LTE-A Module Series
EM12-G Hardware Design
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3.7. USB Interface
EM12-G provides one integrated Universal Serial Bus (USB) interface which complies with the USB
3.0/2.0 specifications and supports super speed (5Gbps) on USB 3.0, high speed (480 Mbps) and full
speed (12 Mbps) modes on USB 2.0. The USB interface is used for AT command communication, data
transmission, GNSS NMEA output, software debugging, firmware upgrade and voice over USB*.
The following table shows the pin definition of USB interface.
Table 9: Pin Definition of USB Interface
For more details about the USB 2.0 & 3.0 specifications, please visit http://www.usb.org/home.
The USB interface is recommended to be reserved for firmware upgrade in customers’ designs. The
following figure shows a reference circuit of USB 2.0 & USB 3.0 interface.
Pin No. Pin Name
I/O
Description
Comment
7
USB_DP
IO
USB 2.0 differential data bus (+)
Require differential impedance
of 90Ω
9
USB_DM
IO
USB 2.0 differential data bus (-)
29
USB3.0_TX-
DO
USB 3.0 transmit data (-)
Require differential impedance
of 90Ω
31
USB3.0_TX+
DO USB 3.0 transmit data (+)
35
USB3.0_RX-
DI
USB 3.0 receive data (-)
Require differential impedance
of 90Ω
37
USB3.0_RX+
DI
USB 3.0 receive data (+)