Service Guide

LTE Standard Module Series
EG91_Series_Hardware_Design
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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
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.
Figure 19: Reference Circuit of USB Interface
Pin Name Pin No. I/O Description Comment
USB_DP 9 AIO USB differential data (+)
USB 2.0 compliant
Require differential
impedance of 90 Ω.
USB_DM 10 AIO USB differential data (-)
USB_VBUS 8 AI USB connection detect Typical: 5.0 V
GND 3 Ground