LTE Module Series
EG21-G Hardware Design
EG21-G_Hardware_Design 29 / 100
USB_VBUS
USB_DP
USB_DM
AP_READY
VDD
USB_DP
USB_DM
GPIO
Module
Host
GND
GND
Figure 4: Sleep Mode Application with USB Remote Wakeup
Sending data to EG21-G through USB will wake up the module.
When EG21-G has a URC to report, the module will send remote wake-up signals via USB bus so as
to wake up the host.
3.5.1.3. USB Application with USB Suspension/Resume and RI Function
If the host supports USB suspension and resume, but does not support remote wake-up function, the RI
signal is needed to wake up the host.
There are three preconditions to let the module enter into the sleep mode.
Execute
AT+QSCLK=1
command to enable the sleep mode.
Ensure the DTR is held at high level or keep it open.
The host’s USB bus, which is connected with the module’s USB interface, enters into suspension
state.
The following figure shows the connection between the module and the host.
USB_VBUS
USB_DP
USB_DM
AP_READY
VDD
USB_DP
USB_DM
GPIO
Module
Host
GND
GND
RI
EINT