SIM802 Hardware Design
over-voltage is detected
z
Over-temperature or under-temperature automatic shutdown: Take effect if over-temperature
or under-temperature is detected
3.4.2.1 Turn off SIM802 using the PWRKEY Pin (Power down)
You can turn off the SIM802 by driving the PWRKEY to a low level voltage for a period time.
The power down scenarios illustrate as figure 9.
This procedure lets the module log off from the network and allows the software to enter into a
secure state and saves data before completely disconnecting the power supply.
Before the completion of the switching off procedure the module will send out result code:
POWER DOWN
After this moment, the AT commands can not be executed. Module enters the POWER DOWN
mode, only the RTC is still active. POWER DOWN can also be indicated by STATUS Pin, which
is a low level voltage in this mode.
STATUS
（
OUTPUT
）
V
IL
<0.2*VBAT
V
IH
>0.6*VBAT
1000ms > Pulldown > 500ms
Hiz
Logout net about 2000ms to 8000ms
PWRKEY
（
INPUT
）
Figure 9: Timing of turn off system
3.4.2.2 Turn off SIM802 using AT command
You can use an AT command “AT+CPOWD=1” to turn off the module. This command will make
the module log off from the network and allow the software to enter into a secure state and save
data before completely disconnecting the power supply.
Before the completion of the switching off procedure the module will send out result code:
NORMAL POWER DOWN
After this moment, any AT commands can not be executed. Module enters into the POWER
DOWN mode, only the RTC is still active. POWER DOWN can also be indicated by STATUS
Pin, which is a low level voltage in this mode.
SIM802_HD_V2.01
12.01.2010
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