GSM/GPRS Module Series
M66 Hardware Design
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VBAT
PWRKEY
(INPUT)
VDD_EXT
(OUTPUT)
Logout net about 2s to 12s
0.7s<Pulldown<1s
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.
1. This unsolicited result codes do not appear when autobauding is active and DTE and DCE are not
correctly synchronized after start-up. The module is recommended to set to a fixed baud rate.
2.
As logout network 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.
3.4.2.2. Power Down Module Using AT Command
It is also a safe way to turn off the module via AT command
AT+QPOWD=1
. This command will let the
module log off from the network and allow 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. And then the module enters the power
down mode, only the RTC is still active.
NOTE
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