User's Manual

DE910 Series Hardware User Guide
1vv0301183 Rev.1 – 2015-2-13
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Reserved. Page 43 of 70
7. USB Port
The DE921 module includes a Universal Serial Bus (USB) transceiver, which operates at
USB high-speed (480Mbits/sec).
It is compliant with the USB 2.0 specification and can be used for diagnostic monitoring,
control and data transfers.
The table below describes the USB interface signals:
Pin Signal I/O Function Type
A19
USB_D+ I/O USB differential Data(+)
A17
USB_D- I/O USB differential Data(-)
A15
VBUS I Power sense for the internal USB transceiver 5V
The USB_DPLUS and USB_DMINUS signals have a clock rate of 480MHz. The signal
traces should be routed carefully. Trace lengths, number of vias and capacitive loading should
be minimized. The impedance value should be as close as possible to 90 Ohms differential.
WARNING:
Consider a mechanical design to protect DE921 or customer specific requirements from ESD
event to USB lines (A19, A17 and A15).