the USB3340 EVB is delivered as a USB Device System. To convert it to be a USB
Host development board, the following modifications must be made:
1. Install R13 (zero ohm resistor). This connects the VBUS 5V switch to the VBUS signal.
2. Install C24 (120uF capacitor). This increases the value of C
VBUS
to be USB 2.0 Host compliant.
2.12
Converting the EVB to Support ULPI Clock Input Mode
“Out of the box”, the USB3340 EVB uses a crystal (Y1) as the clock reference, and is configured for
ULPI Clock Output Mode where CLKOUT sources a 60MHz clock. To convert the EVB to support ULPI
Clock Input Mode, the following changes must be made:
1. Install R12 (zero ohm resistor). This shorts CLKOUT to VDD18.
2. Install R3 (zero ohm resistor). This shorts REFCLK to the System Clock pin on the T&MT
connector.
3. Confirm that R4 is not populated.
4. Remove the following components to remove the crystal circuit: Y1, R17, C22, C23
Refer to the USB3340 datasheet for more information on ULPI Clock Input Mode.
