Usb Application With Usb Suspend/Resume And Ri Function; Usb Application Without Usb Suspend Function - Quectel EC200A Series Hardware Design

3.2.2.1. USB Application with USB Suspend/Resume and 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.
There are three preconditions to let the module enter sleep mode.
⚫
Execute AT+QSCLK=1 to enable the 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 Suspend state.
⚫
The following figure shows the connection between the module and the host.
⚫
Sending data to EC200A series through USB will wake up the module.
⚫
When EC200A series has a URC to report, the URC will trigger the behavior of MAIN_RI pin. Please
refer to Chapter 4.9 for details about MAIN_RI behavior.

3.2.2.2. USB Application without USB Suspend Function

If the host does not support USB Suspend function, please disconnect USB_VBUS with additional control
circuit to let the module enter into sleep mode.
⚫
Execute AT+QSCLK=1 command to enable the sleep mode.
⚫
Ensure the MAIN_DTR is held at high level or keep it open.
⚫
Disconnect USB_VBUS.
Module
USB_VBUS
USB_DP
USB_DM
AP_READY
MAIN_RI
GND
Figure 4: Sleep Mode Application with MAIN_RI
LTE Standard Module Series
Host
VDD
USB_DP
USB_DM
GPIO
EINT
GND