LTE Standard Module Series
EC200U_Series_Hardware_Design 28 / 94
⚫
Driving MAIN_DTR to low level by the host can wake up the module.
⚫
When the module has a URC to report, the URC will trigger the behavior of MAIN_RI pin. Please
refer to
Chapter 3.22
for details about MAIN_RI behavior.
3.5.1.2. USB Application with USB Remote Wakeup Function
*
If the host supports USB suspend/resume and remote wakeup functions, the following three preconditions
must be met to make the module enter sleep mode.
⚫
Execute
AT+QSCLK=1
to enable sleep mode.
⚫
Ensure the MAIN_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 suspended 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
Figure 4: Sleep Mode Application with USB Remote Wakeup
⚫
Sending data to the module through USB can wake up the module.
⚫
When the module has a URC to report, the module will send remote wakeup signals via USB bus so
as to wake up the host.
1. USB suspend is supported on Linux system but not supported on Windows system.
2. Pay attention to the level match shown in dotted line between the module and the host.
3.5.1.3. USB Application with USB Suspend/Resume and MAIN_RI Function
*
If the host supports USB suspend/resume but does not support remote wakeup function, the MAIN_RI
signal is needed to wake up the host.
NOTE