LTE Module Series
EC21 Hardware Design
EC21_Hardware_Design Confidential / Released 29 / 94
The following figure shows the connection between the module and the host.
RXD
TXD
RI
DTR
AP_READY
TXD
RXD
EINT
GPIO
GPIO
Module
Host
GND
GND
Figure 3: Sleep Mode Application via UART
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.
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.
NOTE
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