Usb Application With Usb Remote Wakeup Function - Quectel EC21 Series Hardware Design

The following figure shows the connection between the module and the host.

Driving the host DTR to low level will wake up the module.

When EC21 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 the host (can be configured to high level or low level
detection). Please refer to AT+QCFG="apready" command for details.
NOTE
AT+QCFG="apready" command is under development.

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 let the module enter into sleep mode.

Execute AT+QSCLK=1 command to enable 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's USB interface, enters into suspended
state.
EC21_Hardware_Design
Module
RXD
TXD
RI
DTR
AP_READY
GND
Figure 3: Sleep Mode Application via UART
TXD
RXD
EINT
GPIO
GPIO
GND
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LTE Module Series
EC21 Hardware Design
Host
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