User's Manual

Smart Machine Smart Decision
SIM868_Hardware_Design_V1.00 22 2016-06-20
Note: Hardware power off voltage is 3.0V.
4.1.2. Monitoring Power Supply
AT command “AT+CBC” can be used to monitor the VBAT voltage. For detail, please refer to document [1].
4.2. Power on/off SIM868
4.2.1. Power on SIM868
Customer can power on SIM868 by pulling down the PWRKEY pin for at least 1 second and release. This pin is
already pulled up to 3V in the module internal, so external pull up is not necessary. Reference circuits are shown
as below.
4.7K
47K
Turn on/off
impulse
PWRKEY
Power
on/off logic
100K
3V
Module
1K
Figure 10: Powered on/down module using transistor
PWRKEY
Power
on/off logic
100K
3V
Module
1K
Figure 11: Powered on/down module using button
The power on timing is illustrated as in the following figure.
Figure 12: Timing of power on module