User's Manual

UMTS/HSPA Module Series
UG96 Hardware Design
UG96_Hardware_Design Confidential / Released 32 / 75
3.7.2. Turn off Module
The following procedures can be used to turn off the module:
 Normal power down procedure: Turn off the module using command AT+QPOWD.
 Emergency power down procedure: Turn off the module using the PWRDWN_N pin.
 Automatic shutdown: Turn off the module automatically if under-voltage or over-voltage is detected.
3.7.2.1. Turn off Module Using AT Command
There are several different ways to turn off the module. It is recommended to turn off the module from AT
command AT+QPOWD. It is a safe way to turn off the module. This command will let the module log off
from the network and allow the firmware to save important data before completely disconnecting the
power supply.
The power-down scenario is illustrated as the following figure.
VBAT
AT+QPOWD
Log off network about 2s to 40s
RUNNING
Power-down procedure
OFF
Module
Status
STATUS
RXD
Figure 12: Timing of Turning off through AT Command
During power-down procedure, module will log off from network and save important data. After logging off,
module sends out “OK”, and then sends out “POWERED DOWN” and shuts down the internal power
supply. The power on VBAT pins is not allowed to be turned off before the URC “POWERED DOWN” is
output to avoid data loss. If logging off is not done within 40s, module will shut down internal power supply
forcibly.
After that moment, the module enters the power down mode, no other AT commands can be executed,
only the RTC is still active. Please refer to document [1] for details about the AT command of
AT+QPOWD.