UMTS/HSPA Module Series
UC20 Hardware Design
UC20_Hardware_Design Confidential / Released 26 / 82
match shown in dotted line between module and processor.
Driving 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.
USB_VBUS
USB_DP
USB_DM
AP_READY
VDD
USB_DP
USB_DM
GPIO
Module
Processor
GND
GND
RI
EINT
Figure 4: USB Application with Suspend Function
When the processor’s USB bus returns to resume state, the module will be woken up.
3.5.1.3. USB Application without Suspend Function
If application processor communicates with module via USB interface, and processor does not support
USB suspend function, you should disconnect USB_VBUS with additional control circuit to let the module
enter into sleep mode.
Execute AT command
AT+QSCLK=1
to enable the sleep mode.
Disconnect USB_VBUS.
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