User's Manual

LTE Module
EC20 Hardware Design
EC20_Hardware_Design Confidential / Released 24 / 83
 Driving host DTR to low level will wake up the module.
 When EC20 has URC to report, RI signal will wake up the host. Refer to Chapter 3.16 for details
about RI behavior.
 AP_READY will detect the sleep state of host (can be configured to high level or low level detection).
Refer to AT command AT+QCFG=“apready” for details.
3.5.1.2. USB Application with USB Remote Wakeup Function
If host supports USB suspend/resume and remote wakeup function, the following part will show the sleep
application.
There are three preconditions to let the module enter into the sleep mode.
 Execute AT command AT+QSCLK=1 to enable the sleep mode.
 Ensure the DTR is held in high level or keep it open.
 The host’s USB bus which is connected with the module USB interface enters into suspended state.
The following figure shows the connection between the module and host.
USB_VBUS
USB_DP
USB_DM
AP_READY
VDD
USB_DP
USB_DM
GPIO
Module
Host
GND
GND
Figure 4: Sleep Application with USB Remote Wakeup
 Sending data to EC20 through USB will wake up the module.
 When EC20 has URC to report, module will send remote wake-up signals on USB BUS to wake up
the host.