UMTS/HSPA Module Series
UC20 Hardware Design
UC20_Hardware_Design Confidential / Released 33 / 82
VBAT
PWRKEY
Log off network about 1s to 60s
≥
0.6s
RUNNING
Power-down procedure
OFF
Module
Status
STATUS
(OD)
Figure 12: Timing of Turning off Module
During power-down procedure, module will send out U
RC “NORMAL POWER DOWN” via URC port first,
then log off network and save important data. After logging off, module sends out
“POWERED DOWN”
and shut down the internal power supply. The power on VBAT pins is not allowed to turn off before the
URC “POWERED DOWN” is output to avoid data loss. If logging off is not done within 60s, 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
and only the RTC is still active.
3.7.2.2. Turn off Module Using AT Command
It is also a safe way to use AT command
AT+QPOWD
to turn off the module, which is similar to turning off
the module via PWRKEY Pin.
Please refer to
document [1]
for details about the AT command of
AT+QPOWD
.
3.7.2.3. Automatic Shutdown
The module will constantly monitor the voltage applied on the VBAT, if the voltage
≤ 3.5V, the following
URC will be presented:
+QIND: “vbatt”,-1
If the voltage
≥ 4.21V, the following URC will be presented:
+QIND: “vbatt”,1
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