HE920 Hardware User Guide
1vv0301014 Rev.9 – 2014-01-23
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
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Page 51 of 84
8.
USB Port
The HE920 module includes a Universal Serial Bus (USB) transceiver, which operates at
USB low-speed (1.5Mbits/sec), USB full-speed (12Mbits/sec) and 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 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.
The table below describes the USB interface signals:
TIP:
HE920 does NOT support host device operation at the moment, that is, it works as a slave
device. Consequently USB_ID must be opened (not connected).
Pad No.
Signal
I/O
Function
Type
NOTE
A18
USB_VBUS
AI
Power sense for the internal USB
transceiver.
5V
F19
USB_D-
I/O
USB differential Data (-)
D19
USB D+
I/O
USB differential Data (+)
B19
USB_ID
(for future use)
