User's Manual

GSM/GPRS/GNSS Module Series

MC20 Hardware Design

MC20_Hardware_Design Confidential / Released 40 / 95

3.5.2. 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.

3.5.2.1. 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 in the following figure.

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

1. When unsolicited result codes do not appear when autobauding is active and DTE & DCE are not

correctly synchronized after start-up, the module is recommended to be set to a fixed baud rate.

2. As network logout time is related to the local mobile network, it is recommended to delay about 12

seconds before disconnecting the power supply or restarting the module.

After that moment, no further AT commands can be executed. Then the module enters the power down

mode.

Make sure that VBAT is stable before pulling down PWRKEY pin. The time of T

is recommended to be

100ms.

NOTE

NOTES