Usb Interface - Quectel EG91 Series Hardware Design

3.10. USB Interface

EG91 series module contains one integrated Universal Serial Bus (USB) interface which complies with
the USB 2.0 specification and supports high-speed (480 Mbps) and full-speed (12 Mbps) modes.
The USB interface acts as slave only, and is used for AT command communication, data transmission,
GNSS NMEA sentences output, software debugging, firmware upgrade and voice over USB.
The following table shows the pin definition of USB interface.
Table 10: Pin Definition of USB Interface
Pin Name Pin No.
USB_DP 9
USB_DM 10
USB_VBUS 8
GND 3
For more details about USB 2.0 specifications, visit http://www.usb.org/home.
The USB interface is recommended to be reserved for firmware upgrade in your design. The following
figure shows a reference circuit of USB interface.
EG91_Series_Hardware_Design
I/O Description
AIO USB differential data (+)
AIO USB differential data (-)
AI USB connection detect
Ground
Figure 19: Reference Circuit of USB Interface
LTE Standard Module Series
Comment
USB 2.0 compliant
Require differential
impedance of 90 Ω.
Typical: 5.0 V
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