SMARC T335x Carrier Board Hardware Design Guide, Document Revision 1.2
2.3 USB Interface
The Universal Serial Bus interface of the
SMARC
module is compliant to USB
2.0 and backward compatible to USB 1.1 specification.
SMARC
specifies a
minimum configuration of 1 USB client port that can be configured as host port
or
OTG
port, and a minimum configuration of 1 USB host port up to a
maximum of 2 ports. USB Port0 can be optionally configured to be used as a
USB host port or
OTG
port.
SMARC T335X
has one USB 2.0 client port (
USB0
) that can be configured as
a host port or OTG port, and one USB 2.0 host port (
USB1
). Port
USB2
is
unused.
2.3.1. USB Signal
The following table shows the USB signals of
USB0
.
SMARC Edge Finger
I/O
Type
Power
Rail
Description
Pin#
Pin
Name
P60
USB0+
IO
USB
3.3V
Positive differential USB signal,
OTG capable
P61
USB0
‐
IO
USB
3.3V
Negative differential USB signal,
OTG capable
P62
USB0_EN_OC#
IO
OD
3.3V
Enable signal for the bus voltage
output in host mode and Over
current input signal for the USB0
interface
Pulled low by Module OD driver to
disable USB0 power
Pulled low by Carrier OD driver to
indicate over-current situation
If this signal is used, a pull-up is
required on the Carrier
P63
USB0_VBUS_DET
I
CMOS
3.3V/ 5V
tolerant
Bus voltage detection in the OTG
client mode
P64
USB0_OTG_ID
I
CMOS
3.3V
Cable identification pin for the
OTG