Users Manual

GSM/GPRS Module Series
M66 Hardware Design
M66_Hardware_Design Confidential / Released 29 / 82
3.4.2. Power Down
The following procedures can be used to turn off the module:
 Normal power down procedure: Turn off module using the PWRKEY pin
 Normal power down procedure: Turn off module using command AT+QPOWD
 Under-voltage automatic shutdown: Take effect when under-voltage is detected.
3.4.2.1. Power Down Module Using the PWRKEY Pin
It is a safe way to turn off the module by driving the PWRKEY to a low level voltage for a certain time. The
power down scenario is illustrated below.
Figure 9: Turn-off Timing
The power down procedure causes the module to log off from the network and allows the firmware to
save important data before completely disconnecting the power supply.
Before the completion of the power down procedure, the module sends out the result code shown below:
NORMAL POWER DOWN
After that moment, no further AT commands can be executed. Then the module enters the power down
mode, the RTC is still active.
NOTES