Usb Interface - Quectel EM12-G Hardware Design

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
Pin No. Pin Name
7 USB_DP
9 USB_DM
29 USB3.0_TX-
31 USB3.0_TX+
35 USB3.0_RX-
37 USB3.0_RX+
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.
EM12-G_Hardware_Design
I/O Description
IO USB 2.0 differential data bus (+)
IO USB 2.0 differential data bus (-)
DO USB 3.0 transmit data (-)
DO USB 3.0 transmit data (+)
DI USB 3.0 receive data (-)
DI USB 3.0 receive data (+)
LTE-A Module Series
EM12-G Hardware Design
Comment
Require differential impedance
of 90Ω
Require differential impedance
of 90Ω
Require differential impedance
of 90Ω
32 / 62