Usb Application Scenario; Usb Application With Usb Remote Wakeup Function; Usb Application With Usb Suspend/Resume And Main_Ri Function - Quectel RG520N-AT Hardware Design

⚫
When the module has a URC to report, MAIN_RI signal will wake up the host. See Chapter 4.14 for
details about RI behavior.

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, the following three preconditions
can make the module enter the sleep mode.
⚫
Execute AT+QSCLK=1 to enable sleep mode.
⚫
Ensure MAIN_DTR is held at 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.
Figure 5: Sleep Mode Application with USB Remote Wakeup
⚫
Sending data to the module through USB will wake up the module.
⚫
When the module has a URC to report, the module will send remote wake-up signals through 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 wakeup function, the MAIN_RI
signal is needed to wake up the host.
In this case, the following three preconditions can make the module enter the sleep mode.
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