Uart Application; Usb Application With Suspend Function - Quectel UC20 Manual

3.5.1.1. UART Application

If application processor communicates with module via UART interface, the following preconditions can
let the module enter into the sleep mode.
 Execute AT command AT+QSCLK=1 to enable the sleep mode.
 Drive DTR to high level.
The following figure shows the connection between the module and application processor.
Module
The RI of module is used to wake up the processor, and AP_READY will detect the sleep state of
processor (can be configured to high level or low level detection). You should pay attention to the level
match shown in dotted line between module and processor.
Drive DTR to low level will wake up the module.

3.5.1.2. USB Application with Suspend Function

If application processor communicates with module via USB interface, and processor supports USB
suspend function, the following preconditions can let the module enter into the sleep mode.
 Execute AT command AT+QSCLK=1 to enable the sleep mode.
 The processor's USB bus which is connected with the module USB interface enters into suspended
state.
The following figure shows the connection between the module and processor.
UC20_Hardware_Design
RXD
TXD
RI
DTR
AP_READY
GND
Figure 3: UART Sleep Application
Confidential / Released
UMTS/HSPA Module Series
UC20 Hardware Design
Processor
TXD
RXD
EINT
GPIO
GPIO
GND
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