Service Guide
Table Of Contents
- Safety Information
- About the Document
- Contents
- Table Index
- Figure Index
- 1 Introduction
- 2 Product Overview
- 3 Operating Characteristics
- 4 Application Interfaces
- 5 Antenna Interfaces
- 6 Reliability, Radio, and Electrical Characteristics
- 7 Mechanical Information
- 8 Storage, Manufacturing, and Packaging
- 9 Appendix References
LTE Standard Module Series
EG915U_Series_Hardware_Design 29 / 90
3.2.2. USB Application Scenario
3.2.2.1. USB Application with USB Remote Wakeup Function
If the host supports USB suspend/resume and remote wakeup function, three preconditions must be met
to make the module enter the sleep mode:
⚫ Execute AT+QSCLK=1 command to enable the sleep mode.
⚫ Ensure the MAIN_DTR is held at a high level or keep it open.
⚫ Ensure the host’s USB bus, which is connected with the module’s USB interface, enters suspend
state.
The following figure illustrates the connection between the module and the host.
USB_VBUS
USB_DP
USB_DM
AP_READY
VDD
USB_DP
USB_DM
GPIO
Module
MCU
GND
GND
Figure 4: Sleep Mode Application with USB Remote Wakeup
⚫ You can wake up the module by sending data to it through USB.
⚫ When the module has a URC to report, the module will send remote wake-up signals to USB bus to
wake up the host.
⚫
3.2.2.2. USB Application with USB Suspend/Resume and MAIN_RI Function
If the host supports USB suspend/resume, but does not support remote wake-up function, the MAIN_RI
signal is needed to wake up the host.
USB suspend is supported on Linux system but not on Windows system.
NOTE