Product Info

LTE Standard Module Series
EC25 Series Hardware Design
EC25_Series_Hardware_Design 41 / 134
⚫ Sending data to EC25 via USB will wake up the module.
⚫ When EC25 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 Suspend/Resume and RI Function
If the host supports USB suspend 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 sleep mode.
⚫ Execute AT+QSCLK=1 command to enable 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 suspend 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
Figure 5: Sleep Mode Application with RI
⚫ Sending data to EC25 via USB will wake up the module.
⚫ When EC25 has a URC to report, RI signal will wake up the host.
3.5.1.4. USB Application without USB Suspend Function
If the host does not support USB suspend function, USB_VBUS should be disconnected via an additional
control circuit to let the module enter sleep mode.
⚫ Execute AT+QSCLK=1 command to enable sleep mode.
⚫ Ensure the DTR is held at high level or keep it open.
⚫ Disconnect USB_VBUS.
The following figure shows the connection between the module and the host.