Smart Machine Smart Decision
4.2.2.
Power down SIM2000S
SIM2000S will be powered down in the following situations:
z
Normal power down procedure: power down SIM2000S by the PWRKEY pin.
z
Normal power down procedure: power down SIM2000S by AT command “AT+CPOWD=1”.
z
Abnormal power down: over-voltage or under-voltage automatic power down.
z
Abnormal power down: over-temperature or under-temperature automatic power down.
4.2.2.1.
Power down SIM2000S by the PWRKEY Pin
User can power down SIM2000S by pulling down the PWRKEY pin for at least 1 second and release. Please
refer to the power on circuit. The power down timing is illustrated in the following figure.
SIM2000S_Hardware_Design_V1.00
21
2014-02-27
STATUS
(Output)
Figure 11: Timing of power down SIM2000S by PWRKEY
This procedure makes the module log off from the network and allows the software to enter into a secure state to
save data before completely shut down.
Before the completion of the power down procedure, the module will send URC:
NORMAL POWER DOWN
At this moment, AT commands can not be executed any more. The status light will be powered off at this time.
4.2.2.2.
Power down SIM2000S by AT Command
SIM2000S can be powered down by AT command “AT+CPOWD=1”. This procedure makes the module log off
from the network and allows the software to enter into a secure state to save data before completely shut down.
Before the completion of the power down procedure, the module will send URC:
NORMAL POWER DOWN
At this moment, AT commands can not be executed any more. The status light will be powered off at this time.
For detail about AT command “AT+CPOWD”, please refer to document [1].
4.2.2.3.
Over-voltage or Under-voltage Power down
The module software monitors the VBAT voltage constantly.
If the voltage
≤
3.5V, the following URC will be reported:
UNDER-VOLTAGE WARNNING
V
IL
< 0.4V
V
IH
> 1.5V
5S > Pulldown >1S
PWRKEY
(Input)
Delay > 1.7S
Logoff net
V
OH
< 0.1V
Serial Port
Undefined
Active